RCD issues

Mark T · Post by **Mark T** » Wed May 01, 2024 3:11 pm

I am not an electrician and will not be carrying out this work myself but need some idea of why the following is happening.

I have an RCD tripping issue that I cannot isolate by turning off circuits.

This is what I have
Main house DB
100A RCD
2 ring main circuits
2 lighting circuits B6
1 hob and extractor circuit B40 only supplying induction hob and extractor.
I shed circuit B40 supplying another DB with 63A main switch
1 garage circuit supplying another DB with 63 A main switch

With all circuits on main DB on use hob RCD trips.
With all circuits on main DB on use anything in garage RCD trips
Turn hob circuit off can use garage no tripping.
Turn garage off can use hob no tripping.

Any ideas folks?

stevei · Post by **stevei** » Wed May 01, 2024 6:51 pm

A photo of your consumer unit showing the RCD and MCBs would help.

Neelix · Post by **Neelix** » Wed May 01, 2024 9:12 pm

Any recent changes?

TBH you really need eyes on site than random advice over the internet.

Your main issue appears to be the single 100 mA RCD which isn’t an ideal,configuration to start with

ericmark · Post by **ericmark** » Thu May 02, 2024 6:56 pm

I use one of these

: Diffrence line neutral 8 Feb 24 reduced.jpg (9.73 KiB) Viewed 408 times

it measures the current showing the difference between the lives, note both lives, line and neutral are in the jaws.

There are other tools, the insulation tester can also show likely leakage, although it uses DC and our homes use AC so not accurate.

The problem is you have a build up of leakages, and what really is needed is RCBO's on each circuit rather than a RCD covering all, but when RCD's first came out we did not have the option of using RCBO's.

But the problem is the clamp on or the insulation tester cost around £35 each for the cheapest, and once cured you may never use them again, so is it worth DIY?

ericmark · Post by **ericmark** » Thu May 02, 2024 7:00 pm

Neelix wrote: ↑Wed May 01, 2024 9:12 pm Your main issue appears to be the single 100 mA RCD which isn’t an ideal,configuration to start with

Where does he say it is a 100 mA RCD? It may well be 100 mA but it could be 30 mA and as to if type AC, A, F, or B no idea. It is at the moment an unknown. Unless there was a answer since deleted?