RCBO Problem

[Bez]

Second fixed a new lighting circuit today

4 pendants off a dimmer

2 GU10's off a dimmer

3 GU10's off 1 gang

2 GU10's off 1 gang 2 way

R1+R2 0.50 ohms

IR >299 Mohms

All was going well till I got to the board. Installed a shiny new out of the box 6A MK RCBO.

Problem No. 1 RCBO Tripped when fridge kicked in,reset ok (fridge is on new ring that I installed, completely seperate)

Problem No. 2 Kept tripping on Zs Test (NO Trip selected)

Problem No. 3 Did RCD Test at Board, RCBO refused to trip on

or

.

Have connected circuit to old MCB so client can have some lighting

(Zs was 0.92 ohms when done through MCB)

Is the RCBO up the creek or am I missing something

 

[Andy™]

did you test the RCBO in isolation (remove all outgoing conductors)?

 

[Bez]

[quote name='Andy

 

[batty]

I had one a while back tested out OK to start but then started tripping out randomly when tested second time was up the creak so replaced and all is OK now. Luckily was at a neighbors so did not have to go far to fix it and that was an MK one.

Batty

 

[Bez]

The most puzzling is why trip when the fridge kicks in, is there some kind of back current up the neutral fly lead if they're faulty?

 

[safedepth]

Of course No 3 means it's faulty and fails and so needs replacing anyway but No2 reminds me of a fault I was told about. Tripping characteristics on Type B MCB's/RCBO's is about 6x rating. Current injected could trip a 6A breaker. This could of course could be me remembering rubbish.

 

[PIP IOM]

this may have been my post, RCBO's/MCB's tripping when testing Zs using my 6 yr old Megger 1502. Bought 1553 (ouch) and all OK now.

 

[Bez]

this may have been my post, RCBO's/MCB's tripping when testing Zs using my 6 yr old Megger 1502. Bought 1553 (ouch) and all OK now.

This one was tripping and the 1552 was still in the van:O

 

[Andy™]

This one was tripping and the 1552 was still in the van:O

i didnt realise my 1552 could test whilst its still in the van!

do you think that it could sit in the back of the van & test whilst shouting the results to me sitting in the warm cab writing EIC/PIR