pfc calculations

[wire the world]

hi guys doing calculations ov pfc at the consumer unit i have a ze=0.09 getting the figure ov 24ka doin 230/2400=0.09 is this correct many thanks

 

[calv68]

is that not 2.4ka

 

[slocm3105]

it is indeed 2.4ka. By applying the calculation that you did gives you the answer in amps. However I think you meant to write 230/0.09 = 2400. Therefore 2400 amps is 2.4kA.

Hope this helps .

 

[wire the world]

cheers nulled tester and got ze =0.07 so within regs for a tn-s

 

[ian.settle1]

cheers nulled tester and got ze =0.07 so within regs for a tn-s

so was the first reading you quoted 0.09

 

[slocm3105]

cheers nulled tester and got ze =0.07 so within regs for a tn-s

Yes the first reading you got of 0.09 was also fine. As TN-S Ze is ok up to 0.8 ohms, not 0.08 ohms.

Cheers

 

[wire the world]

yes i tested ze and got 0.09 then tested again and got 0.07 do you see aproblem i???????

 

[ian.settle1]

yes i tested ze and got 0.09 then tested again and got 0.07 do you see aproblem i???????

Only 0.02 ohms eg 200 hundredths of a ohm which is negligible.

 

[wire the world]

thanks for the reply.... got ze =0.07 so 230/0.07= 3285.000000 so the pfc ov the tn-s system is 3.2 ka??????????? are my calcs ok?????????? im not sure what the max is on tn-s system thanks

 

[Amp David]

Correct, but i'd always round it up to 3.3ka.
TN-S Ze max is 0.8 as already stated in another post.

 

[Spazz]

I know this is an old thread but thought I would post on this instead of starting up a new thread

Got a Ze reading of 34.97ohms on a TT system - forgot to look at PFC

230/34.97 = 6.577 so 0.006kA - is that right??

 

[dagrat]

Yes that's right 230/34.97=6.57A. = .0065KA
But it's essential to carry out the test anyway

 

[Deleted member 26818]

What you have there is a value for PEFC, not PFC.
I'd call it 0.007kA rather than 0.006kA.

 

[HandySparks]

I know this is an old thread but thought I would post on this instead of starting up a new thread

Why have you posted this twice?

 

[tony mc]

Is this for recording on your certificate ?

This value would be classed as your Ra!