Online assistance for electrical trade people in New Zealand and Australia Login  |  Register  |   Forgot Password
Assistance for electrical trade people
 

 

 

 


Click here to send Ron a pdf document for publication on this Topic

Documents must be less than 200k in pdf format

Posted By Topic: Earth test

Tommy
Mar 24 2019 15:38

Hi I have always tested metal lights by running an independent earth wire temporarily from a roll to a long screw driver driven in ground is this correct a sparkly friend says you can run the independent testing lead from the earth bar to check earth continuity
Is either correct
Thanks
   

DougP
Mar 24 2019 16:58

Independent earth to the screwdriver is for testing polarity.

For an earth continuity test, connect your trailing lead to the earth bar. Section 8 or 3017 had the details.
   

Tommy
Mar 24 2019 20:23

Thanks dougp much appreciated 10 years ago when I was apprentice no tradesmen did any tests think I have got it Sussed now would be good if there were simple test procedures to learn
   

Someone
Mar 24 2019 21:53

Not just polarity testing, but you are specifically testing the polarity of the incoming mains.

I agree that testing is poorly taught, and in my experience consists of people saying 'this is my favourite way to do it' without explaining why or what it achieves...
   

MitchB
Mar 25 2019 09:18

A lot of multifunction testers also tell you the EC when you do EFLI tests, which helps to kill two birds with one stone.
   

benben
Mar 25 2019 12:01

Mitchb, yes they do but you dont EFLI test every light.

Tommy, go to earth bar, sometimes u go to the closet power point and use that earth( has to have past testing tho)

Also been in the game about similar time and back in those day the only testing done was when something went bang. Karapiro test they called it i think. Problem is i have had to teach my self how to test, as ZERO testing was done back then. the old she'll be right.


   

MitchB
Mar 25 2019 14:54

benben, if your EFLI test passes, your EC by default is ok. If you want to test the individual fittings, I guess you could also go between them with an ohmeter off a ladder to ensure they're of equipotential, and then EC by way of EFLI at the furthest light on the circuit.
   

AlecK
Mar 26 2019 10:35

"if your EFLI test passes, your EC by default is ok"

Not necessarily true. Even for the smaller sizes where PEC is same size as active.

It's a generally reasonable assumption; but can't be relied on; as a combination of very low impedance active and excessive impedance PEC can add up to a "compliant" EFLI.
So earth continuity should be measured individually for every point required to be earthed; then in addition EFLI should be measured for non-RCD sockets
   

Someone
Mar 27 2019 18:45

Comparing phase-neutral and phase-earth values mostly guards against that, though.

The main issue is checking for earth-neutral transpositions, at least in non-residential where RCDs aren't fitted.
   

AlecK
Mar 29 2019 09:55

True we are alowed to use alternative test metyhods; but they have to be no less reliable than the ones in "3017".
"mostly guards against that" doesn't meet that criterion.