RCD test results

Talk Electrician Forum

Help Support Talk Electrician Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

MalcyB

Senior Member
Joined
Oct 3, 2008
Messages
317
Reaction score
0
HI all.

I tested an RCD yesterday and got these results.

1/2x 300ms

1/2x 300ms

1x 203ms

1x 11ms

5x 11ms

5x 19ms

Could anyone tell me a reason why the 1st 1x delta test is so high?

Thanks

Malc

 
No I didn't the guy was running late and I had to leave.

No it didn't trip on the 1/2.

 
HI all.I tested an RCD yesterday and got these results.

1/2x 300ms

1/2x 300ms

1x 203ms

1x 11ms

5x 11ms

5x 19ms

Could anyone tell me a reason why the 1st 1x delta test is so high?

Thanks

Malc
These results are not unusual, you should always take readings...[as you did]

at least two times.[i personally go for a third ]..usually on 180 degree Phase shift.....Sticky switching mechanisms problems are then eliminated.

 
These results are not unusual, you should always take readings...[as you did]at least two times.[i personally go for a third ]..usually on 180 degree Phase shift.....Sticky switching mechanisms problems are then eliminated.
All I will say is that you only get one chance for the RCD to trip in the event of a fault!!

IMO.... if it doesn't trip the first time (within limits) then it's a fail

:coat

 
All I will say is that you only get one chance for the RCD to trip in the event of a fault!!IMO.... if it doesn't trip the first time (within limits) then it's a fail

:coat
Dont agree with that one NOZ ! Sometimes these RCDs have not been operated for years and after a couple of trip tests they are back to spec.

if people tested them Quarterly ,as recommended, then it wouldnt be a problem,in practice this doesnt happen ,but following the trip testing its back within spec as the test meter results verify .

 
Dont agree with that one NOZ ! Sometimes these RCDs have not been operated for years and after a couple of trip tests they are back to spec.if people tested them Quarterly ,as recommended, then it wouldnt be a problem,in practice this doesnt happen ,but following the trip testing its back within spec as the test meter results verify .
But in real life what is actually going to happen? If it's not tested and it doesn't disconnect in time someone could die.

 
But in real life what is actually going to happen? If it's not tested and it doesn't disconnect in time someone could die.
but the problem being, in real life, RCD's should be tested regularly. which should avoid the problem of sticking. but people dont do this, so it may not operate when needed. what we need is an RCD that works like an MCB, in that it doesnt need tested (or open/closed) often

 
but the problem being, in real life, RCD's should be tested regularly. which should avoid the problem of sticking. but people dont do this, so it may not operate when needed. what we need is an RCD that works like an MCB, in that it doesnt need tested (or open/closed) often
This is why I am not happy with the 17th edition regs being so heavily reliant on RCD's and less reliant on supplementary bonding.

 
Thanks for the answers.

I will be going back there on Tuesday so I will do the test again and compare results.

The board is an older wylex board with the rcd protecting all the curcuits.

Malc

 
I do not like the fact that a RCD that is used as additional protection "may" fail simply because the reccomended testing intervals are not adhered to.

I have rcd's in my home been there for about 10 years now, tested? NEVER. and I am an electrician. If you work from home I suppose your monthly checks for calibration would test the rcd's, but if you work from an office or unit then the tests are carried out there.

People will not carry out the checks, often although the information is provided they will forget, or simply not bother, there is then a risk that under a fault the rcd will NOT operate within the required time.

If this where to happen, and god forbid a fatality occured, who would be to blame?

Unfortunately it would be the owner, because the manufacturer of the rcd will undoubtedly say, because the required testing was not carried out, failure is down to the owners.

I think this is shamefull.

 
but the problem being, in real life, RCD's should be tested regularly. which should avoid the problem of sticking. but people don't do this, so it may not operate when needed. what we need is an RCD that works like an MCB, in that it doesn't need tested (or open/closed) often
Who says mcb don't fail the only reason we know rcd fail because we can test them with meters and a test button, how do we test mcb's we don't we just hope they work

 
I will just apply my 50amp short circuit tester cable across the shower circuit....Boom, flash, spark!!!! :eek: :D:^O:^O:^O:^O
ill just add to that.....

Boom, flash, spark!!!! Blackout!!!

well, not always, been on a job before when drilling through the feed didnt blow 300A fuse, and neither did cutting through it live (stupid DNO bloke! i told him it was live, but no, he knows best!)

 
Went back today and the rcd tested fine.

Thanks for all the replys.

Malc

 
Dont agree with that one NOZ ! Sometimes these RCDs have not been operated for years and after a couple of trip tests they are back to spec.if people tested them Quarterly ,as recommended, then it wouldnt be a problem,in practice this doesnt happen ,but following the trip testing its back within spec as the test meter results verify .
:D

 
Top