25mm (SWA) Sub Main To My Shed?

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Connor Cox

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Hello so I've been talking with my mate, he's currently in college studying electrics. I've just rebuilt my shed for my server racks that I'll be putting in there. Now because I pull alot of power with my equipment + aircon I need at least 80amps possibly even 100amps for (future proof) (18-24Kw) I estimate it's 15 to 25m away from the house with all the bends etc. Haven't got a tape messure long enough  :Applaud Would the voltage drop be to high for 25mm at 25M plus the circuits included? Somebody suggested getting a new supply from Western Power but we all know how expensive that'll be as the nearest pole is out by the main road. So that's a no no. What's your thoughts?

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Are you saying you are going to pull 100amps in a shed  ???     :eek:         Your house  is probably fused at 80A   , the maximum demand probably  50A   .  That is SOME powerful computing power , no wonder you need Air con.  What are you ...a subsidary of NASA ??

If those figures are correct then you need a new supply at around £1800.00  at a guess  plus duct work on your land  etc .

Has a decimal point been moved  in your calcs ? 

A hint;     If your tape measure isn't long enough  you could try  measuring in multiples of it's length  and adding them together. 

 
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Yeah peak load mind, It's a hobby of mine expensive at that! SSE said we're on near enough a industrial usage, It's fused at 100amps, I currently have 2 racks they but intend to get more down the line and fill them up. While currently I'm not drawing 18kw more like 4-6Kw. What's the biggest sub main I could get to the shed without a new supply? Maybe 50amps?

 
sounds like you need a small industrial unit  :^O

4-6 kW is fine. Start taking 18kW off the house and you will have no capacity left for the house itself.

Daft question but is there anyway you can make some money from your hobby to pay for what you need?

 
sounds like you need a small industrial unit  :^O

4-6 kW is fine. Start taking 18kW off the house and you will have no capacity left for the house itself.

Daft question but is there anyway you can make some money from your hobby to pay for what you need?
I could if I had £4000 a month for a leased line @10Gbps :slap if I can get at least 10Kw to the shed then I'm happy, I do have a few older servers in the racks as well though so maybe swapping them out for newer ones will improve the efficency

 
I would love to see what i in these racks that draws 4Kw, let alone what you plan to add that takes it up to 18Kw

The submain on 25mm would probably be okay but there will be nothing left for the house to run on.

How about putting all this gear in the house? At least you won't need the heating on. Seems daft to over heat a shed then use more electricity just to pump all that heat outside.

 
Hi Connor,

First off, as has been stated, WPD will do you a new supply for about £1800. You could have a three phase one if you wanted. Do not run away with the idea that you could have any amount of power you wanted, it depends on network capacity in the area.

Having said that, if you can afford the electricity bill that 100A will give you, the cost of the new supply will not bother you in the slightest!!

Anyway, there is a lot more to cable sizing than volt drop.. Get yourself a copy of BS7671, have a good read, and you will know all you need.. [Hopefully]

Yes, we could work it out for you, BUT, there is a hell of a lot more we would need to know..

How were you planning to connect this cable up at the house end??

john..

 
One rack currently houses the servers and the other houses the network side of things both 42U APC racks, currently we fluctuate between 200-400 a month for electric, I would love to put them inside but being in a terraced cottage the neigbours complained about the slight noise/vibration or whatever, so I moved them to a small shed temporily while I do the other shed up. I'm only going by the smart meter (obviously we use other appliaces but yea

From what my mate said we could take 25mm from the henely blocks after the meter - That's the network side of things old photo

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Just being curious but what on earth are you doing with that much computing power as just a hobby?

You say line rental is £4K but how much would you actually make using it as a business. 24kW of servers is a lot! 

Another point to make, how secure is this shed? As in, you've a lot of expensive kit in there. 

 
It started of just one server on top of a tumble dyer believe it or not :slap and yes 4K is way to much at the moment so we're stuck on FTTP 330 - 30 mbps, the current shed isn't that secure hence why I'm trying to sort everthing out with the other shed as it has no electric. I currently run a web forum, a few game servers and a load of linux VMs, plus network storage. It's pretty annoying having all this knowledge within computers yet can't get a job doing it as I self taught everthing I know. Luckily the area I'm in is very quiet and not much crime

 
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Are these load calculations theoretical, or have you actually measured the loads?

Personally any hobby that was costing me £400 a month in electricity would have to be bringing me a lot of money back in, or I'd be finding a cheaper hobby!

 
Are these load calculations theoretical, or have you actually measured the loads?

Personally any hobby that was costing me £400 a month in electricity would have to be bringing me a lot of money back in, or I'd be finding a cheaper hobby!
I can peak up to 6Kw but it uses around 3-4Kw about the same as a tumble dryer I suppose

 
I can peak up to 6Kw but it uses around 3-4Kw about the same as a tumble dryer I suppose
I'd be running a cable slightly bigger than what you need at the moment and leaving it at that, then start looking at ways to make it pay, so you can afford to move it to somewhere else. It's nice to be able to do something, but lets be honest how long can you keep up paying that amount for electric, plus other things and your day to day living expenses? You seriously need to rethink this one.

 
I'd be running a cable slightly bigger than what you need at the moment and leaving it at that, then start looking at ways to make it pay, so you can afford to move it to somewhere else. It's nice to be able to do something, but lets be honest how long can you keep up paying that amount for electric, plus other things and your day to day living expenses? You seriously need to rethink this one.
Yeah I do It's gotten to much at this point, there's so much to sell if I were, luckily my mum helps with the electric as I still live with her being 17. I might put a few in storage and think about this before it gets to much

 
Just what are you using that much computing power for? a whole rack of servers, serving what?

By the way, do NOT even consider just connecting a SWA straight to a pair of henley blocks, that would be extremely dangerous. There is a LOT more to it than that.

 
Well I did a nhs server room last year and they only asked for a 32a supply - now I understand why they loose so many patient files they obviously need a bigger supply?! 

 

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