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Cicuit breaker with GFCI

A

Ace

Jan 1, 1970
0
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.
 
A

Andrew Gabriel

Jan 1, 1970
0
| 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.

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.
| 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.

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.
 
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