3Phase PFC

Zdb · Oct 11, 2019

After having a discussion with a colleague earlier today I was wondering what peoples preferred method is when testing prospective fault current on a three phase distribution board.

Do you:

A. Perform a 2 lead test between L1-E, L2-E, L3-E, L1-N, L2-N & L3-N then double the highest value.

Or

B. Perform a 2 lead test between L1-L2, L1-L3 & L2-L3 then record the highest value without the need to double?

farmerspark · Oct 11, 2019

When measuring PSSC I measure between line and neutral and double as works tester can't do line to line. PEFC is always the highest of line to earth

SparkyAndGeorge · Oct 11, 2019

I prefer option B. However if tester cannot perform this function, option A but you do not double, you multiply by 1.73 (square root of 3)

Strima · Oct 11, 2019

I tend to do a line to neutral just to confirm the neutral is working. Then phase to phase to test between all three phases. Finally all phases to earth.

Zdb · Oct 14, 2019

Just had a look through GN3 and apparently the most accurate way is to test between line - line and then divide the highest value by 0.87. I'm sure I wasn't told this on the 2391.