EICR Code for working RCD with non-functioning test button

[Andy78]

Was the test button function tested with outgoing circuits disconnected ? I've had connected N-E faults stop the test button working before.

 

[pc1966]

Was the test button function tested with outgoing circuits disconnected ? I've had connected N-E faults stop the test button working before.

That is an interesting point, the N-E background current could be opposite to the test button's current, not enough to trip frequencly itself, but enough to block the test!

But I would expect the MTF test to show that as failure at 'In' (similar to button) but pass at '5In' (where plenty of current to oppose the N-E fault)?

 

[Dartlec]

Was the test button function tested with outgoing circuits disconnected ? I've had connected N-E faults stop the test button working before.

I'm fairly sure i did yes, though now this thread has me doubting myself - its possible I did it with lives disconnected (via mcb) but not neutrals. Only one circuit in this case, kitchen sockets - and washing machine socket was not accessible.

I have run into cases before where the test button won't work with loads connected. (I believe some washing machines can cause strange things to happen?) so I normally ensure that all circuits are off when I test the button.

Though that then begs a further question - should the notice to press the test button add that it should be tested with all loads disconnected? If the test button doesn't work with loads connected then surely we're back to a potential C2, even if it works once they are disconnected??

 

[pc1966]

I suspect all cases of "test button not working" should be investigated.

Usually leakage L-E is going to be pretty much in-phase with the internal test button so if anything would make it more sensitive to trip, but as already mentioned a N-E fault could cause odd behaviour without always tripping. Normally though you see other loads going on/off causing a spurious trip in that case.

One reason I like the Wylex/Crabtree compact RCBO is the isolation of load L & N when off so it is simple to test for leakage without pulling out wires, etc.

 

[magnoliafan89]

Meter first, test button last, this is because if you have a sticky or slow rcd, the test button could free it up before you test, and you would never know that there was an inherent problem. That's what I was taught anyway

Interesting. I was taught press test button reset test with meter and then when done with thay just check meter hasnt broken it so press test button again

 

[Welchyboy1]

to save all the faff of paperwork, I'd replace both the RCD and the associated MCB with,say, BG devices. cost about £20. Then it would not be mix & match.

Thats exactly what i would of done, your effectively only using the LAP housing then
[automerge]1595611244[/automerge]
I would C3 probably

Whats the rest of the install like ?

 

[telectrix]

Thats exactly what i would of done, your effectively only using the LAP housing then

a box is a box. when i shuffle this mortal coil, i don't care if they put me in a £500 coffin with velvet lining, or a plain box made from an old Ikea wardrobe. both will burn at a similar rate.

 

[Dartlec]

a box is a box. when i shuffle this mortal coil, i don't care if they put me in a £500 coffin with velvet lining, or a plain box made from an old Ikea wardrobe. both will burn at a similar rate.

What about an 18th edition coffin though, that would hopefully burn a little slower....

 

[Pauls0212]

I had this on a recent eicr, and was about to swap out the rcd until I tried the button with a screwdriver and it tripped, must have been some dust in the way and my fat fingers couldnt press it in hard enough. After the trip with screwy my fingers worked it, must have pressed it about 20 times during the eicr as i didnt trust it., but all fine now. I also retested about 5 times on auto to make sure.

 

[Dartlec]

I would C3 probably

Whats the rest of the install like ?

Ironically the rest of the install while a lot older was the easiest EICR I've had for a while.

The main CU is one of the Wylex skeleton boards in a built in meter cupboard from 70s or 80s(?) with the nasty plastic front that you have to wriggle out, Type 2 MCBs and a 100mA RCD.

Last time I checked there is no easy direct replacement for them - though a full external replacement would definitely be the best option. However, nothing there that earned less than a C3 (only 3 sockets in 2 upstairs bedrooms, 8 lights in the whole house and a connected but unused immersion and oven feed)