ze reading on a job

[sparkysam]

Hi there all, had a job today, installing a new circuit, done a ze at board and got 0.02 with 10kA for pfc, board was a hager with 6 ka rated mcb"s, done it again and got 0.07 with 3.5kA if I remember rightly, I know reading may diiffer slightly but isn't that a bit much, I'm using a fluke 1653b, only a year old. Supply was pyro so was expecting a low ze , would I take the lower or higher reading??,

 

[NozSpark]

When you take readings you always record the worst case ones.

So for Ze it would be 0.7ohms if it's a repeatable results

and for PFC it would be 10kA,,, again, assuming repeatable results

If your results are not repeatable then you need to check your meters batteries and leads, also check for loose or poor connections where you are testing

 

[SLIPSHOD & SLAPDASH]

I personally would have tried another couple of times to confirm, could have been poor contact on the first test .

 

[sparkytim]

If this C unit is supplied via a 1361 type 2 supply fuse then it will have back up protection of 16 kA so your 6KA MCBs are fine.

 

[sparkysam]

Wouldn't the mcb"s blow up first before the main fuse blows?

 

[sparkytim]

No