DIY Trainees Question Only????

pennychew · Feb 11, 2015

They must have put the wiires back in the wrong terminals on at least one of the sockets, maybe the upstairs ring has new and old colour wiring to confuse them a bit more! I'd do a visual of the sockets connections first as well

Jamie · Feb 15, 2015

Unplug anything in that socket circuit (if anything), buzz or insulation test between L-E/L-N

If it is not clear (probably won't be), disconnect one leg of the circuit at C/U and break the ring at a mid-way point in the socket ring, so the ends are disconnected and in theory makes two radial circuits.

Energize one leg (obviously the open ends at the socket would be terminated separately so they aren't just hanging), if it pops off then you know it's on that energized leg, then try the other leg and see which sockets are on with plug in tester . Start unscrewing ones that are not energized and visual inspection for incorrect termination/squashed cables/nicked cables etc etc

That is how i did a fault the other week with socket rcbo keep tripping, find offending socket and turned out to be L-E as live was poorly terminated (a lot of copper showing outside of terminal) and touching the metal back box causing it to trip off.

Paul.M · Feb 15, 2015

Please dont try to find a fault by energizing the circuit. This fault can be found by dead testing and you pretty much explained it Jamie.

What do you all think about this DIY question, would you like to see more of this type of thread?

pennychew · Feb 15, 2015

Paul.M said:
Please dont try to find a fault by energizing the circuit. This fault can be found by dead testing and you pretty much explained it Jamie.

What do you all think about this DIY question, would you like to see more of this type of thread?

Definitely would, gets you thinking and a good way to learn some fault finding techniques

Paul.M · Feb 15, 2015

I'm looking through the DIY section to find an appropriate thread. If any other Mentor sees one, give me a shout.

amckay · Feb 16, 2015

I'd stat by a visual check of terminations in all of the outlets. The MCB was not tripping before the accessories were changed therefore I suspect that the diyer did something wrong.
However if the diyer is mistaking an RCD or rcbo for a mcb then its possible its a neutral caught between the backbox and accessory screw

newtothis · Feb 16, 2015

I'm pretty sure I know the answer to the problem

May I ask this related question ?

Should we assume if the MCB trips on a circuit protected by an RCD it's a problem with the CPC
Based on RCD detecting imbalances between L + N
Or am I talking a load of BS ?

Pete999 · Feb 16, 2015

newtothis said:
I'm pretty sure I know the answer to the problem

May I ask this related question ?

Should we assume if the MCB trips on a circuit protected by an RCD it's a problem with the CPC
Based on RCD detecting imbalances between L + N
Or am I talking a load of BS ?

Not necessarily a problem with the cpc itself, but think along the lines of what you said about an imbalance between L&N what would cause an imbalance (if it is an RCD tripping) if it's a CB tripping what would cause that? Sorry if I'm going over old ground.