voltage on earth terminal
Posted: Tue Nov 02, 2010 8:27 pm
by ian2799
just fitted some lights via klik box in a industrial unit problem came when i went to do some testing i found when i disconnected the earth wire from the klik box i had a potential of 120volts between the earth terminal and the steel trunking when i removed neutral this voltage rose to 240 volts is there a possibility that the neutral connection has been lost closer to the origin would appreciate any help
Posted: Wed Nov 03, 2010 9:14 am
by ericmark
Cables have capacitance and inductance and without knowing the currents involved the readings mean nothing.
Inspecting and testing is a specialist subject and if not done correctly can be dangerous and it also requires special meters to measure high ohms with 500v and low ohms with 200ma plus earth loop impedance, prospective short circuit, and RCD tripping currents and times.
Look for the C&G 2391 or C&G 2392 for qualifications required and remember insurers will need proof of the qualifications before you get professional indemnity insurance. Because it is an option not work done public liability insurance often will not cover.