Voltage drop taken to extremes

[TaffyDuck]

Just been asked to go and check out a new agricultural barn wired up by a builder. The barn is 350m from the house ( where they have fed it from a socket in the living room) and they have fed it with 1.5mm two core SWA." because its only a socket and a couple of lights".

 

[telectrix]

no problem. fit a 110 socket and step up transformer. and some 110v site lights on a string.

 

[telectrix]

top of me 'ed without looking up 13A would just about give a VD of 110V, so ideal for the odd 110V power tools.

 

[Mark_Burgess]

Did you measure the VD, I'd like to know how accurate the book figure is to the real thing.

 

[telectrix]

the book gives a VD of 130v at 13A, so i was close. like to know a real life figure. of course he could always DUCK out of this one

 

[TaffyDuck]

Well i only had my little fluke T100 on me, so no accurate reading, well below 200V though and I wasnt going to trudge quarter of a mile back down a hillside to get the megger but tel is about right. will get a proper reading at the end of the week but I make it, on paper a VD of 140V!!!!!!

0.031 x 13 x 350

 

[telectrix]

looks like 25mm will be needed as minimum. that will give around 6V VD at 10A.

 

[TaffyDuck]

I guessed at that onsite, 25mm 3 core x 350m = BIG MONEY and the will have to bury it again lol

 

[telectrix]

be cheaper to use a genny.

 

[TaffyDuck]

absolutely right, either way not my problem thank god. Whats 3c 25mm SWA at the moment £5 a meter at least I would think. Thats £1750.....ouch

 

[Dunc]

Just for giggles I'd like to see someone try making that off in to the back of a FCU!

 

[TaffyDuck]

Just for giggles I'd like to see someone try making that off in to the back of a FCU!

lol, very true. Havent even added a bit for 3 x armoured resin joints, they will add a fair bit of VD to the system

 

[JD6400]

I guessed at that onsite, 25mm 3 core x 350m = BIG MONEY and the will have to bury it again lol

Now that connection in the back of the living room socket will be worth a photo !

(I must improve the speed of my typing , been beaten to it yet again !)

 

[SPARTYKUS]

Can you get 200mm DG surface patressses

 

[HandySparks]

Still, you could always leave the existing cable in as an independent lighting supply. You can fit up to 145W and stay within the 3% VD!

Edit: You might have to put it on a 3A breaker to meet the Zs though.