Calculations

[Spikenaylor]

Hi there.

getting all confused over calcs.

Need to power two PIR sensors on poles run from TT distribution board L1 phase own little circuit for the small building the panels are kept in on small caravan site.

SWA from MCb through DP switch out to 1st light then onto 2 nd light.

Load current = 1000W/230V = 4.35A

6A MCB

1.5mm SWA 4 core using core as earth and spare core as future switch wire (maybe or maybe not - at least it is in place) rating 18A table 4D4A

not checked ZE yet, but assume 10 Ohms (it is TT installation)

theroritical R1+R2 = 24.2mOhms *1.2 = 29.04mOhms/M 31M = 0.9 Ohms

ZS = 10.9 Ohms

to high for 6A breaker, but RCD fitted

Theres not much else I can do is there, the ze is the main culprit.

any advice or point out my mistakes.

 

[Worldz]

The extra core used as earth as well ? To try and lower that zs

 

[telectrix]

make very little difference with that Ze value.