{"id":2722,"date":"2026-10-13T17:19:37","date_gmt":"2026-10-13T09:19:37","guid":{"rendered":"https:\/\/www.britecelectric.com\/?post_type=blog&#038;p=2722"},"modified":"2026-10-14T17:20:09","modified_gmt":"2026-10-14T09:20:09","slug":"how-high-temperatures-derate-10ka-spds","status":"publish","type":"blog","link":"https:\/\/www.britecelectric.com\/el\/blog\/how-high-temperatures-derate-10ka-spds\/","title":{"rendered":"How High Operating Temperatures Derate the Performance of 10kA SPDs"},"content":{"rendered":"<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Reviewed by the Britec Electric engineering team. Britec Electric, based in Wenzhou, Zhejiang, China, has manufactured surge protective devices (SPDs) since 2003. Our products are tested and certified to IEC\/EN 61643-11 by TUV, CE and Intertek SEMKO. Drawing on that field experience, this guide explains why a 10kA SPD loses part of its rated performance as its operating temperature climbs \u2014 and what specifiers and installers should do about it.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">What 10kA Actually Means on an SPD<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">When a manufacturer labels a device a 10kA SPD, the number refers to its nominal discharge current, written In, measured with the 8\/20 \u00b5s current waveform defined in IEC\/EN 61643-11. In is the surge current the SPD can absorb repeatedly \u2014 typically a sequence of standardized 8\/20 \u00b5s strikes \u2014 without failing. It is a laboratory rating established at reference test conditions, normally around 25 \u00b0C and standard humidity.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Do not confuse In with Imax. On our <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/product\/br-20dp-2p-20ka-type-3-surge-protector\/\" target=\"_blank\" rel=\"noopener noreferrer\">BR-20DP 2P 20kA Type 3 SPD<\/a>, In is 10 kA while Imax is 20 kA. Imax is the absolute maximum current for a single event; In is the repeated-duty rating that protects your equipment day after day. Both numbers are valid only at the reference temperature under which they were tested.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">For a buyer, the practical question is not whether the datasheet says 10 kA. It is whether that 10 kA survives the real temperature inside your enclosure. The answer, from both component physics and field returns, is that it does not \u2014 not fully, and not forever.<\/p>\r\n<p style=\"margin: 0 0 18px 0; background: #009292; border-radius: 8px; padding: 20px 22px; color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.7;\">Planning a surge protection layout for a hot or enclosed environment? Our engineers will review your panel temperature profile and recommend the right 10kA-class SPD for the job.\r\n<a style=\"display: inline-block; background: #ffffff; color: #009292; padding: 10px 18px; border-radius: 5px; text-decoration: none; font-weight: bold; margin-top: 12px;\" href=\"https:\/\/www.britecelectric.com\/el\/contact-us\/\" target=\"_blank\" rel=\"noopener noreferrer\">Talk to a Britec engineer<\/a><\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">The MOV Physics \u2014 Why Heat Weakens a 10kA SPD<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Almost every low-voltage SPD is built around a metal-oxide varistor (MOV). An MOV is a voltage-dependent resistor: below its clamping threshold it passes almost no current, and above that threshold it conducts strongly to divert a surge to ground. The critical detail is that the varistor voltage has a negative temperature coefficient.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">As the MOV junction temperature rises, its varistor voltage drops. The device therefore begins to conduct at a lower system voltage than it did when cold. Two things follow. First, the leakage (or climbing) current that always flows across the MOV increases. Second, that extra leakage current generates additional self-heating, which drops the varistor voltage further, which increases leakage again. This is a positive feedback loop.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">At the extreme, the loop runs away: the MOV heats faster than it can dissipate, its clamping voltage collapses, and a thermal disconnector must trip to remove it from the circuit. Britec Type 3 devices use a built-in thermal disconnection tripping device with a green\/red status window for exactly this reason. The red window is the proof that the device sacrificed itself rather than let the fault persist.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Even short of thermal runaway, repeated heat cycling ages the varistor. Each hot day slightly lowers its surge capacity and slightly raises its leakage floor. So high operating temperature derates a 10kA SPD in two ways at once: it reduces the instantaneous surge current the device can still absorb, and it shortens the cumulative service life before end-of-life.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">How Much Does a 10kA SPD Derate?<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">The exact derating curve is specific to each varistor design and is published in the product datasheet. The table below is representative guidance for a 10kA-class MOV SPD rated to an operating range of \u221240 \u00b0C to +80 \u00b0C, and it shows the direction and rough magnitude of the effect. Treat it as a planning aid, not a substitute for the datasheet.<\/p>\r\n\r\n<table style=\"border-collapse: collapse; width: 100%; margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 15px; color: #333333;\">\r\n<tbody>\r\n<tr>\r\n<th style=\"background: #009292; color: #ffffff; border: 1px solid #e3e8ef; padding: 10px 12px; text-align: left;\">Operating temperature<\/th>\r\n<th style=\"background: #009292; color: #ffffff; border: 1px solid #e3e8ef; padding: 10px 12px; text-align: left;\">Relative surge capability (illustrative)<\/th>\r\n<th style=\"background: #009292; color: #ffffff; border: 1px solid #e3e8ef; padding: 10px 12px; text-align: left;\">Design note<\/th>\r\n<\/tr>\r\n<tr style=\"background: #f4fbfb;\">\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">\u221225 \u00b0C<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">~105%<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">Cold improves clamping margin<\/td>\r\n<\/tr>\r\n<tr>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">25 \u00b0C (reference)<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">100% (In = 10 kA)<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">Datasheet rating applies<\/td>\r\n<\/tr>\r\n<tr style=\"background: #f4fbfb;\">\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">40 \u00b0C<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">~95%<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">Typical ventilated indoor panel<\/td>\r\n<\/tr>\r\n<tr>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">55 \u00b0C<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">~85%<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">Begin ventilation review<\/td>\r\n<\/tr>\r\n<tr style=\"background: #f4fbfb;\">\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">70 \u00b0C<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">~70%<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">Upsize or actively cool<\/td>\r\n<\/tr>\r\n<tr>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">80 \u00b0C (rated max)<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">~60%<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">At limit; avoid sustained operation<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">The takeaway is simple: a 10kA SPD installed where it regularly runs hot may behave closer to a 7 kA or 6 kA device in real surge events, and it will reach end-of-life sooner than the same unit in a cool panel.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">The IEC 61643 Reference-Test Gap<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">IEC\/EN 61643-11 proves that a device meets its In and Imax at reference conditions. That certification is real and valuable \u2014 it is why Britec units carry TUV, CE and Intertek SEMKO marks. But the standard does not de-rate the rating for a 60 \u00b0C enclosure or a sealed tropical cabinet. The test simply does not model your site.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">That gap is where under-protection hides. A specifier reads 10 kA on the label, assumes 10 kA in the field, and never asks what the enclosure temperature actually is. When the next surge arrives on a hot afternoon, the MOV is already partly derated and the protected equipment pays the difference.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">Where High-Temperature Derating Hits Hardest<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Temperature derating is not a uniform risk. It concentrates in a few installation patterns, and most of them are common in commercial and industrial B2B projects:<\/p>\r\n<p style=\"text-align: center; margin: 0 0 18px 0;\"><img style=\"max-width: 480px; height: auto;\" src=\"https:\/\/www.britecelectric.com\/wp-content\/uploads\/2026\/09\/br20dp-type3-spd-installed-enclosure.webp\" alt=\"BR-20DP Type 3 SPD mounted inside an electrical enclosure where ambient temperature affects performance\" \/><\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Sealed distribution enclosures with little or no ventilation, where heat from breakers and the SPD itself accumulates.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf SPDs mounted adjacent to inverters, variable-frequency drives, transformers or motor control centers that radiate heat continuously.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Tropical, desert or unshaded rooftop sites where ambient air regularly reaches 45 \u00b0C to 55 \u00b0C.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf PV combiner boxes and solar DC cabinets exposed to direct sun, where internal temperature spikes track the panel temperature.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">These are exactly the environments where, as discussed in <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/blog\/why-10ka-spds-are-ideal-for-branch-circuits-in-residential-units\/\" target=\"_blank\" rel=\"noopener noreferrer\">our guide to 10kA SPDs for branch circuits<\/a>, the 10kA class is most often specified \u2014 which makes temperature awareness doubly important.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">How to Specify a 10kA SPD for Hot Environments<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">The good news is that derating is predictable and manageable. Follow these steps when selecting or reviewing a 10kA-class SPD:<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Measure the enclosure worst-case operating temperature, not the room temperature. Solar gain and internal loads can add 20 \u00b0C or more.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Compare that site maximum against the SPD rated operating range. Britec Type 3 units are rated \u221240 \u00b0C to +80 \u00b0C; sustained operation near +80 \u00b0C leaves little margin.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf If the site runs hot, upsize deliberately: choose a higher In and Imax, or a device rated for a wider temperature range, so the derated value still clears your required protection level.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Provide ventilation or spacing headroom; never bury the SPD in an unvented box directly beside a heat source.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Specify devices with a visible green\/red status window and, for critical circuits, optional remote signalling so condition can be monitored without opening the panel.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Build thermal and visual inspection into maintenance, and replace any unit showing a red fault window or elevated leakage.<\/p>\r\n<p style=\"margin: 0 0 18px 0; background: #009292; border-radius: 8px; padding: 20px 22px; color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.7;\">Not sure what temperature your panels actually reach, or which kA rating to specify? Send us your enclosure drawing and site conditions and we will size the SPD correctly.\r\n<a style=\"display: inline-block; background: #ffffff; color: #009292; padding: 10px 18px; border-radius: 5px; text-decoration: none; font-weight: bold; margin-top: 12px;\" href=\"https:\/\/www.britecelectric.com\/el\/contact-us\/\" target=\"_blank\" rel=\"noopener noreferrer\">Request a specification review<\/a><\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">Britec 10kA-Class SPD Options<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Britec offers 10kA-class devices engineered for the operating envelopes above. Two representative options:<\/p>\r\n<p style=\"text-align: center; margin: 0 0 18px 0;\"><a href=\"https:\/\/www.britecelectric.com\/el\/product\/br-20dp-2p-20ka-type-3-surge-protector\/\" target=\"_blank\" rel=\"noopener noreferrer\"><img style=\"max-width: 320px; height: auto; border: 1px solid #e3e8ef;\" src=\"https:\/\/www.britecelectric.com\/wp-content\/uploads\/2026\/10\/britec-br-20dp-2p-type3.webp\" alt=\"BR-20DP 2P 20kA Type 3 SPD with 10kA nominal discharge current\" \/><\/a><\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u039f <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/product\/br-20dp-2p-20ka-type-3-surge-protector\/\" target=\"_blank\" rel=\"noopener noreferrer\">BR-20DP 2P 20kA Type 3 SPD<\/a> is a Class III \/ Type 3 device with Uc of 275 V or 320 V, In of 10 kA (8\/20 \u00b5s), Imax of 20 kA, Up \u2264 1200 V, response time \u2264 25 ns, an operating range of \u221240 \u00b0C to +80 \u00b0C, 35 mm DIN-rail mounting, UL94-V0 housing and IP20 protection. It is suited to the main or sub-distribution board of a low-voltage installation and is available with optional remote signalling.<\/p>\r\n<p style=\"text-align: center; margin: 0 0 18px 0;\"><a href=\"https:\/\/www.britecelectric.com\/el\/product\/br-230-type-3-surge-protector\/\" target=\"_blank\" rel=\"noopener noreferrer\"><img style=\"max-width: 320px; height: auto; border: 1px solid #e3e8ef;\" src=\"https:\/\/www.britecelectric.com\/wp-content\/uploads\/2025\/04\/Type-3-Surge-Protector.webp\" alt=\"Britec Type 3 surge protector BR-T3, 10kA-class protection for terminal equipment\" \/><\/a><\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u039f <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/product\/br-230-type-3-surge-protector\/\" target=\"_blank\" rel=\"noopener noreferrer\">BR-T3 Type 3 surge protector<\/a> is a compact terminal-equipment protector in the same 10kA class, ideal for the point-of-use layer close to sensitive loads. Both sit within our broader family of <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/product-category\/ac-power-surge-protection\/\" target=\"_blank\" rel=\"noopener noreferrer\">AC surge protection devices<\/a>, where higher In\/Imax Type 2 units can be selected when the site demands more headroom against heat derating.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">\u03a3\u03c5\u03c7\u03bd\u03ad\u03c2 \u0395\u03c1\u03c9\u03c4\u03ae\u03c3\u03b5\u03b9\u03c2<\/h2>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">Does a 10kA SPD really lose surge capacity in heat?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Yes. The metal-oxide varistor has a negative temperature coefficient, so higher operating temperature lowers its clamping voltage, raises leakage current and reduces the surge current it can still absorb. The 10 kA rating is a reference-temperature value, not a constant field value.<\/p>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">At what temperature does derating become significant?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Minor effects appear above about 40 \u00b0C, become material around 55 \u00b0C to 70 \u00b0C, and reach roughly 40% loss of relative capability near the +80 \u00b0C upper rating. The precise curve is in each product datasheet.<\/p>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">Is Imax (20 kA) also affected by temperature?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Yes. Both In and Imax are reference-condition ratings. A higher Imax gives more single-event headroom, but it does not make the device immune to heat; it simply starts from a larger number before derating.<\/p>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">How do I know if my SPD has been heat-damaged?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Watch the status window: a red indicator means the thermal disconnector has tripped and the module should be replaced. For gradual ageing, optional remote signalling can report leakage trends before a hard fault occurs.<\/p>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">Should I choose a higher kA rating for hot sites?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Often yes. If the enclosure runs hot, specifying a higher In and Imax means the derated value still meets your protection requirement. Pair the upsize with ventilation and a temperature-aware layout rather than relying on the datasheet number alone.<\/p>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">Does IEC 61643 certification cover high-temperature operation?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Certification confirms the device meets In\/Imax at reference test conditions. It does not re-rate the product for a hot enclosure. The standard proves the design; it does not override the physics of temperature derating on site.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">\u03a3\u03cd\u03bd\u03b1\u03c8\u03b7<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">A 10kA SPD is only a 10kA SPD at its rated temperature. In hot, enclosed or sun-exposed installations the real capability can fall well below the label, and service life shortens accordingly. Specify from the enclosure temperature up, give the device ventilation and headroom, monitor its status, and choose a rating that survives derating \u2014 not just one that looks right on paper.<\/p>\r\n<p style=\"margin: 0 0 18px 0; background: #009292; border-radius: 8px; padding: 20px 22px; color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.7;\">Get a site-specific SPD recommendation that accounts for your real operating temperature. Our team will match the right 10kA-class device to your panel and climate.\r\n<a style=\"display: inline-block; background: #ffffff; color: #009292; padding: 10px 18px; border-radius: 5px; text-decoration: none; font-weight: bold; margin-top: 12px;\" href=\"https:\/\/www.britecelectric.com\/el\/contact-us\/\" target=\"_blank\" rel=\"noopener noreferrer\">Contact Britec for a quote<\/a><\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">Related Resources<\/h2>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/blog\/why-10ka-spds-are-ideal-for-branch-circuits-in-residential-units\/\" target=\"_blank\" rel=\"noopener noreferrer\">Why 10kA SPDs Are Ideal for Branch Circuits<\/a> \u2014 where the 10kA class fits in a layered protection scheme.<\/p>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/blog\/ac-surge-protective-device-failure-causes-and-solutions\/\" target=\"_blank\" rel=\"noopener noreferrer\">Common AC Surge Protective Device Failure Causes and Solutions<\/a> \u2014 how heat, ageing and faults end an SPD.<\/p>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/blog\/type-3-surge-protective-device-selection-guide\/\" target=\"_blank\" rel=\"noopener noreferrer\">Type 3 Surge Protective Device Selection Guide<\/a> \u2014 matching Type 3 devices to sensitive loads.<\/p>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/blog\/what-causes-solar-dc-spds-to-overheat-or-fail-prematurely\/\" target=\"_blank\" rel=\"noopener noreferrer\">What Causes Solar DC SPDs to Overheat or Fail Prematurely<\/a> \u2014 the heat-failure mechanism in PV enclosures.<\/p>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/blog\/spd-surge-protective-device-maximum-continuous-operating-voltage-uc-explained\/\" target=\"_blank\" rel=\"noopener noreferrer\">SPD Maximum Continuous Operating Voltage (Uc) Explained<\/a> \u2014 why Uc must clear your system and temperature profile.<\/p>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/el\/blog\/4-pole-spd-maintenance-guide-for-electrical-systems\/\" target=\"_blank\" rel=\"noopener noreferrer\">4 Pole SPD Maintenance Guide for Electrical Systems<\/a> \u2014 inspection steps that catch heat ageing early.<\/p>","protected":false},"featured_media":2706,"parent":0,"menu_order":5,"template":"","meta":{"_acf_changed":false},"blog_category":[9],"class_list":["post-2722","blog","type-blog","status-publish","has-post-thumbnail","hentry","blog_category-industry-news"],"acf":{"des":"A field guide to why elevated operating temperatures derate a 10kA SPD's surge capacity and service life, the MOV derating mechanism, IEC 61643 limits, and how to specify SPDs for hot sites.","txt":"<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Reviewed by the Britec Electric engineering team. Britec Electric, based in Wenzhou, Zhejiang, China, has manufactured surge protective devices (SPDs) since 2003. Our products are tested and certified to IEC\/EN 61643-11 by TUV, CE and Intertek SEMKO. Drawing on that field experience, this guide explains why a 10kA SPD loses part of its rated performance as its operating temperature climbs \u2014 and what specifiers and installers should do about it.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">What 10kA Actually Means on an SPD<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">When a manufacturer labels a device a 10kA SPD, the number refers to its nominal discharge current, written In, measured with the 8\/20 \u00b5s current waveform defined in IEC\/EN 61643-11. In is the surge current the SPD can absorb repeatedly \u2014 typically a sequence of standardized 8\/20 \u00b5s strikes \u2014 without failing. It is a laboratory rating established at reference test conditions, normally around 25 \u00b0C and standard humidity.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Do not confuse In with Imax. On our <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/product\/br-20dp-2p-20ka-type-3-surge-protector\/\" target=\"_blank\" rel=\"noopener noreferrer\">BR-20DP 2P 20kA Type 3 SPD<\/a>, In is 10 kA while Imax is 20 kA. Imax is the absolute maximum current for a single event; In is the repeated-duty rating that protects your equipment day after day. Both numbers are valid only at the reference temperature under which they were tested.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">For a buyer, the practical question is not whether the datasheet says 10 kA. It is whether that 10 kA survives the real temperature inside your enclosure. The answer, from both component physics and field returns, is that it does not \u2014 not fully, and not forever.<\/p>\r\n<p style=\"margin: 0 0 18px 0; background: #009292; border-radius: 8px; padding: 20px 22px; color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.7;\">Planning a surge protection layout for a hot or enclosed environment? Our engineers will review your panel temperature profile and recommend the right 10kA-class SPD for the job.\r\n<a style=\"display: inline-block; background: #ffffff; color: #009292; padding: 10px 18px; border-radius: 5px; text-decoration: none; font-weight: bold; margin-top: 12px;\" href=\"https:\/\/www.britecelectric.com\/contact-us\/\" target=\"_blank\" rel=\"noopener noreferrer\">Talk to a Britec engineer<\/a><\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">The MOV Physics \u2014 Why Heat Weakens a 10kA SPD<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Almost every low-voltage SPD is built around a metal-oxide varistor (MOV). An MOV is a voltage-dependent resistor: below its clamping threshold it passes almost no current, and above that threshold it conducts strongly to divert a surge to ground. The critical detail is that the varistor voltage has a negative temperature coefficient.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">As the MOV junction temperature rises, its varistor voltage drops. The device therefore begins to conduct at a lower system voltage than it did when cold. Two things follow. First, the leakage (or climbing) current that always flows across the MOV increases. Second, that extra leakage current generates additional self-heating, which drops the varistor voltage further, which increases leakage again. This is a positive feedback loop.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">At the extreme, the loop runs away: the MOV heats faster than it can dissipate, its clamping voltage collapses, and a thermal disconnector must trip to remove it from the circuit. Britec Type 3 devices use a built-in thermal disconnection tripping device with a green\/red status window for exactly this reason. The red window is the proof that the device sacrificed itself rather than let the fault persist.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Even short of thermal runaway, repeated heat cycling ages the varistor. Each hot day slightly lowers its surge capacity and slightly raises its leakage floor. So high operating temperature derates a 10kA SPD in two ways at once: it reduces the instantaneous surge current the device can still absorb, and it shortens the cumulative service life before end-of-life.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">How Much Does a 10kA SPD Derate?<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">The exact derating curve is specific to each varistor design and is published in the product datasheet. The table below is representative guidance for a 10kA-class MOV SPD rated to an operating range of \u221240 \u00b0C to +80 \u00b0C, and it shows the direction and rough magnitude of the effect. Treat it as a planning aid, not a substitute for the datasheet.<\/p>\r\n\r\n<table style=\"border-collapse: collapse; width: 100%; margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 15px; color: #333333;\">\r\n<tbody>\r\n<tr>\r\n<th style=\"background: #009292; color: #ffffff; border: 1px solid #e3e8ef; padding: 10px 12px; text-align: left;\">Operating temperature<\/th>\r\n<th style=\"background: #009292; color: #ffffff; border: 1px solid #e3e8ef; padding: 10px 12px; text-align: left;\">Relative surge capability (illustrative)<\/th>\r\n<th style=\"background: #009292; color: #ffffff; border: 1px solid #e3e8ef; padding: 10px 12px; text-align: left;\">Design note<\/th>\r\n<\/tr>\r\n<tr style=\"background: #f4fbfb;\">\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">\u221225 \u00b0C<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">~105%<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">Cold improves clamping margin<\/td>\r\n<\/tr>\r\n<tr>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">25 \u00b0C (reference)<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">100% (In = 10 kA)<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">Datasheet rating applies<\/td>\r\n<\/tr>\r\n<tr style=\"background: #f4fbfb;\">\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">40 \u00b0C<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">~95%<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">Typical ventilated indoor panel<\/td>\r\n<\/tr>\r\n<tr>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">55 \u00b0C<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">~85%<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">Begin ventilation review<\/td>\r\n<\/tr>\r\n<tr style=\"background: #f4fbfb;\">\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">70 \u00b0C<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">~70%<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">Upsize or actively cool<\/td>\r\n<\/tr>\r\n<tr>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">80 \u00b0C (rated max)<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">~60%<\/td>\r\n<td style=\"border: 1px solid #e3e8ef; padding: 10px 12px;\">At limit; avoid sustained operation<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">The takeaway is simple: a 10kA SPD installed where it regularly runs hot may behave closer to a 7 kA or 6 kA device in real surge events, and it will reach end-of-life sooner than the same unit in a cool panel.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">The IEC 61643 Reference-Test Gap<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">IEC\/EN 61643-11 proves that a device meets its In and Imax at reference conditions. That certification is real and valuable \u2014 it is why Britec units carry TUV, CE and Intertek SEMKO marks. But the standard does not de-rate the rating for a 60 \u00b0C enclosure or a sealed tropical cabinet. The test simply does not model your site.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">That gap is where under-protection hides. A specifier reads 10 kA on the label, assumes 10 kA in the field, and never asks what the enclosure temperature actually is. When the next surge arrives on a hot afternoon, the MOV is already partly derated and the protected equipment pays the difference.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">Where High-Temperature Derating Hits Hardest<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Temperature derating is not a uniform risk. It concentrates in a few installation patterns, and most of them are common in commercial and industrial B2B projects:<\/p>\r\n<p style=\"text-align: center; margin: 0 0 18px 0;\"><img style=\"max-width: 480px; height: auto;\" src=\"https:\/\/www.britecelectric.com\/wp-content\/uploads\/2026\/09\/br20dp-type3-spd-installed-enclosure.webp\" alt=\"BR-20DP Type 3 SPD mounted inside an electrical enclosure where ambient temperature affects performance\" \/><\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Sealed distribution enclosures with little or no ventilation, where heat from breakers and the SPD itself accumulates.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf SPDs mounted adjacent to inverters, variable-frequency drives, transformers or motor control centers that radiate heat continuously.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Tropical, desert or unshaded rooftop sites where ambient air regularly reaches 45 \u00b0C to 55 \u00b0C.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf PV combiner boxes and solar DC cabinets exposed to direct sun, where internal temperature spikes track the panel temperature.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">These are exactly the environments where, as discussed in <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/blog\/why-10ka-spds-are-ideal-for-branch-circuits-in-residential-units\/\" target=\"_blank\" rel=\"noopener noreferrer\">our guide to 10kA SPDs for branch circuits<\/a>, the 10kA class is most often specified \u2014 which makes temperature awareness doubly important.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">How to Specify a 10kA SPD for Hot Environments<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">The good news is that derating is predictable and manageable. Follow these steps when selecting or reviewing a 10kA-class SPD:<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Measure the enclosure worst-case operating temperature, not the room temperature. Solar gain and internal loads can add 20 \u00b0C or more.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Compare that site maximum against the SPD rated operating range. Britec Type 3 units are rated \u221240 \u00b0C to +80 \u00b0C; sustained operation near +80 \u00b0C leaves little margin.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf If the site runs hot, upsize deliberately: choose a higher In and Imax, or a device rated for a wider temperature range, so the derated value still clears your required protection level.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Provide ventilation or spacing headroom; never bury the SPD in an unvented box directly beside a heat source.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Specify devices with a visible green\/red status window and, for critical circuits, optional remote signalling so condition can be monitored without opening the panel.<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf Build thermal and visual inspection into maintenance, and replace any unit showing a red fault window or elevated leakage.<\/p>\r\n<p style=\"margin: 0 0 18px 0; background: #009292; border-radius: 8px; padding: 20px 22px; color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.7;\">Not sure what temperature your panels actually reach, or which kA rating to specify? Send us your enclosure drawing and site conditions and we will size the SPD correctly.\r\n<a style=\"display: inline-block; background: #ffffff; color: #009292; padding: 10px 18px; border-radius: 5px; text-decoration: none; font-weight: bold; margin-top: 12px;\" href=\"https:\/\/www.britecelectric.com\/contact-us\/\" target=\"_blank\" rel=\"noopener noreferrer\">Request a specification review<\/a><\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">Britec 10kA-Class SPD Options<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Britec offers 10kA-class devices engineered for the operating envelopes above. Two representative options:<\/p>\r\n<p style=\"text-align: center; margin: 0 0 18px 0;\"><a href=\"https:\/\/www.britecelectric.com\/product\/br-20dp-2p-20ka-type-3-surge-protector\/\" target=\"_blank\" rel=\"noopener noreferrer\"><img style=\"max-width: 320px; height: auto; border: 1px solid #e3e8ef;\" src=\"https:\/\/www.britecelectric.com\/wp-content\/uploads\/2026\/10\/britec-br-20dp-2p-type3.webp\" alt=\"BR-20DP 2P 20kA Type 3 SPD with 10kA nominal discharge current\" \/><\/a><\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">The <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/product\/br-20dp-2p-20ka-type-3-surge-protector\/\" target=\"_blank\" rel=\"noopener noreferrer\">BR-20DP 2P 20kA Type 3 SPD<\/a> is a Class III \/ Type 3 device with Uc of 275 V or 320 V, In of 10 kA (8\/20 \u00b5s), Imax of 20 kA, Up \u2264 1200 V, response time \u2264 25 ns, an operating range of \u221240 \u00b0C to +80 \u00b0C, 35 mm DIN-rail mounting, UL94-V0 housing and IP20 protection. It is suited to the main or sub-distribution board of a low-voltage installation and is available with optional remote signalling.<\/p>\r\n<p style=\"text-align: center; margin: 0 0 18px 0;\"><a href=\"https:\/\/www.britecelectric.com\/product\/br-230-type-3-surge-protector\/\" target=\"_blank\" rel=\"noopener noreferrer\"><img style=\"max-width: 320px; height: auto; border: 1px solid #e3e8ef;\" src=\"https:\/\/www.britecelectric.com\/wp-content\/uploads\/2025\/04\/Type-3-Surge-Protector.webp\" alt=\"Britec Type 3 surge protector BR-T3, 10kA-class protection for terminal equipment\" \/><\/a><\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">The <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/product\/br-230-type-3-surge-protector\/\" target=\"_blank\" rel=\"noopener noreferrer\">BR-T3 Type 3 surge protector<\/a> is a compact terminal-equipment protector in the same 10kA class, ideal for the point-of-use layer close to sensitive loads. Both sit within our broader family of <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/product-category\/ac-power-surge-protection\/\" target=\"_blank\" rel=\"noopener noreferrer\">AC surge protection devices<\/a>, where higher In\/Imax Type 2 units can be selected when the site demands more headroom against heat derating.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">Frequently Asked Questions<\/h2>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">Does a 10kA SPD really lose surge capacity in heat?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Yes. The metal-oxide varistor has a negative temperature coefficient, so higher operating temperature lowers its clamping voltage, raises leakage current and reduces the surge current it can still absorb. The 10 kA rating is a reference-temperature value, not a constant field value.<\/p>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">At what temperature does derating become significant?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Minor effects appear above about 40 \u00b0C, become material around 55 \u00b0C to 70 \u00b0C, and reach roughly 40% loss of relative capability near the +80 \u00b0C upper rating. The precise curve is in each product datasheet.<\/p>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">Is Imax (20 kA) also affected by temperature?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Yes. Both In and Imax are reference-condition ratings. A higher Imax gives more single-event headroom, but it does not make the device immune to heat; it simply starts from a larger number before derating.<\/p>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">How do I know if my SPD has been heat-damaged?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Watch the status window: a red indicator means the thermal disconnector has tripped and the module should be replaced. For gradual ageing, optional remote signalling can report leakage trends before a hard fault occurs.<\/p>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">Should I choose a higher kA rating for hot sites?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Often yes. If the enclosure runs hot, specifying a higher In and Imax means the derated value still meets your protection requirement. Pair the upsize with ventilation and a temperature-aware layout rather than relying on the datasheet number alone.<\/p>\r\n<p style=\"margin: 14px 0 4px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #1a1a1a; font-weight: bold;\">Does IEC 61643 certification cover high-temperature operation?<\/p>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">Certification confirms the device meets In\/Imax at reference test conditions. It does not re-rate the product for a hot enclosure. The standard proves the design; it does not override the physics of temperature derating on site.<\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">Conclusion<\/h2>\r\n<p style=\"margin: 0 0 18px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">A 10kA SPD is only a 10kA SPD at its rated temperature. In hot, enclosed or sun-exposed installations the real capability can fall well below the label, and service life shortens accordingly. Specify from the enclosure temperature up, give the device ventilation and headroom, monitor its status, and choose a rating that survives derating \u2014 not just one that looks right on paper.<\/p>\r\n<p style=\"margin: 0 0 18px 0; background: #009292; border-radius: 8px; padding: 20px 22px; color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.7;\">Get a site-specific SPD recommendation that accounts for your real operating temperature. Our team will match the right 10kA-class device to your panel and climate.\r\n<a style=\"display: inline-block; background: #ffffff; color: #009292; padding: 10px 18px; border-radius: 5px; text-decoration: none; font-weight: bold; margin-top: 12px;\" href=\"https:\/\/www.britecelectric.com\/contact-us\/\" target=\"_blank\" rel=\"noopener noreferrer\">Contact Britec for a quote<\/a><\/p>\r\n\r\n<h2 style=\"font-family: Arial,Helvetica,sans-serif; font-size: 24px; color: #1a1a1a; margin: 28px 0 12px 0; border-bottom: 2px solid #009292; padding-bottom: 6px;\">Related Resources<\/h2>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/blog\/why-10ka-spds-are-ideal-for-branch-circuits-in-residential-units\/\" target=\"_blank\" rel=\"noopener noreferrer\">Why 10kA SPDs Are Ideal for Branch Circuits<\/a> \u2014 where the 10kA class fits in a layered protection scheme.<\/p>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/blog\/ac-surge-protective-device-failure-causes-and-solutions\/\" target=\"_blank\" rel=\"noopener noreferrer\">Common AC Surge Protective Device Failure Causes and Solutions<\/a> \u2014 how heat, ageing and faults end an SPD.<\/p>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/blog\/type-3-surge-protective-device-selection-guide\/\" target=\"_blank\" rel=\"noopener noreferrer\">Type 3 Surge Protective Device Selection Guide<\/a> \u2014 matching Type 3 devices to sensitive loads.<\/p>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/blog\/what-causes-solar-dc-spds-to-overheat-or-fail-prematurely\/\" target=\"_blank\" rel=\"noopener noreferrer\">What Causes Solar DC SPDs to Overheat or Fail Prematurely<\/a> \u2014 the heat-failure mechanism in PV enclosures.<\/p>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/blog\/spd-surge-protective-device-maximum-continuous-operating-voltage-uc-explained\/\" target=\"_blank\" rel=\"noopener noreferrer\">SPD Maximum Continuous Operating Voltage (Uc) Explained<\/a> \u2014 why Uc must clear your system and temperature profile.<\/p>\r\n<p style=\"margin: 0 0 6px 0; font-family: Arial,Helvetica,sans-serif; font-size: 16px; line-height: 1.8; color: #333333;\">\u25cf <a style=\"color: #009292; text-decoration: underline;\" href=\"https:\/\/www.britecelectric.com\/blog\/4-pole-spd-maintenance-guide-for-electrical-systems\/\" target=\"_blank\" rel=\"noopener noreferrer\">4 Pole SPD Maintenance Guide for Electrical Systems<\/a> \u2014 inspection steps that catch heat ageing early.<\/p>"},"_links":{"self":[{"href":"https:\/\/www.britecelectric.com\/el\/wp-json\/wp\/v2\/blog\/2722","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.britecelectric.com\/el\/wp-json\/wp\/v2\/blog"}],"about":[{"href":"https:\/\/www.britecelectric.com\/el\/wp-json\/wp\/v2\/types\/blog"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.britecelectric.com\/el\/wp-json\/wp\/v2\/media\/2706"}],"wp:attachment":[{"href":"https:\/\/www.britecelectric.com\/el\/wp-json\/wp\/v2\/media?parent=2722"}],"wp:term":[{"taxonomy":"blog_category","embeddable":true,"href":"https:\/\/www.britecelectric.com\/el\/wp-json\/wp\/v2\/blog_category?post=2722"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}