CU to Outbuilding - 45m run - 8.5kW Shower.

[ToastyToes]

Hello all,

Planning for an outbuilding at the rear of the garden, approximately 45m run from the current CU.

I want to install an electric shower in the outbuilding (8.5kW) and use it to run office equipment (computer and TV).

I have 14m of 16mm 3 core SWA from a previous job. Could I use this to run from the CU to the garden and use a second length to finish the run to the outbuilding? Is 16mm thick enough? The cable will lay under joists for 10m, screed for 5, and underground for the last 30m.

The outbuilding will have its own CU for shower, ring and lighting.


Thank you!

 

[JohnW2]

... The cable will lay under joists for 10m, screws for 5, and underground for the last 30m....

"Screws for 5" ???

Kind Regards, John

 

[ToastyToes]

"Screws for 5" ???

Kind Regards, John

Screed... phone auto correct..

 

[JohnW2]

Screed... phone auto correct..

Fair enough - how deep under screed?

My first comment/question would be to ask if you have an electric shower in the house. If so, I think you'll find that that you theoretically should seek DNO permission to have two (or more!) electric showers run off one domestic electrical installation.

Kind Regards, John

 

[ban-all-sheds]

I have 14m of 16mm 3 core SWA from a previous job. Could I use this to run from the CU to the garden and use a second length to finish the run to the outbuilding? Is 16mm thick enough? The cable will lay under joists for 10m, screed for 5, and underground for the last 30m.

Given that you have to ask that question, what credible method will you tell your council will be the way you'll ensure compliance with Part P when you apply for Building Regulations approval?

 

[ToastyToes]

Fair enough - how deep under screed?

My first comment/question would be to ask if you have an electric shower in the house. If so, I think you'll find that that you theoretically should seek DNO permission to have two (or more!) electric showers run off one domestic electrical installation.

Kind Regards, John

No, the outbuilding will be the only one.

 

[sparkwright]

How will join the two lengths of cable?

Underground joints are ideal, for the sake of a measly 14 metre length.

 

[333rocky333]

How will join the two lengths of cable?

Underground joints are ideal, for the sake of a measly 14 metre length.

NOT ideal!

 

[sparkwright]

Yes, NOT ideal! Typo...

 

[ToastyToes]

How will join the two lengths of cable?

Underground joints are ideal, for the sake of a measly 14 metre length.

NOT ideal!

I can bring the cable up and terminated in a box with gel if need be. 14m of cable still cost me £75!

 

[Notch7]

How are you dealing with the earth?

 

[ericmark]

16 mm² with 6.9 volt drop looking at around 65 meters with 40 amp load, so can't see a problem.

 

[ban-all-sheds]

Toasty - what are you planning to tell your council will be the way you'll ensure compliance with Part P when you apply for Building Regulations approval?

 

[ToastyToes]

Toasty - what are you planning to tell your council will be the way you'll ensure compliance with Part P when you apply for Building Regulations approval?

Would I need to tell the council if a sparky tests and signed it off?

 

[ToastyToes]

How are you dealing with the earth?

I'm not sure what you mean? Theres an earth in the SWA.