Testing / Supplementary bonding

[Djjeff99]

Hi
I have read this thread = http://www.diynot.com/wiki/electrics:speclcn:supbond17th

It says that sup bonding may be omitted if 3 things are met , the 3rd been if = ■All extraneous conductive parts in the location are effectively connected to the protective equipotential bonding.


Can anyone tell me how to physically carry out the required test please ?

 

[ColJack]

low ohm meter and a long lead..
zero out the long lead and measure from the main earth to any metalwork..
check the reading is low enough..

 

[Djjeff99]

Cheers

 

[Taylortwocities]

And what would be the maximum figure that you would accept for this test, Djjeff99?

 

[ColJack]

says 1666ohms for a 30mA rcd..

but that's surely the Zs, so the resistance of the live would need to be included in that as well as the Ze?

 

[Taylortwocities]

He will be testing that

"All extraneous conductive parts in the location are effectively connected to the protective equipotential bonding"


That is completely different to Zs

Useful article that explains all here http://www.theiet.org/publishing/wiring-regulations/mag/2008/27-bonding.cfm?type=pdf

 

[holmslaw]

..

 

[Taylortwocities]

you will get an acceptable reading (<0.5ohm) .

Its time you got some up to date information shipped out to jungle land.
Or stop posting incorrect information on a DIY forum..

Guidance Note 3, states that the resistance of supplementary
equipotential bonding conductors should be no more than 0.05 &#937;

Not half an ohm.

 

[Djjeff99]

I belive the test you are discussing above is a test to confirm a bonding connection between extraneous conductive parts , where required .

My original question was how to test that
&#9632;All extraneous conductive parts in the location are effectively connected to the protective equipotential bonding.

Which was answered in the 2nd post by using a wander lead from the MET and checking that the resistance at each part does not exceed 1666 ohms .

Am i right in thinking the test you are discussing would only be used if there are circuits within the location which are not RCD protected i.e. installed under the 16th edition which would mean supplementary bonding is still required.

 

[davelx]

I belive the test you are discussing above is a test to confirm a bonding connection between extraneous conductive parts , where required .

My original question was how to test that
&#9632;All extraneous conductive parts in the location are effectively connected to the protective equipotential bonding.

Which was answered in the 2nd post by using a wander lead from the MET and checking that the resistance at each part does not exceed 1666 ohms .

NO! THINK about it. A direct fault from live to metalwork connected to the MET at 1666 ohms will pass a current of only 138mA - the CPD will NOT operate and the metalwork will remain at 230V ready to kill whoever touches it. The 1666 Ohm value is only applicable when there IS an RCD.