Check of Earth in Home Ask questions and find answers to many subjects relating to electrics and electrical work

[estwest]

Hi

I have 2 young children and am concerned about the continuity of electrical earth through our house. No particular reason other than we bought the property a couple of years ago and although much of the wiring is recent it has not been comprehensively rewired.

I was thinking of checking the resistance between the earthed item and earth or the neutral (having turned the power off first) using a meter - can someone advise on the best way of doing this. Many thanks

[sparx]

Hi there ,
what you propose is a good idea in principle, however a couple of points to consider;
If you correctly turn off main switch to do continuity tests then you have disconected your Neutral from it's link with Terra Firma, so you must go from earth at board to various points.
If you do the tests using a common inexpensive multi meter your results may be less than reliable with regards to actual effective earthing under fault conditions because the high input impedance of digital meters put no current load on circuit, this is why regs call for continuity testers to draw 200mA through circuits under test.
When we do bond tests during Completion/Periodic Inspection tests I use either 4.5A or 25A bond test depending on which tester i am using, neither are cheap bits of kit, £235-£780+ , which is part of the reason qualified electricians have to charge quite a bit to do an inspection,
very pleased you are thinking safety, wish more people did!
regards SPARX

[estwest]

Thanks for the advice, so what I understand is to check the effectiveness (and be certain) I need to get an electrician in.

The multimeter route will tell me if there is an earth (ie it has not been disrupted) but not how effective it would be in a fault condition and as my earth source I need to go to the board and not use the neutral.

What is the sort of ball park quote I should expect for the inspection?

regards

[sparx]

Hi, only way to get a proper inspection / test is to request a 'Periodic Inspection' report from some one registered with NAPIT/ECA, who will then do all reqd tests with results on paper, this should cover all circuits ,
as for cost it varies; Area, number of circuits etc, could be from £120-£200, regards SPARX