Cicuit breaker with GFCI

Have a spa protected by a 30 Amp, 230 V, GFCI breaker which I'm pretty sure was bad, so I replaced it.

Question(s):

Tested old one with ohm meter which shows open. Am I getting a good test? (Literature with new one says both sides must be energized for GFCI to work)

If not a good test, how can I check old one?

Also, is above described breaker available in "designed for switching"?

Given the cost of this breaker, I was wondering how many duty cycles they are designed to handle when used as a switch. The recommendation is to check them every thirty days.

In other words, since the old breaker probably had no more than one hundred (100) on/off cycles over a span of six (6) years, why did it fail?

Thanks in advance.

Reply to
Ace
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| Tested old one with ohm meter which shows open. Am I getting a good test? | (Literature with new one says both sides must be energized for GFCI to work)

An ohm meter is only going to tell you if the contacts are closed. I've never heard of a GFCI breaker that won't close unenergized, but that doesn't mean there aren't any.

| If not a good test, how can I check old one?

You really need to test its ground fault detection circuitry. There are testers that do this. If you have to rig one up, a nice way to do this would be to have a box that has the ability to switch in and out a few different milliamp current levels for leakage detection. These would be connected between the hot phase (or phases) and ground (not neutral) through an appropriate resistor. The design would depend on your electrical system. If you are in Europe with 230 volt single phase, it could simply have 3 switches that each control a 115k ohm 1 watt resistor. This would give you the ability to choose 2ma, 4ma, and 6ma of leakage current. I might do it with 6 switches for 1ma increments and maybe go to a higher level of leakage just to see if its an out of spec detection. This assume your standards for leakage current are 2 to 6 milliamps as here in the USA.

Testing its overcurrent protection is harder to do and riskier. Some day I want to rig something up like that myself. But I'd never recommend that to anyone (EEs qualified to do so will know that they are).

| Also, is above described breaker available in "designed for switching"? | | Given the cost of this breaker, I was wondering how many duty cycles they | are | designed to handle when used as a switch. The recommendation is to check | them | every thirty days.

My understanding is breakers in this range can handle 1000 cycles or more. This should give you 83 years of monthly testing.

| In other words, since the old breaker probably had no more than one hundred | (100) | on/off cycles over a span of six (6) years, why did it fail?

That's unknown at this point.

Reply to
phil-news-nospam

We have RCDs in UK which will not close in some supply fault conditions, such as broken neutral, neutral/hot reversed. The ones I'm familiar with will close unenergized, but will open on these fault conditions.

We have plug-in RCDs which will not close unenergized and will trip on loss of power. They are intended for power tools where having them unexpectedly start up on supply restoration might be a hazard. Effectively a no-volts trip.

No, RCD ratings in UK are most commonly 30mA, with 10mA and 100mA being other values you will less commonly see (and higher values for larger commercial installations).

I built a tester many years ago. It works as you describe, with leakage settings of 5ma, 10ma, 15ma, 30ma. Our rules require that an RCD must not trip at half its rating (test limited to 2 seconds max for safety reasons), and must trip at 100% of its rating within some time which I forget (200ms? but they're normally very much faster than that). The 5/10/15/30ma settings allow testing of 10ma and 30ma RCDs at 50% and 100% trip ratings.

Reply to
Andrew Gabriel

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