Volt drop

[Farmelectrics]

Ok you do all your calculations to determine your volt drop and your calcs come back that the volt drop is just above the 5% allowed ok I no it dosnt conform to bs7671 and you should increase the csa of the cable to next size up but what effect or could some one explain in simple terms the problem we could face if we didn't

 

[plugsandsparks]

Most obvious is that some fluorescents wont fire up or keep dropping out.
TBH i often look at the supply voltage as well cos i keep coming across quite high voltages often in excess of 240, so a bit of drop is sometimes welcome.
Not BS7671, i know, but how the DNo get away with supplying 253V makes 5% somewhat irrelevant.
If your supply is already at the lower end e.g. 220 then you really dont want to drop anymore as lighting will be less effective, heating will take longer to work, but at least electronic equipemnt should be OK.
Dont forget its also based on how much current you will pull in your calcs

 

[Knobhead]

-5% of +10% or -10% of 230V @ 2A or maybe 7.5A or it could be 6.584753A ? ? ? ?
What was the question ? ? ? ?

My brain hurts ! ! ! !

 

[Farmelectrics]

Keep it simple tony lol

 

[Welchyboy]

You can't really make any assumptions on the DNO voltage as this will fluctuate dependent on the load as well as your circuits

 

[kingeri]

I do voltage drop calcs at the nominal voltage of 230v. You can measure the DNO's voltage one day and find it to be different the next day! It's hardly a major issue in most cases, unless you have very long cable runs and/or huge loads.