Testing Zs of a circuit

[dingbat]

it will give you loop values which you can then use to CALCULATE the PSC, but a dedicated PSC tester ( or multi function tester with it on ) will give you the KA reading.

There is no such thing as a PSC tester! (Imagine the result of passing 1000s of amps through your equipment!) Loop testers use their measured impedance values to calculate and display an associated fault current.

A three-lead tester only requires the neutral to power the meter itself, the actual test is carried out between two leads only and, as you've suggested you need to put both the neutral and earth leads onto the neutral, which is harder than it sounds with some instruments. (Two-lead testers rule!)

So, you do a Ze test, record Ze and note the associated earth fault current, then put your two leads together and do a phase/neutral loop test and note the associated short-circuit current. You then record the highest of the two fault currents as your measured Pfc.

 

[didthathurt]

Imagine the result of passing 1000s of amps through your equipment!.

 

[ColJack]

I have a PSC setting on my multi function tester..
It reads in KA, and yes i realise that it just calculates it but that's what i was saying..

I never said it "tests" the fault current, that would blow the fuse or breaker anyway..

 

[dingbat]

Fair enough ColJack, but you did say 'dedicated PSC tester'.

Most loop testers do what yours does, though. Even my ancient Seaward SBS7671 does it!

 

[ColJack]

since I don't use seperate testers I didn't know..

I just assumed since you can get seperate loop, insulation resistance, earth electrode, rcd etc that you could get seperate psc testers too..