pfc results

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buddha

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hi , my newly calibrated meter seems to work fine but I seem to be getting really high results for pfc,quite often well over 6ka,Ze readings rarely over 0.03 ohms, most of these tests are on boards in high rise flats,would all the earths from each flat cause a really low ze reading and high pfc results? should I really be changing every breaker to 10ka breaking capacity breakers?? has anyone had the same observations? my meter is a megger multifunctional tester,about 7 years old now.

 
Does it need to be zeroed?

if so how have you done this?

is your PFC calculated by the meter directly from the Ze, i.e. A dual,reading. As an un zeroed Ze will,give a moody reading and even moodier PFC

my Fluke has to be zeroed and comes with a funky metal,shorting adapter . I do not know f this applies to all meters

 
This is an oddly named thread. The PFC results are correct for the Ze readings you have (Ohm's Law). Low Ze in Flats might occur for a number of reasons, could be a Tx in the basement and 3 core SWA, 3rd core and armour as Earthing conductor would lower Ze.

I recently found my funky fluke zeroing adaptor, used an earth block in the interim.

 
I cannot see the problem: 230 / 0.03 is???

So the place has a low Ze and a high PEFC. Oh well, as has been pointed out this is perfectly normal. I went to a house the other day and they had an 11kV TP supply to a pole actually in their garden and a rather large TX to supply the whole village on the pole just about 30 feet from their cutout. Bet their PFC and PEFC were just a little high!!

When Tony mentioned "front end protection" there was a very good and valid reason for that..

john..

 
People should also look at let through energy. 

Just because you have a PFC of XX KA, does not mean that if there is a fault that is what will flow. This is to do with upstream protection. 

 
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