Lightning arrester testing

[Dave A]

Any ideas on how to test that a lightning arrester is still working?

[tec0]

Well you get a lot of lighting arresters. In the aria where I live we get massif lighting strikes, sometimes so powerful that they take out the power in really no time at all. I think it’s because of all the dust. So unplugging everything is probably your only bet.

So the real question is what type of lighting arrester are you using at the moment?

[garthu]

A key and a kite were the first thing that came to mind

Are we talking domestic TV type stuff?? The easiest is visual. If the MOV's are not damaged/cracked etc..they then it should be fine. If the MOV's have any continuity they are stuffed.

Only other way is get a current limited AC supply 300V variac or such and see if it starts limiting at around 250V (or the MOV's limits)

Fence lightning protectors are if theres any continuity, its stuffed.

[Dave A]

This would be the type that goes into an electrical distribution board.

[AndyD]

Are they general purpose surge protectors?

Some surge arrestors have an indicator led (or neon) which lights up if they need replacement.

[Dave A]

All the ones I've seen have an indicator of some sort. Of course not being on the service end that also means I haven't seen many

Maybe I'm second guessing this or it's a broken telegraph problem, but the term used was "test" the lightning arresters. Now I took that as something different from running around checking the indicators. But I could be wrong.

Do you think those indicators are reliable?

[AndyD]

The end of life indicators on a DB mounted surge arrestor should be a reliable indicator. The cheap and nasty five into one trailing adapters with surge protection are a different story, I wouldn't trust those as far as I could throw them.

Actual testing of surge arrestors is a little tricky. You need to know the clamping voltage and what type of arrestor it is. Also running a surge arrestor above the clamping voltage, even in a short test, can in itself cause the device to break down irreparably.

MOS type arrestors should really be replaced as a matter of course when they reach 7-8 years of service. They are extremely sensitive to moisture and tend to have reached the end of their reliability at around this time.

Thermal imagery can be use for the larger arrestors used in power transmission systems but I'm not sure if it would be effective for the small DIN mounted devices in a DB. Maybe Murdock or QuintonIR could clarify further.

The definitive answer would be to consult the manufacturers literature for that model of device.

[Master Electrician]

According to CBI (Circuit Breaker Industries) if the indicator is off when the power is on, the unit is stuffed.