Alternative zs testing

[soulman]

Hi, Can someone point me to Sinatra's explanation of fast loop testing with rcd's. Measuring zs at the board & linking out at the extremity of the circuit

Cheers

 

[Richard Burns]

I am not sure where that post is located now but the procedure is straightforward.
Alternative Zs Test:
Safely isolate the installation.
Have main switch off, all MCBs off and all RCDs off.
Link line and cpc at the furthest point on circuit.
Use a two lead high current earth fault loop impedance tester.
One probe goes on the outgoing side of the MCB of the circuit that you have linked out (and so is connected to earth via the line).
The other probe goes on the incoming line conductor of the main switch, which will be live.
Measure the Zs and record.
You can also switch on the MCB and then place your probe on the outgoing line of the RCD, this will include the MCB in the test.

 

[polo1]

Richard, what software are you using to produce your diagram?

 

[Richard Burns]

Richard, what software are you using to produce your diagram?

I am just using powerpoint on here because it is easy to edit lines and save to jpg.

 

[Marvo]

Visio is also handy for quick sketches and you might be lucky and have it bundled with your Microsoft Office disk if you've got one of the higher end Office versions like Pro or Premium