ban-all-sheds wrote:
"The worst case voltage drop in a ring is equivalent to the drop of a run of 2.5mm2 cable ¼ the total length of the ring."
Is the voltage drop in the cable length of a ring circuit not calculated in the same way as in the single cable length of a radial circuit? When I add the total length of a cable in a ring it either turns out to be too long in my calculations, or the circuit will only support around 10amps, and always the drop is close to the 9volts too; and this is not allowing for other cable-derating factors either.
Could the actual voltage drop in a ring be ascertained (if tested by an Electricity Board eg) by applying the current rating of the protective device in that circuit (the fuse/breaker rating), rather than applying some assumed design current? Satisfying fuse rating would be the worst case scenario anyway wouldn't it?
"The worst case voltage drop in a ring is equivalent to the drop of a run of 2.5mm2 cable ¼ the total length of the ring."
Is the voltage drop in the cable length of a ring circuit not calculated in the same way as in the single cable length of a radial circuit? When I add the total length of a cable in a ring it either turns out to be too long in my calculations, or the circuit will only support around 10amps, and always the drop is close to the 9volts too; and this is not allowing for other cable-derating factors either.
Could the actual voltage drop in a ring be ascertained (if tested by an Electricity Board eg) by applying the current rating of the protective device in that circuit (the fuse/breaker rating), rather than applying some assumed design current? Satisfying fuse rating would be the worst case scenario anyway wouldn't it?