hello chaps, i know we calculate vd at a nominal voltage of 230v but as we all know our real voltage in the sockets is about 245v does thi mean i can go down to 218.5v (5% of 230v on power)ie drop approx 26.5v or 5% of measured voltage
many thanks in antisipation

Not always - my supply at home is only 220V most of the time, where I am at work at the moment it is 232.9V, but can be as low as 230V and as high as 240V, depending on the day of the week and time of day.

I would not really be tempted to calculate volt drop during design on the basis of a higher nominal voltage - it could vary significantly at times other than the time of measurement due to loading of the distribution netwoek on and could be changed by the DNO by reconfiguration of their distribution network, the changing of transformer taps or indeed the replacing the distribution transformer.

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Ross Currie TMIET