ZE & PFC Relationship

[burntwire]

What is the relationship between ZE & PFC readings, sometimes they measure around the same amount and sometimes very different eg, ZE 0.13 and PFC 1.57
If the readings are further apart does this indicate anything, same as if they are similar readings does this indicate anything ?

 

[RF Lighting]

How are you getting the two readings?

Is it from your tester, or are you calculating Ipsc?

Ipsc is calculated using basic ohms law.

I=V/R

If the Ipsc reading is changing, but the Ze is the same, them the voltage must be different / fluctuating.

 

[burntwire]

Testing with meter, I prefer not to calculate

 

[RF Lighting]

Does it have a current calibration certificate?

 

[burntwire]

Yes within the last 2 weeks, Imust apologise my first post wasnt very clear, I do not mean the tests were carried out at the same property with fluctuation but at different properties altogether,

I was just wondering why they changed so much and if they should be similar figures as probably 90% of my results are very similar or the same

 

[RF Lighting]

They should be all near enough the same.

Average supply voltage tends to be between 236V and 245V

With a Ze of 0.13Ω, you could expect the Ipsc to vary between 1.82kA and 1.88kA

If you readings are differing wildly then I would start to suspect something like a dodgy set of test leads perhaps?

 

[sparkiedave]

The PFC readings should be taken with all bonding in place where the Ze should be taken without, so the readings will vary depending on parallel earth paths etc

 

[Spark123]

Also PFC can be phase to neutral or phase - phase fault current (PSCC) as well as phase to earth (PEFC), whichever is greater.