Electric Reference

Description of test

Performing this test is to ensure that there is continuity throughout the circuit, that there are no breakages and conductors have been connected correctly. Be sure you have isolated the supply before beginning the test.

 

Methods

            Test method 1 : Short lead Test

            Test method 2 : Long lead Test

 

Test Equipment

            Low Ohm Resistance Meter

 

Note: R1 = Resistance of Line conductor, R2 = Resistance of CPC, Rn = Resistance of Neutral

 

Test Method 1: Short Lead Test

A Typical example would be to cross connect the Line and Cpc conductors at the distribution board of the circuit going to be tested. At each point of the circuit, at test between Line & Cpc should be performed. Noting that as you perform the tests further away from the cross connected ends at the distribution board, the higher the reading will become. The result recording the highest reading will be the R1 + R2 value on the test sheets. Make sure the test leads have been nulled on the tester or subtracted from the results accordingly

 

Test Method 2: Long Lead Test

This test is slightly different to method 1, as you are only testing the Cpc. It is known as a long lead test because you may have to use an extra long cable to reach both ends of the Cpc. (Twin+earth can be used to create an extra long test lead). Making sure you null out the test leads before the test.

So basically what you have is your test meter connected to the Cpc at the distribution board and the other (extra long test lead, if necessary) test lead connected to the other end of the circuit. Perform the test, and record the highest result as the R2 value.