Volt Drop

[Monkeyblaine]

Would I be correct in assuming that the supply cable which enters your house has been (in theory) calculated in such away as that there will be no volt drop across it as to ensure that 230v (or thereabouts) is at your DB and available for all your circuits, providing they have ample size conductors for their individual purposes. And would I also be right in saying that if you supplied a submain at the bottom of your garden which had a volt drop of 5volts along it, then every circuit being supplied from that submain wont be allowed the usual 3% allowance for power and 5% for lighting as it has already lost 5 volts through the submains supply cable... I know this is probably a silly thing to ask but I love being double sure...

 

[morph]

the VD is a total so yes if you have lost 5 % AT DB2 in shed then you should not have anymore VD at the end of those circuits in the shed

 

[telectrix]

try telling that to one of my regular clients who is lucky to get 210V at the service head!

 

[morph]

should be + / - 6 % roughly ( cant remember the exact % , so could ring the DNO on that one 210 v is a tad low

 

[telectrix]

ROFL. phoned DNO. they said " tough, that's because it's a long run from the sub-station, nothing we can do. ". they quite happily quoted £20k for a 3 phase supply though.

 

[sedgy34]

try telling that to one of my regular clients who is lucky to get 210V at the service head!

compulsary voltage optimisation i like it!!!:rockon:

 

[Knobhead]

Just shows what a load of B*** S*** the maximum volt drop requirements of BS7671 are. You carefully calculate the voltage at the end of a lighting radial and what happens? Mrs. Jones turns the kettle on next-door and the lights dip in your house.

My last flat in the centre of Nottingham the lights would get dimmer and dimmer when I returned home off nights. It was as the city centre hotels fired up the kitchens for breakfast. At about 6-45 the 33/11KV On Load Tap Changers would kick in and the voltage would shoot back up. 7-15 the same would happen again. I put a recorder on the incomer, the voltage looked like a saw tooth waveform. Between 6-00 and 9-30 the voltage would change 6 / 7 times. DNO’s response “nothing we can do about it”. They can’t control 40MW, what chance do you have with a 60W lamp?

If anyone knows Nottingham, I was supplied from the primary sub at the side of the Britannia Hotel.