{"id":797,"date":"2023-12-19T16:31:05","date_gmt":"2023-12-19T08:31:05","guid":{"rendered":"https:\/\/www.britecelectric.com\/?post_type=blog&p=797"},"modified":"2024-09-05T16:36:33","modified_gmt":"2024-09-05T08:36:33","slug":"surge-protector-faq","status":"publish","type":"blog","link":"https:\/\/www.britecelectric.com\/sv\/blog\/surge-protector-faq\/","title":{"rendered":"Vanliga fr\u00e5gor om \u00f6versp\u00e4nningsskydd"},"content":{"rendered":"H\u00e5ller \u00f6versp\u00e4nningsskydd f\u00f6r evigt?<\/strong>\r\n\r\nNej, det g\u00f6r de inte. Varje g\u00e5ng ett \u00f6versp\u00e4nningsskydd dirigerar om en str\u00f6m\u00f6versp\u00e4nning bort fr\u00e5n din anslutna utrustning, tar den interna strukturen av skyddet lite skada. Med tiden slutar de delar av \u00f6versp\u00e4nningsskyddet som h\u00e5ller din anslutna utrustning helt enkelt att fungera. Hur l\u00e5ng tid detta tar beror p\u00e5 frekvensen och styrkan av str\u00f6mst\u00f6tar.\r\n\r\n\u00c4r de befintliga skydden som MCB, ELCB etc. inte tillr\u00e4ckliga f\u00f6r att skydda mot \u00f6versp\u00e4nningar?<\/strong>\r\n\r\nAll the existing protecting devices like MCB, ELCB etc. are current sensitive devices. They get activated based on a fault current. These devices are triggered when the fault current persists for duration of more than 3 to 20 milliseconds. However, the surge typically lasts for a few micro seconds only during which time it causes all the damage.\r\n\r\nHence the conventional devices like MCB, ELCB fuses etc. are not effective in protection against surges. In view of the above, special equipment called surge protection device which has a response time of two nanoseconds is required to be installed to protect against the surges.\r\n\r\nVad \u00e4r en str\u00f6mst\u00f6t?<\/strong>\r\n\r\nEn str\u00f6mst\u00f6t \u00e4r en topp i den elektriska str\u00f6mmen som flyter genom kablarna i ditt hus. De kan skada vanliga apparater, k\u00e4nslig AV-elektronik och datorutrustning.\r\n\r\nVilka olika tekniker anv\u00e4nds i SPD:er?<\/strong>\r\n\r\nN\u00e5gra av de popul\u00e4ra teknikerna som anv\u00e4nds i SPD:er \u00e4r f\u00f6ljande:\r\n
    \r\n \t
  1. i) Gasurladdningsr\u00f6r<\/li>\r\n \t
  2. ii) Metalloxidvaristorer<\/li>\r\n<\/ol>\r\niii) Gnistgap\r\n
      \r\n \t
    1. iv) Zenerdiod<\/li>\r\n \t
    2. v) Silicon Avalanche dioder<\/li>\r\n<\/ol>\r\nBland dessa \u00e4r gasurladdningsr\u00f6r, metalloxidvaristorer och gnistgap de mest popul\u00e4ra typerna av \u00f6versp\u00e4nningsavledare.\r\n\r\nVad orsakar en str\u00f6mst\u00f6rning?<\/strong>\r\n\r\nDe flesta str\u00f6mst\u00f6rningar kommer inifr\u00e5n ditt hem. \u00d6versp\u00e4nningar orsakas av m\u00e5nga olika faktorer, inklusive h\u00e5rt v\u00e4der, felaktiga eller skadade elektriska ledningar eller pl\u00f6tslig p\u00e5slagning och avst\u00e4ngning av en h\u00f6geffekts elektrisk enhet som en luftkonditionering eller en stor elmotor.\r\n\r\nSka SPD-klassificeringarna v\u00e4ljas beroende p\u00e5 linjestr\u00f6mmen?<\/strong>\r\n\r\nGenerellt \u00e4r SPD:erna installerade p\u00e5 den elektriska str\u00f6mkretsen parallellkopplade och kommer d\u00e4rf\u00f6r att vara oberoende av belastningsstr\u00f6m (linje).\r\n\r\nVarf\u00f6r oroa sig f\u00f6r str\u00f6mst\u00f6rningar?<\/strong>\r\n\r\nKraftiga str\u00f6mst\u00f6rningar kan utpl\u00e5na din hemutrustning p\u00e5 ett \u00f6gonblick. F\u00f6rutom \u00f6versp\u00e4nningar orsakade av stormar, kan det genomsnittliga hemmet uppleva flera \u201cdolda\u201d \u00f6versp\u00e4nningar om dagen fr\u00e5n andra olika k\u00e4llor. Dessa mindre \u00f6versp\u00e4nningar orsakar kumulativa skador p\u00e5 elektroniken, f\u00f6rkortar deras livsl\u00e4ngd och g\u00f6r s\u00e5 sm\u00e5ningom att de misslyckas.\r\n\r\nHur avg\u00f6r man vilka typer av SPD:er som ska installeras p\u00e5 en given plats?<\/strong>\r\n\r\nValet av SPD p\u00e5 en given plats beror p\u00e5:\r\n
        \r\n \t
      1. a) Platsens topografi i form av blixtnedslag.<\/li>\r\n \t
      2. b) Mottaglighet f\u00f6r v\u00e4xlingsst\u00f6tar vad g\u00e4ller n\u00e4rhet till stora belastningar \/ ansluten till landsbygdsmatare etc.<\/li>\r\n \t
      3. c) K\u00e4nslighet hos den utrustning som \u00e4r ansluten till kretsen.<\/li>\r\n<\/ol>\r\nNormally SPDs with Class-B & C are installed at the main panels and SPDs with Class-C rate are installed at the sub panels. The ratings for class-B, SPDs shall be a minimum of 12.5 KA Iimp.\r\n\r\nFor the Class-C (Imax. rating), it should be, a minimum of 40 kA at the sub panels.\r\n\r\nFor the Class-D SPDs which are installed near sensitive equipment, the criteria shall be the residual voltage or the protection level which should be lower than the temporary over voltage withstanding capacity of the protected equipment.\r\n\r\nVad g\u00f6r ett \u00f6versp\u00e4nningsskydd?<\/strong>\r\n\r\nEtt \u00f6versp\u00e4nningsskydd skyddar elektroniken fr\u00e5n de skadliga effekterna av \u00f6versp\u00e4nningar och sp\u00e4nningsspikar. \u00d6versp\u00e4nningsskydd kan absorbera och avleda kraften fr\u00e5n en \u00f6versp\u00e4nning s\u00e5 att ansluten utrustning skyddas fr\u00e5n \u00f6versp\u00e4nningen.\r\n\r\nHur vet man att den installerade SPD:n fungerar?<\/strong>\r\n\r\nEftersom SPD:erna alltid \u00e4r parallellkopplade med den elektriska kretsen \u00e4r det under normalf\u00f6rloppet inte m\u00f6jligt att veta om de \u00e4r i fungerande skick eller inte. D\u00e4rf\u00f6r \u00e4r det n\u00f6dv\u00e4ndigt att ha en lokal och fj\u00e4rrindikation med hj\u00e4lp av elektrisk kontakt f\u00f6r att k\u00e4nna till och \u00f6vervaka h\u00e4lsan hos SPD.\r\n\r\n\u00c4r det n\u00f6dv\u00e4ndigt att ha separat jordning f\u00f6r SPD:er?<\/strong>\r\n\r\nDet \u00e4r inte n\u00f6dv\u00e4ndigt att ha en separat eller dedikerad jordning f\u00f6r SPD:er. SPD:erna ska alltid vara anslutna till det allm\u00e4nna jordn\u00e4tet.\r\n\r\n\u00c4r ett bra jordningssystem n\u00f6dv\u00e4ndigt f\u00f6r att SPD ska fungera effektivt?<\/strong>\r\n\r\nAlla SPD fungerar genom att avleda \u00f6verskottsenergin till marken. D\u00e4rf\u00f6r \u00e4r det absolut n\u00f6dv\u00e4ndigt att jordningssystemet som \u00e4r anslutet till SPD:n m\u00e5ste vara i effektivt fungerande skick s\u00e5 att \u00f6versp\u00e4nningsstr\u00f6mmen kan flyta till jorden utan n\u00e5gra hinder.\r\n\r\nFinns SPD:er tillg\u00e4ngliga f\u00f6r andra till\u00e4mpningar \u00e4n den elektriska kretsen som telefonlinjer, datalinjer etc.?<\/strong>\r\n\r\nSPD:er \u00e4r s\u00e4kert tillg\u00e4ngliga f\u00f6r varje krets som telefonlinjer, datalinjer, Ethernet-linjer, signallinjer etc. I alla dessa kretsar \u00e4r SPD:er seriekopplade.\r\n\r\n\u00c4r enbart prim\u00e4ra SPD:er tillr\u00e4ckliga f\u00f6r utrustningsskydd?<\/strong>\r\n\r\nNej, fr\u00e5n en liten anl\u00e4ggning till en stor anl\u00e4ggning \u00e4r det vanligtvis n\u00f6dv\u00e4ndigt att anv\u00e4nda en kaskad- eller skiktad strategi d\u00e4r prim\u00e4rt skydd \u00e4r installerat vid serviceentr\u00e9panelen och sekund\u00e4rt skydd vid grenpaneler. Varje anl\u00e4ggning kr\u00e4ver individuell analys f\u00f6r att fastst\u00e4lla r\u00e4tt skydd f\u00f6r att m\u00f6ta behoven hos den utrustning som anv\u00e4nds. Det kan till och med vara n\u00f6dv\u00e4ndigt att inkludera ytterligare punkt-of-use SPD om denna utrustning \u00e4r placerad en bit fr\u00e5n den f\u00f6rs\u00f6rjningspanelen. Ett kaskad tillv\u00e4gag\u00e5ngss\u00e4ttrekommenderas av IEEE och denna typ av tillv\u00e4gag\u00e5ngss\u00e4tt kommer att ge det mest effektiva \u00f6versp\u00e4nningsskyddet i hela en anl\u00e4ggning. F\u00f6r mer information om var du ska till\u00e4mpa SPD:er, v\u00e4lj den typ av milj\u00f6 du \u00e4r intresserad av: industri, kommersiell eller bostadsmilj\u00f6.\r\n\r\nVarf\u00f6r beh\u00f6ver jag en SPD n\u00e4r jag redan har en isoleringstransformator?<\/strong>\r\n\r\nIsolationstransformatorer ger mycket bra avst\u00f6tning av normalmod men ger inte bra differentiell (normal) avst\u00e4ngning. Med andra ord, en \u00f6versp\u00e4nning som \u00f6verlagras lika p\u00e5 b\u00e5de linje (L) och neutral (N) ledare kommer att se avvisande av isoleringstransformatorn, medan en \u00f6versp\u00e4nning som upptr\u00e4der differentiellt mellan L- och N-ledarna kommer att passera genom transformatorn. T\u00e4nk ocks\u00e5 p\u00e5 att majoriteten av transienterna genereras av belastningarna inom anl\u00e4ggningen, p\u00e5 belastningssidan av dessatransformatorer. F\u00f6r att minimera effekterna av dessa internt genererade transienter fr\u00e5n en utrustning till en annan b\u00f6r en SPD placeras.","protected":false},"featured_media":798,"parent":0,"menu_order":176,"template":"","meta":{"_acf_changed":false},"blog_category":[8],"class_list":["post-797","blog","type-blog","status-publish","has-post-thumbnail","hentry","blog_category-company-news"],"acf":{"des":"Do surge protectors last forever?No, they do not. Each time a surge protector reroutes a power surge away from your connected equipment, the internal structure of the protector takes a little bit of damage.","txt":"Do surge protectors last forever?<\/strong>\r\n\r\nNo, they do not. Each time a surge protector reroutes a power surge away from your connected equipment, the internal structure of the protector takes a little bit of damage. Over time the parts of the surge protector that keep your connected equipment safe simply stop working. How long this takes depends on the frequency and strength of power surges.\r\n\r\nAre the existing protections like MCB, ELCB etc. not sufficient to protect against surges?<\/strong>\r\n\r\nAll the existing protecting devices like MCB, ELCB etc. are current sensitive devices. They get activated based on a fault current. These devices are triggered when the fault current persists for duration of more than 3 to 20 milliseconds. However, the surge typically lasts for a few micro seconds only during which time it causes all the damage.\r\n\r\nHence the conventional devices like MCB, ELCB fuses etc. are not effective in protection against surges. In view of the above, special equipment called surge protection device which has a response time of two nanoseconds is required to be installed to protect against the surges.\r\n\r\nWhat is a power surge?<\/strong>\r\n\r\nA power surge is a spike in the electrical current flowing through the wires of your house. They can damage common appliances, sensitive AV electronics and computer equipment.\r\n\r\nWhat are the different technologies used in SPDs?<\/strong>\r\n\r\nSome of the popular technologies used in SPDs are the following:\r\n
          \r\n \t
        1. i) Gas discharge tubes<\/li>\r\n \t
        2. ii) Metal oxide varistors<\/li>\r\n<\/ol>\r\niii) Spark gap\r\n
            \r\n \t
          1. iv) Zener diode<\/li>\r\n \t
          2. v) Silicon Avalanche diodes<\/li>\r\n<\/ol>\r\nAmong these, gas discharge tubes, metal oxide varistors and spark gap are the most popular types of surge arresters.\r\n\r\nWhat causes a power surge?<\/strong>\r\n\r\nMost power surges stem from inside your home. Power surges are caused by many different factors, including severe weather, faulty or damaged electric wiring or the sudden turning on and off of a high power electrical device like an air conditioner or large electric motor.\r\n\r\nAre the SPDs ratings to be selected depending on the line current?<\/strong>\r\n\r\nGenerally, the SPDs installed on the electrical Power circuit are connected in parallel and hence will be independent of load (line) current.\r\n\r\nWhy worry about power surges?<\/strong>\r\n\r\nStrong power surges can wipe out your home equipment in an instant. In addition to surges caused by storms, the average home can experience multiple \u201chidden\u201d surges a day from other various sources. These smaller surges cause cumulative damage to electronics, shortening their life and eventually causing them to fail.\r\n\r\nHow to determine what types of SPDs are to be installed at a given location?<\/strong>\r\n\r\nThe selection of SPDs at a given location depends on:\r\n
              \r\n \t
            1. a) The topography of the location in terms of lightning strikes.<\/li>\r\n \t
            2. b) Susceptibility to switching surges in terms of proximity to large loads \/ connected to rural feeder etc.<\/li>\r\n \t
            3. c) Sensitivity of the equipment connected to the circuit.<\/li>\r\n<\/ol>\r\nNormally SPDs with Class-B & C are installed at the main panels and SPDs with Class-C rate are installed at the sub panels. The ratings for class-B, SPDs shall be a minimum of 12.5 KA Iimp.\r\n\r\nFor the Class-C (Imax. rating), it should be, a minimum of 40 kA at the sub panels.\r\n\r\nFor the Class-D SPDs which are installed near sensitive equipment, the criteria shall be the residual voltage or the protection level which should be lower than the temporary over voltage withstanding capacity of the protected equipment.\r\n\r\nWhat does a surge protector do?<\/strong>\r\n\r\nA surge protector safeguards electronics from the harmful effects of power surges and voltage spikes. Surge protectors can absorb and dissipate the power of a surge so that connected equipment is shielded from the surge.\r\n\r\nHow does one know the SPD installed is working?<\/strong>\r\n\r\nSince the SPDs are always connected in parallel to the electrical circuit, during the normal course it is not possible to know whether they are in working condition or not. Hence it is necessary to have a local and remote indication using electrical contact in order to know and monitor the healthiness of the SPD.\r\n\r\nIs it necessary for having separate grounding for SPDs?<\/strong>\r\n\r\nIt is not necessary to have a separate or dedicated grounding for SPDs. The SPDs should always be connected to the general earth grid.\r\n\r\nIs a good earthing system necessary for efficient working of the SPD?<\/strong>\r\n\r\nAll SPDs work by diverting the excess energy to the ground. Hence it is imperative that the earthing system connected to the SPD must be in efficient working condition so that the surge current can flow to the earth without any hindrance.\r\n\r\nAre SPDs available for applications other than the electrical circuit like telephone lines, data lines etc.?<\/strong>\r\n\r\nSPDs are certainly available for every circuit like telephone lines, data lines, Ethernet lines, signal lines etc. In all these circuits SPDs are connected in series.\r\n\r\nAre primary SPDs alone sufficient for equipment protection?<\/strong>\r\n\r\nNo, from a small facility to a large facility, it is usually necessary to adopt a cascaded or layered approach where primary protection is installed at the service entrance panel, and secondary protection at branch panels. Each facility requires individual analysis to determine the right protection to meet the needs of the equipment being used. It can even be necessary to include additional point-of-use SPDs if this equipment is located some distance from the supplying panel. A cascaded approach is recommended by the IEEE and this type of approach will provide the most effective surge protection throughout a facility. For more information on where to apply SPDs, select the type of environment you\u2019re interested in: industrial, commercial, or residential.\r\n\r\nWhy do I need an SPD when I already have an isolation transformer?<\/strong>\r\n\r\nIsolation transformers provide very good common mode rejection but do not provide good differential (normal) mode rejection. In other words, a surge superimposed equally on both the line (L) and neutral (N) conductors will see rejection by the isolation transformer, while a surge appearing differentially between the L and N conductors will pass through the transformer. Also, keep in mind the majority of transients are being generated by the loads within the facility, on the load side of these transformers. To minimize the effects of these internally generated transients from one piece of equipment to another an SPD should be placed."},"_links":{"self":[{"href":"https:\/\/www.britecelectric.com\/sv\/wp-json\/wp\/v2\/blog\/797","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.britecelectric.com\/sv\/wp-json\/wp\/v2\/blog"}],"about":[{"href":"https:\/\/www.britecelectric.com\/sv\/wp-json\/wp\/v2\/types\/blog"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.britecelectric.com\/sv\/wp-json\/wp\/v2\/media\/798"}],"wp:attachment":[{"href":"https:\/\/www.britecelectric.com\/sv\/wp-json\/wp\/v2\/media?parent=797"}],"wp:term":[{"taxonomy":"blog_category","embeddable":true,"href":"https:\/\/www.britecelectric.com\/sv\/wp-json\/wp\/v2\/blog_category?post=797"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}