D
Dazzol2009
A friend of mine wanted to upgrade his lighting circuit in his three bedroom house, his house is fairly old, so his lighting circuit was only two core twin and earth (without the earth).
I rewired the complete circuit for him and commenced the testing, the R1 + R2 reading from the furthest point is 1.55 ohms, there are 15 points on the circuit plus the switch drops, they steadily range from the first point which is 0.15 ohms.
The external loop impeadance is a very low at 0.07 ohms, it is a TN-C-S , he does live one street away from a transformer unit.
When I tested the Zs at the furthest point, it came up with 1.15 ohms, my confusion now is the fact that the total Zs is less than R1 + R2 without even taking Ze into account, obviously I have haven't taken cable temps into account either, but it seems a big difference so I think this can be done later, any help in getting my head round this it would be appreciated.
I rewired the complete circuit for him and commenced the testing, the R1 + R2 reading from the furthest point is 1.55 ohms, there are 15 points on the circuit plus the switch drops, they steadily range from the first point which is 0.15 ohms.
The external loop impeadance is a very low at 0.07 ohms, it is a TN-C-S , he does live one street away from a transformer unit.
When I tested the Zs at the furthest point, it came up with 1.15 ohms, my confusion now is the fact that the total Zs is less than R1 + R2 without even taking Ze into account, obviously I have haven't taken cable temps into account either, but it seems a big difference so I think this can be done later, any help in getting my head round this it would be appreciated.
