high pfc

[Buzz-light-bulb]

Hi all

Just a quick one nothing too technical I hope, I've done a quick Ze and pfc test at a consumer unit (origin) and the results are 0.04 ohms and 8.1ka, the main fuse is a 1361 type 2 80 amp 33ka. But the Mcb's are only rated at 6ka, am I correct in saying that aslong as the ka value at end of each circuit is less than mcb 6ka all is ok, and that aslong as the ka at origin is not greater than 33ka all is is more ok

 

[polo1]

Are you sure of the 0.04 ohms reading or were you taking the reading at a transformer! Most mfts won't give accurate readings at that resolution.
Even at 0.1 you would be ok

 

[driverman]

PFC reading can not be higher than the max braking capacity of any overcurrent devices. Could the reading be in amps and not Ka. bit of ohms law possibly.

 

[topquark]

Do the maths on your Ze reading .... 0.04 Ze would give you 5750 A. So there's already something wrong! Hope you're doing the Ze on high current and not no trip.

 

[Chr!s]

Do the maths on your Ze reading .... 0.04 Ze would give you 5750 KA. So there's already something wrong! Hope you're doing the Ze on high current and not no trip.

I think the 8.1kA is the L-N

you should be okay provided the cu is type tested.

If its not you will probably still be okay.

Chris

 

[davesparks]

PFC reading can not be higher than the max braking capacity of any overcurrent devices. Could the reading be in amps and not Ka. bit of ohms law possibly.

Yes it can, as long as there is an upstream device capable of clearing the fault.

 

[GLENNSPARK]

i was at a place once with an old Wylex board with 3036s in it....PFC was about 9KA at the board...

didn`t like it....

 

[topquark]

Chicken!