Rcd fails test.

[jelly belly]

Hi, I've been installing a new shower, using a shower consumer unit complete with rcd. All the tests passed, r1 And r2 were 0.23 ohms, insulation resistance was >299M ohms, polarity was correct. But when I test the rcd I cannot get it to trip. It passes when the test button is pressed but will not pass the rcd test at 1 or 5 times, it fails to trip and my tester says time exceeded and shuts off.
Every thing appears correct I ran out of time so have isolated it the shower and will investigate it again tomorrow.

all advice would be appreciated.

thanks

 

[KAS1]

1,How familiar are you with your test equipment 2, at what point in the circuit did you preform the tests on the RCD, 3 what do you mean you ran out of time, you should know by now electricians can make time lol

 

[onions1066]

I had this the other day on a 100ma rcd and I forgot to change the tester and left it on 30ma test. You sure you haven't changed your range by accident.?

 

[jelly belly]

I'm familiar with my tester, I ran the test at both at the shower end of the circuit and the consumer unit end. I had to pack up due to child care issues otherwise I would have spent longer longer looking for the fault. To double check my tester I checked the properties other rcd using the socket tester and it worked as it should, so I'm certain my tester is ok. I was using the testers leads to test the shower circuit.

- - - Updated - - -

I checked tester was set to 30mA

 

[onions1066]

Rcd fooooooooked then.

 

[jelly belly]

Onions, thanks for that, that was what I was thinking, i was beginning to think I had missed something. But as the r1 and r2 and insulation tests are ok there shouldn't be a damage to the cable. I checked all connections were tight in both the shower and the switch unit.

 

[jelly belly]

Time to remove rcd and return it to supplier and get a new one and the cost of a forty mile trip.

 

[trev]

Rcd fooooooooked then.

Nice to see the correct terminology being used.

 

[Guitarist]

The test button simply introduces an imbalance coil to test the mechanism is working, so this won't help. Just out of interest, before you return the unit, have you tried using the leads in exactly the same way on your known "good" RCD, or did you use the plug adaptor? Just a thought in case you had something connected incorrectly in this instance.

 

[telectrix]

swap the RCDs round. see if the problem shifts .

 

[Megavolt]

Time to remove rcd and return it to supplier and get a new one and the cost of a forty mile trip.

good luck with that. Never managed to get them to sump up when I have tried

 

[Octopus]

40 mile round trip, where the hell do you live?

 

[oldtimer]

If its a BG CU then same happened to me

 

[GLENNSPARK]

Rcd fooooooooked then.

no...more like you fooooked up again.....
what the hells a 100mA RCD got to do with a shower?...

 

[jelly belly]

Hi, live in northern Scotland, hence distance to supplier, nothing is close by. It's a Wyler shower cu.

 

[domn]

one thing to check is that you have not put your meter onto test a dc rcd i was having the same thing on a job took me bloody ages to realize.

dom

 

[Hawkmoon]

Onions, thanks for that, that was what I was thinking, i was beginning to think I had missed something. But as the r1 and r2 and insulation tests are ok there shouldn't be a damage to the cable. I checked all connections were tight in both the shower and the switch unit.

Zs test at shower would have confirmed your earth was good without the rechecking of all your connections (as you already done r1 & r2)

You said you checked the other RCD with the plug attachment - I would check both RCDs, at the board, with the leads - if one trips and the other doesn't then as Onions said......

 

[tony mc]

Hi, I've been installing a new shower, using a shower consumer unit complete with rcd. All the tests passed, r1 And r2 were 0.23 ohms, insulation resistance was >299M ohms, polarity was correct. But when I test the rcd I cannot get it to trip. It passes when the test button is pressed but will not pass the rcd test at 1 or 5 times, it fails to trip and my tester says time exceeded and shuts off.
Every thing appears correct I ran out of time so have isolated it the shower and will investigate it again tomorrow.

all advice would be appreciated.

thanks

You have not mentioned ZS! I take it your shower unit has a ZE /Ra ?

 

[jelly belly]

Ze is 0.13 and zs for shower is 0.38.

 

[jelly belly]

Hawk moon, I will try your suggestion tomorrow, I've got to prove rcd, either is duff or that there a fault elsewhere.
Thanks to everyone for all the advice, as always it's helpful.