Advice on Quotes for Wiring to Outbuilding - 2 options

[zerozero7]

Hi, Need some advice with 3 questions (Diagram below)
I am having a new 'Outbuilding' for storage which will be attached to the side of the house, replacing an existing 'Lean-To' and I need to decide on MDPE pipe for cables before the concrete is poured
It will be insulated Timber frame on a concrete slab. It will require a few socket outlets, light and maybe a low power heater. I only want to take the chill out the room, not heat it to 21c.
I will be inviting 2 electricians around to quote but a builder has suggested 2 options.

Option 1 was to take power from the back of a lounge socket to a fused connection unit which can then feed the sockets and lighting.

Option 2 (see Diagram below) Run SWA from the the house Consumer Unit, through the house wall, under the paving and through some pre-installed MDPE pipe, under Slab and into the Timber Wall cavity to a small consumer Unit.

1. Do either or both of these options seem acceptable or is there a better option?

2. How deep does the SWA need to be under the paving?

3. If I wanted to add a Garden Studio in the future, (Sockets, lighting and 2KW heater, no shower), if I went with Option 1 to supply the 'outbuilding', I suppose I would then run an new SWA from the Studio, along the fence, under the front Paving to the House Consumer Unit.
But, if I go with Option 2 and run SWA to the Outbuilding now, would I still run a new SWA from the Garden Studio back to the House Consumer unit or, as has been suggested, run some MDPE from the consumer unit in the 'outbuilding' out under the slab and so I could later run some SWA to take the power from there.

Thanks in advance.

 

[Lister1987]

What are you looking to run using the sockets? If you're getting a spark to do the work, get them to spec too, that way you know it'll be suitable.

Best practice would be new circuit from DB, If you come off the downstairs ring, you'll need to factor in existing usage on the circuit before whacking extra loads on.

 

[zerozero7]

What are you looking to run using the sockets? If you're getting a spark to do the work, get them to spec too, that way you know it'll be suitable.

Best practice would be new circuit from DB, If you come off the downstairs ring, you'll need to factor in existing usage on the circuit before whacking extra loads on.

Hello and thank you for your reply. Option 2 seems the sensible way to go but I'm not sure if it is overkill. I'm not entirely sure that I even need sockets in there as it is mainly for storage.
My concern is that option 2 with the dedicated SWA to consumer unit will cost me much, much more than option 1. If I only needed a light, a small 100watt bar heater and perhaps one socket ( to run a lawnmower or a drill) would option 1 be feasible. Just trying to seek advice before spark comes out so I can then discuss options without 'being led up the garden path'.

 

[littlespark]

The cable wouldn’t have to be buried deep, just enough to avoid damage.... and if it’s under slabs with no vehicular traffic, it’s not going to get much.
You don’t actually need to lift the slabs. If there’s no further doorway.
Surface clip low level and enter store behind the door. (If you don’t mind aesthetics)

If the further studio work is a 100% certainty to go ahead, then do option 2 now.

 

[zerozero7]

Thanks for the advice. Its good to hear that tbe SVA would'nt have to be buried too deep under the paving (foot traffic only). On a previous property it had to be 50cm deep under grass but I was hoping it would be shallower under paving. I like the idea of using SVA back to the board just so I have no limitations as to what I can use in the outbuilding and for future-proofing but option 1 will be much cheaper. I will get 2 quotes and make a decision now that I am clearer on the best options available to me. Thanks