Portable earth test

[John2016]

Hi all - new here - with a question that's been bugging me for a long time - I'd like to build some (maybe from existing kit) that would test for earth continuity - but I want it to be hand help - and no second probe - I.e. If I had a room with 100 computers all plugged in - I'd like a probe/pen that I could very quickly walk around and just touch on a bare metal part , and then some indication that it has an earth - maybe by plugging something in to a spare docket as a transmitter - I have tried a telephone tone generator - it doesn't work for some reason through an earth ring main - hope everybody understands what I'm after ?

 

[Minder]

IF you simply want to see if earth leakage is present one of the Electricians neon screwdrivers will light at the slightest leakage.
I once had one light off a newly laid brick wall where a cable feeding an outside light had been penetrated by a mounting screw.
But if a computer has an earth leakage and it has a valid earth ground conductor it won't indicate. But if it has leakage and is not grounded, it will.
M.

 

[Alec_t]

Welcome to EP!
Unfortunately, just having earth continuity isn't enough. The earth connection has to be capable of passing fault current and needs to be low resistance so that the current doesn't cause the equipment potential to rise to a dangerous level. The earth test therefore needs to be comprehensive and carried out using high current, to ensure the connection complies with wiring Regulations. I don't think a single hand-held probe will do the job.

 

[Minder]

When I started out as an Electrician in the UK we all carried one of the screwdriver testers mentioned, for further test we used a low resistance earth test Megger.
M.

 

[Bluejets]

High current is not required but appropriate sizing for circuit conductors and length of run are along with the correct low reading to match the type of circuit breaker in use. Also it is a requirement that neutral conductor is disconnected during test in an MEN system. Obviously without any power ..... Have thought about easier way to test other than drag a trailing lead all over the site but alas the old tried and proven method simply cannot be replaced.