Pub Shed Power set up.

[Alan Stirrup]

Hi all,

New year greetings and let's hope this insidious Covid (currently isolating) comes to an end this year.

I've checked the other shed power threads but they don't cover my question, I'm currently building a log cabin pub in my garden and will need power for approximately six double sockets ringed to a cu in the shed. One of these will power a twin line chiller but I haven't bought it yet so I don't know the draw to do an accurate calculation, the remaining sockets will power a table light and bar pump lights. I'll also be having three pendant lights above the bar and one centre main light.

I'll be using 2.5 metre SWA which I'd like to connect to a CU 18 metres away in my garage, at present this CU powers one double socket and one small strip light both seldom used. The garage CU is connected directly to the main fuse box in the house, however, I have no access to get to the back of the fuse box to run the feed from there which would be my preferred method.

My question is would this be safe and acceptable? I know that this is part p notifiable so I will be getting a qualified spark to sign it off but I'd welcome any help and guidance as money is extremely tight at the moment so I need to do as much of the ground work as possible myself.

 

[buzzlightyear]

Considering a. Shed or out building comes under part P building control.
Very doubtful a spark will sign off your work.

 

[timhoward]

I'm afraid this is a vague answer - as more information would be needed to actually confidently answer the question.

Providing power to an outbuilding needs to balance a large number of things, and it isn't that easy to get it right if you're not regularly designing circuits.
You need a big enough cable for the load, and to retain a high enough voltage for the distance, with big enough conductors to allow a low enough impedance to result in a large enough fault current to ensure that if something bad happens the over current protective device (that has been chosen to play ball with everything so far) will operate.
In addition there's other stuff rocking around with earthing system types, and requirement to bond certain services, in turn dictating certain cable sizes.
As you aren't starting at the origin there are yet more factors in your case too. The capacity of the supply to the intermediate consumer unit comes into it, the earthing system there comes into it, as does the fact that you don't want to be running all the way to the house to reset an RCD if you are in the pub and it all goes dark. So discrimination of additional protection needs thinking though as well, making sure that a fault in the pub doesn't take out half the house.

All that to say, you really need a sparks to visit and design the new circuit. Cable is very expensive and you don't want to buy it twice. They may well agree that you can run the SWA for them (I would!). They may well let you do some first fixing. If you strike up the right rapport maybe even more.

But ultimately they are going to have to put their name to it on the certificates and for the building regs notification so discussing the plan with a sparks at the beginning is the best way forwards.
All the best with the project, it sounds interesting!

(By the way, as this concerns Liverpool and a pub I'll be interested to see if a certain forum member declares an interest in this project!)

 

[123]

How are you planning on heating this bar?

2.5mm SWA seems totally pointless to add a consumer unit in the bar with that,easier to fuse down the lighting and not bother with it...but it doesn't give you much scope

 

[Alan Stirrup]

How are you planning on heating this bar?

2.5mm SWA seems totally pointless to add a consumer unit in the bar with that,easier to fuse down the lighting and not bother with it...but it doesn't give you much scope

I have a log burner which I'm currently installing.

 

[pc1966]

I would tend to agree with @123 that for 2.5mm SWA you can only really power a few sockets anyway, so just have it fed off a 20A RCBO or similar, and at the log cabin bar use a FCU with 3A or 5A fuse to power the lights from that.

At an absolute push the SWA could be terminated in a suitable box inside the home or existing garage and a 13A plug with 1.5mm flex used to feed it, sort of extension lead on steroids. The only and absolute proviso there is the sockets must have RCD protection.

But given the cost and effort for the whole project you would be best to get a sparky to do the new circuit and Part P notification aspect so you have the full 20A to play with for the future. They can look at the current house/garage CU setup and advise on what sort of approach is going to be best for you.

 

[UNG]

I have a log burner which I'm currently installing.

While the log burner will heat the shed when it's being used what about when it is not being used have you considered the damage damp and frost might do if you have no background heating during those periods

 

[Rockingit]

To give one answer - an in-line chiller is normally around 1kW / 4A. However, as others have said, there’s a lot more to this story than just that. As you’re starting your supply from ‘B’ rather than the origin you’ll already be at a disadvantage depending on how that was setup and what the sparky maths is at that point. If all you’ve got is a chiller, some lights and iPod disco then you possibly could get away with a 2.5mm supply, however for the sake of a handful of quid over that short length I’d suggest using 4mm at least. I’m also going to guess that you’ll end up having to rely on RCD’s for protection rather than being within the Zs allowances for ADS, fundamentally that’s fine except I very much doubt that whoever installed your house to garage supply considered what we call discrimination, which will just get worse (so basically you could end up with a fault in the shed tripping out the whole house, not the local CU). As others have said, this really does need looking at by an experienced and reputable sparks. @telectrix likes his beer and is in your neck of the woods……