Outbuilding with multiple supply

[captaincaveman]

Hi lovely people.
Just thinking aloud here wondering if anyone has any points I should consider.
Been to do a quote on an outbuilding which has had an electrical supply for some time for lights & a couple of sockets. The building is basically a lounge with toilet & utility room.

The owner wants a shower in there (8kw) and has laid a new 10mm cable along the garden wall from the ccu to the outbuilding just for supplying the shower and now wants it connecting up. The cable enters the outbuilding at the opposite end to the existing supply.

I need to sit down and plan a design but have never supplied an out building which already has a supply and there's a couple of things I need to look into. Such as being able to isolate both supplies simultaneously. Whether to bond both supplies at the outbuiling side etc, etc...

Any suggestions or recommendations for me to take into account would be gracefully appreciated.

 

[Octopus]

I would be asking the customer the reasoning behind the cable they bought ................... is it SWA or T&E?

 

[captaincaveman]

SWA

 

[Octopus]

Why would you need to isolate both supplies "simultaneously"?

 

[captaincaveman]

I would see it as good practrice. Otherwise DIYer Joe Blogs may isolate one supply to do some maintenance and have a nasty suprise

 

[Octopus]

Good practice goes out the window when DIY Dave installs the cable!

Not sure how you can achieve this ................ how does the customer expect you to connect this cable he bought to the supply?

 

[Spoon]

Is the water pipe for the shower copper or plastic?
I presume it's a new circuit? Who will be doing the notification?

 

[Leesparkykent]

Could be
Done with a contactor and the coil fed from the Board in the outbuilding. When you knock the main switch off it cuts the power to the coil and disconnects the supply to the shower.

 

[Deleted member 9648]

It wont be 'multiple supplies', it'll be two circuits from a single source of supply. Just label and identify distribution equipment accordingly.

 

[Deleted member 26818]

Yes, I would not be concerned about linking the two isolators.
I imagine you would be using an up front RCD for the shower anyway?

 

[willy fixit]

What is the earth arrangement? - It should be TT at the outbuilding.
Could you use the 10mm for everything and disconnect the old supply?

 

[Pete999]

What is the earth arrangement? - It should be TT at the outbuilding.
Could you use the 10mm for everything and disconnect the old supply?

I was thinking that as well willy but without eyes on the install, it would be a tall order to come to a safe decision on that, but yes it is a good idea.

 

[telectrix]

What is the earth arrangement? - It should be TT at the outbuilding.
Could you use the 10mm for everything and disconnect the old supply?

just what i was thinking.

 

[Deleted member 9648]

Why should it be TT at the outbuilding?

 

[willy fixit]

Fair comment WP I should've worded it as below.

What is the earth arrangement? - Should it be TT at the outbuilding?
Could you use the 10mm for everything and disconnect the old supply?

I think I would put a rod in to bond the water supply (If it's extraneous) - I guess it depends on how easy it is to run a bond to the MET.

 

[Spoon]

I think the OP has run off. I seem to have this affect on people when I post stuff...