Pfc and Ze - values by enquiry? (UK)
Pfc and Ze - values by enquiry? (UK)
(OP)
Hi folks,
When installing a new board in a domestic situation, you have the option of aquiring the Prospective fualt current, and earth loop impedance values by enquiry. Who do you contact to for these details?
When installing a new board in a domestic situation, you have the option of aquiring the Prospective fualt current, and earth loop impedance values by enquiry. Who do you contact to for these details?






RE: Pfc and Ze - values by enquiry? (UK)
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I'm getting a great education!
RE: Pfc and Ze - values by enquiry? (UK)
as scotty says, if you ask the LEB they will give you figures that are high and often by quite a lot. We recently asked for some figures and were told 16kA (P-P), when we measured it it was only 4kA (P-E so maybe 8kA P-P)
RE: Pfc and Ze - values by enquiry? (UK)
RE: Pfc and Ze - values by enquiry? (UK)
The REC always used to quote you 16KA (@ 0.55pf) as a maximum potential, this was assuming you were located next to thier transformer, as you found when you move away from the source and measured the reading it is significantly lower. Their figure is a distance of 35M for 4KA.
There are standard figures accepted and quoted for use typically 0.35 ohm for a TNCS - PME system, and 0.8 ohms for a TNS system as I recall. These can be used on your paperwork as the REC will quote these if you enquire. There is no substitute for a real test though.
Regards