Hi

[tochweens]

Hi please l did a testing on a TT system

Am having a reading of 200 ohms and my pfc is 1 amp @ loop high reading

With same 200 ohm
Pfc 1amp
Psc 2.67kva at a low reading
But am abit confused about the 1 amp pfc if its right
Its a new calibrated meter and its working perfectly

 

[westward10]

Your PFC should be the highest value between line/earth or neutral/earth. With TT it is always going to be the latter due to the high impedance between line/earth.
You are clearly using the line/earth impedance for your PFC and simple ohms law would give you around 1A (230÷200).

 

[tochweens]

Your PFC should be the highest value between line/earth or neutral/earth. With TT it is always going to be the latter due to the high impedance between line/earth.
You are clearly using the line/earth impedance for your PFC and simple ohms law would give you around 1A (230÷200).

Thanks for the response
That mean l can record PSC (2.6kva ) on my. report since

 

[westward10]

Thanks for the response
Does that mean l can record PSC (2.6kva ) on my. report

Is that line/neutral?

 

[DefyG]

The NICEIC EIC/certificates asks for 'Prospective fault current' Pfc not Psc although some certificates (Napit etc) may require Psc?

Entering Psc and not Pfc may lead to misinterpretation of the supply characteristics and a RCD may be omitted when in fact it will be required!

 

[tochweens]

Is that line/neutral?

Yea PSC (L-N) reading

 

[tochweens]

The NICEIC EIC/certificates asks for 'Prospective fault current' Pfc not Psc although some certificates (Napit etc) may require Psc?

Entering Psc and not Pfc may lead to misinterpretation of the supply characteristics and a RCD may be omitted when in fact it will be required!


View attachment 122600

A ....1 Amp fault current would be considered very low and likely not a problem for a TT system, as these systems rely on RCDs (Residual Current Devices) for fault protection, which are sensitive to much lower fault currents. Each DB has an incoming 61008 Rcd and Extra main old Rcd protection

 

[DefyG]

rely on RCDs (Residual Current Devices) for fault protection, which are sensitive to much lower fault currents.

yes Pfc!

BS61008 RCD's will not provide overload/short circuit protection - the Psc value!