rcd test tripping both sides

[Liam12]

Had this on a rewire a year ago, later found one of the other sparks had wired the two way from the landing and hall wrong, 1mm's at bottom of the stairs with a feed and switch line, and a three core for the two way upstairs, the 1mm's for the hall light and the three core for landing light and switch fed it thinking it was a 1 gang switch not a 2 gang, could be a possibility

 

[electric8]

Thanks for all the help found the problem a screw had just nicked a cable causing a fault after i had done IR tests.

 

[Octopus]

Thanks for all the help found the problem a screw had just nicked a cable causing a fault after i had done IR tests.

Very odd conclusion. This should affect one side of the board not both!

 

[electric8]

Yes really baffling me but fixed problem redid all tests and everything now spot on .but having said that builders are stil on site and loosening fittings to decorate and tile behind and such, so may have been something else as well .but i am paid now and everything was perfect when i left it