Pfc reading

[ala]

Hi,
I have recently tested a new installation i have completed on a domestic property. All the relevant tests were completed and verified as ok. However the PFC reading was > 10ka.
My Fluke test instruments only give a greater than value if 10ka is exceeded, so I do not have the actual reading.
The system is a TNCS
with readings of:
Ze: 0.11
even measured the Voltage just to be on the safe side:
V : 245

Obviously the calculation using these two measurements would suggest that the pfc is below the breaking capacity of my mcb's as it would be around 2.2ka.

Can anyone shed any light on this, or suggest any methods on how to acheive a lower reading (other than moving the house further from the source) ?????

Cheers
Alan.

 

[Phil Mumford]

I would suggest that you meter is on the wrong setting or needs calibrating/repair.

I took some readings earlier today: Zs 0.16 Pfc 1.29 kA. This is fairly standard for a domestic.

You would need to be right on top of the sub with huge incoming cables to achieve >10kA. Only happens in factories etc in my experience. Anyway - if you ring the NICEIC they will say that the breaking capacity of the HRC fuse (BS1361) will protect the entire installation - that is why we can let rewireable fuse boards off the hook when performing a periodic.

Hope that helps.