Differences in AC mains surge protection? - Page 1
Forum section: electronics / general

author: Halcyon
author_rank: Unknown
timestamp: August 09, 2016, 06:12:15 am
content: I'm looking at a number of different surge protection devices for my network terminator (which connects my house to the external public network).At the end of the day, I don't mind so much if my NTD gets fried with a surge up the AC mains, I just want to limit damage to that device (and not the rest of my network infrastructure).My question is, what are the differences between a regular surge protector and those with an $xx,xxx guarantee against connected equipment? I'm assuming both have MOVs? Is one device actually better than the other or are you basically just paying for an insurance premium?Take these two for example:Belkin BSV102Belkin F9A100One is guaranteed for up to $15,000 connected equipment warranty and the other $40,000 (the latter has far more specs listed than the first).

author: karoru
author_rank: Regular Contributor
timestamp: August 09, 2016, 08:03:30 am
content: I don't really believe in these pluggable surge protectors - they won't even tell which class they are in their specs. Not to mention data given in specs are pure nonsense - you qualify surge protection devices via voltage it takes to turn them on, not maximal voltage spike they can withstand without evacuating magic smoke. And how can you treat seriously device that claimsQuoteThere are two main types of surge protectors (I don't want to go too much into naming classes and so because it will depend on your country local regulations) - ones with spark gaps and ones with MOVs, transils and so on.Spark gap ones (called "type 1", "class B" or something similar) will start conducting at higher voltage than MOV ones ("type 2" or "class C"). These pluggable ones are usually called "class D" and they won't help at any serious lightning incident, they can only help with sensitive devices if connected AFTER proper surge protector of class B or C.So if you want a proper solution, you have to get class B, C or B+C surge protector at your electrical box and (if you want) small plugable one just before your device.Refer to your local regulations for the type of surge protector recommended, but the rule of thumb is - if you have lightning rod or any other similar installation on your house, then you need B or B+C (because type B is made to withstand direct lightning strike), and if you don't then type C is sufficient (because there is no big risk of direct lightning strike, and arrestors on the grid will do the rough job if lightning strikes on the line somewhere else).That insurance for $40000 is just a marketing flick, most people have lightning incidents with appliances once per few years at best, and nobody will connect any really expensive device to 30$ gizmo and think it makes appliance immortal;)

author: Halcyon
author_rank: Unknown
timestamp: August 09, 2016, 08:13:22 am
content: I looked at "whole house" surge protection and most electricians looked at me funny. In any case, such solutions in Australia seem very few and far between unless we're talking about data centres. For a home, it looks like it would cost me quite a bit to implement (probably more than the equipment it was protecting). Lightning rods aren't common in Australia with the exception of high-rise buildings, antenna towers etc...I have a bunch of power boards which actually have MOVs in them (no idea which class they fit in here). But for where my NTD is, it's not practical to have an entire power board, a single socket will do.

author: karoru
author_rank: Regular Contributor
timestamp: August 09, 2016, 08:30:36 am
content: Well, either these power boards or single sockets will withstand a small surge, but in real lightning case they will die horribly. To be honest single-phase type 2 surge protectors (DIN-mountable) cost around 20 euro here in Europe, and type 2+3 (that includes the "very sensitive device" protection) around 50, probably similar pricing in Australia, so it ain't that expensive;) You can even just wire your NTD via it directly.Yeah, I know, most sparkies look at you funny when you speak about whole house solution (despite the fact it doesn't cost that much, really!), but most sparkies also wouldn't install RCDs if it wasn't required by law. Sometimes it's hard to discuss with old professionals that started their career by drilling holes in asbestos and cutting wire for fuses, or young professionals that were being taught by them.