Can an electric shower break an RCD unit?
A shower would not ‘break’ and RCD. Testing of the RCD using proper test equipment would show if the RCD was working and tripping properly. This should have been the first thing the engineer should have done. Ask both the parties who should have tested the RCD’s BEFORE replacing them, for the test results. If they did not test them, or if the values post-test were acceptable, then you should not be liable for them taking a wild stab in the dark and changing the RCD. When I say ‘test’ I do not mean pressing the button to see if it trips. Ask for the half-delta-N value, the 1-delta-N value, and the 5-Delta-N value, on both sides of the wave-form. If they cannot provide, don’t pay. If they can provide, you will need to get another electrician to verify that the values for the current RCD matches the readings given. If it’s not the shower, and the RCD has been changed, it sounds like it’s the cable to me. Connections should be checked by a qualified person, and an insulation resistance tes
