Tripping Rcd.

[Alex10]

Had a boiler tripping the Rcd. With all parts disconnected. Ie pump, spark gen fan gas vlv etc etc.

1,The boiler was powered up via a fuse spur, now if I was to have all parts disconnected leaving just the Pcb in place and the main earth to the metal case the Rcd trips off. Now if I remove the earth from the case of the boiler it's fine. The Rcd does not trip.

2,Just so I could be sure I wired the boiler via an extension lead onto the next door neighbours house and it was find no problem.


3, when I disconnected the fly lead from the fuse spur completely turned on Rcd it was also fine:/

4. The fuse spur was spurred off a socket I checked this sock with my socket and see and all was ok also all resistance to earth readinging where above 1 mega ohm. And short circuit check was OL.

Am lost, I know it's a neutral to earth fault but what? Help!!!'n
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[PrenticeBoyofDerry]

What happens if you take the PCB out of circuit?

 

[EFLImpudence]

3, when I disconnected the fly lead from the fuse spur completely turned on Rcd it was also fine:/

If the actual CPC(earth) is attached to the back-box with the fly-lead from there to the FCU then that would be the same as disconnecting the CPC from the boiler carcass as you have done.

Is that the case?

 

[Alex10]

Hi gents,

Pcb Replaced first thing I done & wiring harness!

Then got me tools out! Yes mate I completely disconnected the earth as we'll from the boiler and it's ok once that earth goes into the boiler Rcd trips😔

 

[PrenticeBoyofDerry]

But if you have PCB out of circuit does RCD trip, then if you have the PCB unloaded by boiler parts does it trip?

 

[Alex10]

It only trips when the earth from the fuse spur touchs the boiler case! I think!!

With the Pcb fitted and the live Neutral Earth connected to the Pcb via a plug In connection and all parts disconnected and the main earth from boiler case it does not trip. However if I say hold a earth spade to the boiler case or a part it trips off!

I don't think this is a boiler fault as it works fine plugged into next doors but wat the hell could cause this!!

 

[PrenticeBoyofDerry]

Have you tried a Ramp test on RCD?
If the boiler is a spurred from another circuit, try taking everything else off load, so if socket circuit unplug everything and open circuit any other FCUs on circuit. Then try boiler.

 

[flyingsparks]

Does next door have an RCD and does it work?

 

[Alex10]

Yes mate.

Am at a loss with it tbh!

 

[RF Lighting]

Stop powering up stuff without an earth and call an electrician before you kill someone ffs.

 

[Alex10]

One of your crowd put this on my toes! I told him it's not the boiler. He never originally connected the earths at the board when he changed it the cheeky sod! He ran out of ideas and called the manufacturer.

 

[ban-all-sheds]

He never originally connected the earths at the board when he changed it

He wasn't an electrician.

 

[Alex10]

He was !! He just thought **** that am not getting involved here. Probably a six week effort!