RCD tripping at half the rating ?

[Kev2632]

Hello, i was doing an RCD test yesterday on half its rating, and the rcd kept tripping everytime, does this mean the RCD is faulty?

 

[chrish_1977]

Did you carry out a ramp test to see what it is actually tripping at

 

[pete555]

it is faulty and requires replacing

 

[bigbaddave]

Did you have anything pluged in at the time or was it off load?

 

[chrish_1977]

it is faulty and requires replacing

Couldn't be anything else then?

 

[Kev2632]

yea i did the ramp test and it tripped out at 17ma :s, there was some things plugged in at the time of the test happening yea?

 

[Octopus]

Best test it again with all MCB's switched off to get a better idea. It could well need replacing - they are not as reliable as people think

 

[Kev2632]

how can you do a RCD test when all the MCB's are switched off?

 

[jamesBoater]

An RCD should trip no less than 50% of its rating?

 

[i=p/u]

Test at terminals of rcd

 

[Kev2632]

Test at terminals of rcd

oh ok yea, i didnt know if that was possible? i take it that is still ok to do yea?

 

[bigbaddave]

yea i did the ramp test and it tripped out at 17ma :s, there was some things plugged in at the time of the test happening yea?

It could be giving a bad reading then, For Example the things you still have connected could be producing earth leakage..

Therefore if its leaking 5ma then the 17 its tripping at will man 23ma

As above retest at RCD with no MCB'S ON

 

[JD6400]

oh ok yea, i didnt know if that was possible? i take it that is still ok to do yea?

Have they started teaching a different way to test a rcd now days then ?

 

[Sintra]

oh ok yea, i didnt know if that was possible? i take it that is still ok to do yea?

That is the correct test procedure for an RCD. Test at device with no loads connected.

 

[JD6400]

Thanks Sintra , was starting to wonder what latest fad they had changed things to this time !

 

[telectrix]

it's these 5 week courses. week 6 is when they were going to mention placing probes on live terminals.

 

[guest119]

Have they started teaching a different way to test a rcd now days then ?

electrical trainee shortform course :dunce2:.

Boydy

 

[pete555]

Couldn't be anything else then?

of course but why mess change it and cure it

 

[shagbite]

of course but why mess change it and cure it

you're confusing me.

are you saying that changing the rcd will cure the fault, even if the rcd isn't the cause of the fault?

 

[bigbaddave]

Sounds like is