RCD Tripping on different circuits.

[highspark]

Strange one here. I installed a garage installation about 6 months ago. few sockets and lights etc. fed from a sub board. Sub board is fed by 32 amp breaker on 30ma RCD side of board. Original board is a single RCD board. I did not touch the main board as the sub board and feed where already installed by another spark and were suffficient for the addtions.I have returned to same job but working on the attic now. ..........................................................................................................There has been no problems at all with garage since I left. In the loft there was another sub board feeding again lights and sockets. However I needed to put in a new 4 way board in order to incorporate underfloor heating in attic en-suit. When I did the calcs the original MCB supplying the attic was too small and needed to be changed from a 32amp to 40 amp in order to protect additional underfloor heating circuit.When I changed MCB I noticed the down stairs sockets (which I hadn't worked on) started to trip RCD. Anyhow after abit of jiggling about in the board that stopped.......................................................................................................................................................................... I carried on with installation and as I powered up "TRIP AGAIN" I located the trip this time to the garage sockets when neutrals touched neutral bar tripping. In the end I took most the sockets apart and could't get any poor reading etc. When I put everything back tripping had stopped and everything was back to normal. I made a mental note in my head that I did not want to open that main board again as there is an intemitent fault on the RCD side.Got another call today RCD tripped in conservatory when the hoover was plugged in. I'm seriously thinking dodgy RCD that needs to be replaced. Or maybe splitting the load of other circuits across two RCD's in a dual RCD board. By the way there is no other RCD's in series all circuits are protected by the one RCD.Any thoughts? Going to RAMP test it etc tomorrow.

 

[Octopus]

Strange one here. I installed a garage installation about 6 months ago. few sockets and lights etc. fed from a sub board. Sub board is fed by 32 amp breaker on 30ma RCD side of board. Original board is a single RCD board. I did not touch the main board as the sub board and feed where already installed by another spark and were suffficient for the addtions.I have returned to same job but working on the attic now. There has been no problems at all with garage since I left. In the loft there was another sub board feeding again lights and sockets. However I needed to put in a new 4 way board in order to incorporate underfloor heating in attic en-suit. When I did the calcs the original MCB supplying the attic was too small and needed to be changed from a 32amp to 40 amp in order to protect additional underfloor heating circuit.When I changed MCB I noticed the down stairs sockets (which I hadn't worked on) started to trip RCD. Anyhow after abit of jiggling about in the board that stopped. I carried on with installation and as I powered up "TRIP AGAIN" I located the trip this time to the garage sockets when neutrals touched neutral bar tripping. In the end I took most the sockets apart and could't get any poor reading etc. When I put everything back tripping had stopped and everything was back to normal. I made a mental note in my head that I did not want to open that main board again as there is an intemitent fault on the RCD side.Got another call today RCD tripped in conservatory when the hoover was plugged in. I'm seriously thinking dodgy RCD that needs to be replaced. Or maybe splitting the load of other circuits across two RCD's in a dual RCD board. By the way there is no other RCD's in series all circuits are protected by the one RCD.Any thoughts? Going to RAMP test it etc tomorrow.

Could you edit this entry to make it easier to read?

 

[highspark]

Hope this helps

 

[Octopus]

Maybe Dan could limit the characters in a paragraph to stop these awful posts!

 

[tony mc]

I would be looking at what the leakage on the premises is.

A single RCD can trip out at anything over 15mA so its easy to tot that up and have the RCD tripping out when appliances are plugged in.

Ramping the RCD will only give you the figure that it trips out I would be clamping the tails for starters!

 

[GLENNSPARK]

it takes what.....a munite to perform a ramp test......so it would be better to do this initially if suspect.....rather than waiting to see if its cabling etc....could save you a lot of time searching for summat that aint there....