What size of sub-main cable and fuse for granny annexe?
 

Anyone advise what size of cable is required for a sub-main going to a
granny annexe? The Annexe/flat has an 8kw electric shower, a 4.5kw
cooker and the usual aray of kitchen appliances. Will 10mm² twin-core
and earth be adequate? It'll need it to pass the part-p certification
periodic test.

And what size of main fuse is suitable for this sub-main?

Thank you,

DaveH

What size of sub-main cable and fuse for granny annexe?
 

On Tue, 17 Apr 2007 17:40:55 +0100, DaveH
mused:


Anyone advise what size of cable is required for a sub-main going to a
granny annexe? The Annexe/flat has an 8kw electric shower, a 4.5kw
cooker and the usual aray of kitchen appliances. Will 10mm² twin-core
and earth be adequate? It'll need it to pass the part-p certification
periodic test.

And what size of main fuse is suitable for this sub-main?

The size on the cable depends on the length, installation method, load
etc... You have only given part of the information.

Part p isn't a periodic test. Who is doing the commisioning and
certification of the installation?

10mm does sound small though, I wouldn't use it as a submain for a
flat with electric cooking and heating.
--
Regards,
Stuart.

What size of sub-main cable and fuse for granny annexe?
 

"Owain" wrote in message
...
DaveH wrote:
Anyone advise what size of cable is required for a sub-main going to a
granny annexe? The Annexe/flat has an 8kw electric shower, a 4.5kw
cooker and the usual aray of kitchen appliances. Will 10mm² twin-core
and earth be adequate? It'll need it to pass the part-p certification
periodic test.

There's no such thing as a Part-P periodic test. You'll need either a
Design, Installation and Inspection and Testing Certificate, or a Minor
Works Certificate, OR a building control application to the local council.

And what size of main fuse is suitable for this sub-main?

If it's a bedsit type annex, integral to the house, with gas or other
non-electric heating, I'd suggest a 60A supply using 16mm.

For anything larger or if electric heating, treat as a separate dwelling
and provide 100A using 25mm. If the annex might ever be used separately
(rented out) then it might be worth biting the bullet and getting a new
supply from the street mains.

Be aware that T&E may not be acceptable with its reduced earth conductor
size, and submains are often done in MICC or armoured.

16mm T&E with a seperate 10mm earth seems normal in new build flats around
here.

Adam

What size of sub-main cable and fuse for granny annexe?
 

On Tue, 17 Apr 2007 21:26:22 +0100, Lurch
wrote:

On Tue, 17 Apr 2007 17:40:55 +0100, DaveH
mused:


Anyone advise what size of cable is required for a sub-main going to a
granny annexe? The Annexe/flat has an 8kw electric shower, a 4.5kw
cooker and the usual aray of kitchen appliances. Will 10mm² twin-core
and earth be adequate? It'll need it to pass the part-p certification
periodic test.

And what size of main fuse is suitable for this sub-main?

The size on the cable depends on the length, installation method, load
etc... You have only given part of the information.

The length of the sub-main cable will be 8 mtrs.

Part p isn't a periodic test. Who is doing the commisioning and
certification of the installation?

Haven't decided yet.

10mm does sound small though, I wouldn't use it as a submain for a
flat with electric cooking and heating.

The flat would not normally have any electric room heating as it has
central heating.

DaveH

What size of sub-main cable and fuse for granny annexe?
 

On Tue, 17 Apr 2007 21:22:51 +0100, Owain
wrote:

DaveH wrote:
Anyone advise what size of cable is required for a sub-main going to a
granny annexe? The Annexe/flat has an 8kw electric shower, a 4.5kw
cooker and the usual aray of kitchen appliances. Will 10mm² twin-core
and earth be adequate? It'll need it to pass the part-p certification
periodic test.

There's no such thing as a Part-P periodic test. You'll need either a
Design, Installation and Inspection and Testing Certificate, or a Minor
Works Certificate, OR a building control application to the local council.

And what size of main fuse is suitable for this sub-main?

If it's a bedsit type annex, integral to the house, with gas or other
non-electric heating, I'd suggest a 60A supply using 16mm.

For anything larger or if electric heating, treat as a separate dwelling
and provide 100A using 25mm. If the annex might ever be used separately
(rented out) then it might be worth biting the bullet and getting a new
supply from the street mains.

Seems worth thinking about.

Be aware that T&E may not be acceptable with its reduced earth conductor
size, and submains are often done in MICC or armoured.

OK, many thanks.

DaveH