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Author Topic: Getting power to a shed  (Read 25661 times)

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Offline jonny round boy

  • Posts: 3227
Re: Getting power to a shed
« Reply #30 on: September 19, 2014, 12:53 PM »
Quote from: wow on September 19, 2014, 05:13 AM
Not sure what the rules are over there, but in the U.S. your Cat5e would have to be underground rated even if it is contained in PVC / plastic pipe.

Oh - the same is true of coax for the 'telly' (hey, I'm trying?!). It also need to be underground rated and it also has a bright orange sheath.

IMPORTANT - I want to be clear that do not know the regulations or code in the UK,

In the UK, there are, as far as I'm aware, zero regulations when it comes to cat-5/6, co-ax, etc. You can pretty much do what you like with it!
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Festoolian since February 2006

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Wish list (in no particular order!): Anything not listed above....

Offline Brent Taylor

  • Posts: 471
Re: Getting power to a shed
« Reply #31 on: September 19, 2014, 01:33 PM »
I worked out of a site trailer with a 50 Amp hook-up that was tied to a RV style drop cord. The GC would provide the power outlet at the site. we were building schools ( 2 at once ) and were at the site for over a year. I have built Small houses (RV size)  that uses this same style hook-up. A hook-up like I am reading about in the other messages is the best way to go, get a sparky, have them do the brainy (read in stuff that can kill you) work and you do the bull work (stuff they don't want to do) and save a few pounds. The thing is if you need a temp set-up you might look at RV/ marine hook-ups. Brent
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Offline richy3333

  • Posts: 201
Re: Getting power to a shed
« Reply #32 on: September 20, 2014, 10:47 AM »
Section 528 of the UK Regs deals with the proximity of wiring systems to other services.
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Offline Pennywise

  • Posts: 2
Re: Getting power to a shed
« Reply #33 on: September 27, 2014, 06:42 PM »
We usually run a few lengths of this in

http://www.pipes-underground.com/cable-ducting.html

, you'd probably be looking at the 32mm stuff one for the SWA or HiTuff the other for your catV, it's smooth bore so cables glide in, and it pretty much future proofs you for any additions. Me personally I'd put a metal clad DB in the shed and do everything in high impact pvc conduit with metal clad socket outlets, or if you wanted to really push the boat out galv conduit :). Cable sizing as mentioned above needs calculation, 4mm to 6mm would be a good starting point.

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Offline TBR

  • Posts: 121
Re: Getting power to a shed
« Reply #34 on: October 01, 2014, 04:02 AM »
I just started ringing around electricians yesterday. 1 chap said that it would take  one day and he would charge  £180 plus materials. Hopefully next week ill be able to get some of them to pay a visit so they can advise the best way to dig through the concrete or reroute around the house. I've ordered a catalogue from tlc so that when they are round we can build a shopping list.

 i found on youtube interesting video about how to get a pull cord through a pipe using a vacuum cleaner and some polystyrene on a hook to act as a piston. Very useful tip !
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Normal people... believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet.

Offline TBR

  • Posts: 121
Re: Getting power to a shed
« Reply #35 on: October 01, 2014, 04:05 AM »
Here are some more detailed photos...
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Normal people... believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet.

Offline TBR

  • Posts: 121
Re: Getting power to a shed
« Reply #36 on: October 11, 2014, 02:40 PM »
Finally, I got an electrician round last week and he's just quoted £1000 for the job. I asked for 2 security lights on the house, a light and 5 double sockets in the shed.

He looked at the concrete and i was worried that some of the underground pipes my crack, so we decided it would be best to run the armoured cable behind kitchen units, out through the back wall, under the doorstep and around the house to the other side of the garden and then down to the shed.

3 days labour at £240 per day. The rest is materials of which £140 for 50m of 6mm swa. £40 for a 2 way consumer unit.

Looking for ways to get this cost below £300.



Another recommended semi retired electrician quoted £30 an hour. But he couldn't do any certification work because he is no longer a member of necessary body. He used to be certified but nowadays he does less work and so is not worth it for him to pay his membership.
« Last Edit: October 11, 2014, 02:49 PM by TBR »
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Normal people... believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet.

Offline richy3333

  • Posts: 201
Re: Getting power to a shed
« Reply #37 on: October 11, 2014, 03:00 PM »
£240 a day seems cheap to me for London, but 3 days is excessive for all that work. I'd say 2 tops. If breaking the concrete out is part of that time can you not dig the trench to save a few pounds? Else can he not use a catinery wire to save burying the cable?

£140 for 50m of 6mm doesn't sound bad
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Offline TBR

  • Posts: 121
Re: Getting power to a shed
« Reply #38 on: October 11, 2014, 03:03 PM »
Quote from: richy3333 on October 11, 2014, 03:00 PM
£240 a day seems cheap to me for London, but 3 days is excessive for all that work. I'd say 2 tops. If breaking the concrete out is part of that time can you not dig the trench to save a few pounds? Else can he not use a catinery wire to save burying the cable?

£140 for 50m of 6mm doesn't sound bad
No digging for that quote. We aggreed it might crack a pipe underground
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Normal people... believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet.

Offline TBR

  • Posts: 121
Re: Getting power to a shed
« Reply #39 on: October 12, 2014, 11:50 AM »
Quote from: E30Mark on August 09, 2014, 12:40 PM
There are a few factors to be considered here!

All electrical installations should comply with BS7671:2008

What type of fuse-board do you already have in the house?... Does it have a spare way for another MCB? Do you have RCD protection on the existing fuse-board?

A 2kw load over 80' will produce a volt drop of around 6V with a 1.5mm2 SWA cable. Maximum cable load would be approx 16A

A 2.5mm2 SWA will have less volt drop and a max load of approx 21A

Without seeing the whole length of where you plan to run the cable it's hard to give a complete answer, but basically I'd run a 2.5mm2 SWA clipped to the house wall so you don't have to dig past the drains, and then bury it where necessary. The regs don't give an exact depth to bury the cable, but state it must be a 'suitable depth'.... rule of thumb is 18" down.

Your not allowed to clip to a fence, as it's not deemed a permanent structure, funnily enough, your allowed to leave the armoured cable laying on the surface un-buried...

An electrician has quoted for 6mm2 SWA. It's almost twice the price of 2.5mm2. £110 as opposed to £60. Just wondering if there is a good reason for this?
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Normal people... believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet.

Offline TBR

  • Posts: 121
Re: Getting power to a shed
« Reply #40 on: September 12, 2016, 08:41 AM »
Finally made the decision to put in the SWA cable to the shed. One of the electricians that has quoted me has recommended to install separate dual RCBO with enclosure to protect the circuit to the shed (materials required 25m tails x 2mm, 1 x Henley block and 16mm earth cable). He said that it would be best if the shed was on its own RCD because if the cable to the shed trips the RCD often then it will keep knocking out power to half the house.

Just wondering if this is really necessary.
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Normal people... believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet.

Offline GarryMartin

  • Posts: 1923
Re: Getting power to a shed
« Reply #41 on: September 12, 2016, 01:31 PM »
You clearly work at the same speed as I do...  [big grin]

Assuming you mean 2m of 25mm [wink], it's actually a neat way of doing it and the way I've discussed doing mine with my electrician. As you've been told, it removes the issue of nuisance tripping of your main RCD in the house if there are issues in the external building.

I actually have a board in the house that's full of RCBOs so it didn't quite make the same difference for me, but getting the SWA to that board (on an inside wall) versus the Henley block from the main fuse entry point (on an external wall) was just much easier. It also means I can easily put in a 230V 16A socket in the garage where the entry point is too, so win win.

Factoring in voltage drop, and assuming 230V, 6mm SWA in PVC or XLPE will cope with a 7-8kW load over that 50m run.
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Offline richy3333

  • Posts: 201
Re: Getting power to a shed
« Reply #42 on: October 23, 2016, 01:21 PM »
Quote from: TBR on September 12, 2016, 08:41 AM
Finally made the decision to put in the SWA cable to the shed. One of the electricians that has quoted me has recommended to install separate dual RCBO with enclosure to protect the circuit to the shed (materials required 25m tails x 2mm, 1 x Henley block and 16mm earth cable). He said that it would be best if the shed was on its own RCD because if the cable to the shed trips the RCD often then it will keep knocking out power to half the house.

Just wondering if this is really necessary.

Hi.

If there is no spare capacity in your existing CU then the main tails can be split to supply 2 CU's. Tail size to the new board will be dependant on the type of earthing system you have at the property.

Re the use of RCBO's in the new board that supplies the shed - in simple terms there is no need for this if using SWA cable. An appropriately sized OCPD is all that's required. Then use an RCD or RCBOs in the board in the shed. If you use RCBOs on the supply circuit and in the shed an RCD, there will be no discrimination over which RCD/RCBO trips in the event of an Earth fault.

I assume the electrician is satisfied there are no extraneous conductive parts in the shed that require bonding?

BTW both new CU's will now need to be metal clad as of January 2016 so the ones previously discussed won't be suitable.

Also check if the work requires notification to BC as per part P of the English building Regs.

HTH


« Last Edit: October 23, 2016, 01:32 PM by richy3333 »
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