Post
by ericmark »
Sun Dec 12, 2021 11:07 am
I had the same with old RCD's fitted around 1992, the rapid change in load would trip the RCD, if I turned off all MCB's at the converted fuse box I could re-set the RCD and then one by one switch the MCB's back on.
In my case testing with an insulation tester (500 volt ohmmeter) and using a RCD tester showed no faults. Which is why when I moved used all RCBO's (RCD and MCB combined) so any trip is isolated to one circuit, but these were not available back in 1992.
There are three tools used to test, the clamp-on ammeter, the installation tester, and RCD tester all expensive so in real terms it is cheaper to call an electrician.
To just replace a RCD without testing is not really possible, I have found over the years strain exerted on the case of RCD by the cables can result in them failing to trip, or tripping too early, so RCD's need testing after being fitted to ensure they still work, and the tester is expensive so not a DIY job.
