fault finding.....

[webby_58]

hi everyone newbie here...

i have recently passed my part 2 technical course & 17th edition and want to move into domestic electrical services. i have done a few small jobs for people gaining more experience as i go.

am waiting to do my test and inspect 2392 course, but have been asked to look at a light for someone that keeps trippng his fuse box - not sure if mcb or rcd as yet. i do have a 17th edition multifunction tester, could someone advise me of the correct series of tests to do to find the fault if not as simple as a loose connection. thanks in advance... IW​

 

[telectrix]

first, a visual inspection of light fitting and switch, with power isolated. most of these faults are down to shorts, trapped conductors etc. at terminations. next check to see if a nail or screw has been put through cable above switch. if nothing obvious, use your tester on insulation resistance ( IR ). disconnect all 3 conductors in CU and measure L/E and N/E with switch on and off. ( anything under 2 meg is suspect, and will cause RCD trip). if it,s MCB tripping, then a short between L/N could be the culprit.

 

[webby_58]

thank you, looking at it on saturday will let you know
cheers