volt drop outbuilding supply

[Jackflash]

Hi,

Looking to supply power to two outbuilding/sheds to be used as offices (no electric heating required). one is 60m from supply source and another is 10m further on.

I'm currently debating what size supply / cable to install taking volt drop into account.

Ideally in unit 1 i'd have
-16a radial socket circuit
- 6a lighting circuit (1.3A Ib)
- 16a circuit to supply unit 2 sockets and fcu for lighting

Any ideas on what the best way would be to do this???? The volt drop gets a bit wild on a run this length.

To work out the total volt drop, would i first work out the volt drop on the swa run to the 1st unit (60m) using full design current for both units 26.3A then add the volt drop of the second leg (10m) using the Ib of the 2nd unit (12.6A) then add the volt drop for the furthest lighting point in unit 2. Then add them all together and make sure it's less than 3% 6.9v. Is this right?

Does my design current sound a bit high? each unit is having 3 sockets and 3 lights. Sockets are for basic office stationary and domestic appliences only.
I've calculated it using 90% of lighting (2.3A)
100% of 1st socket circuit (16A)
50% of 2nd socket circuit. (8A)
26.3A
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[HandySparks]

Why are you asking this again?

 

[pencilpusher]

Here's the original!

http://www.electriciansforums.net/e...trical-forum/73837-volt-drop-outbuilding.html

 

[Megavolt]

I'm having dejavu. You not like response you got from first go

 

[Knobhead]

My doctor gave me his 2[SUP]nd[/SUP] opinion this morning. “I told you last time, stop drinking!”

 

[fog]

Hi work out volt drop using OSG or if you lazy go to TLC electrical they have calculator so do it for first run/shed, to be honest if you do that correctly for both loads total load, you dont have to worry about volt drop on 2nd shed as there is no volt drop in 10metres, from first shed not long enough. dont get confused load is load . volt drop is volt drop. and yea is it future proof they say they dont want heating, could change later. Personnally i would upgrade SWA in for future proof so when they get you back to change ccu for larger one to accoma=odate heating circuits you will have power to do those circuits.

 

[Jackflash]

Thanks, so it's looking like either 20A mcb on 10mm swa or 32A mcb on a 16mm swa. This is taking into account a 3% volt drop for lighting. 16mm swa is a little bit serious so will have to work out actual power needed. There are log burners in each unit so heaters are not going to be used and i would state that in the estimate. If it's just card readers, till, computer, printer, phone, radio, 20A for both sheds could be ok.