wholesalers mcb

[yesitsashock]

Im looking to put a supply out in a mancave, the earthing arrangement is tns. At the supply there is iscos installed so I was going to take a supply out of the iscos into a 40 amp DP MCB and run a 6mm T+E surface piped along an outside wall. I will be installing a 40A 30mA RCD in the mancave. My query is the wholesalers dont stock 40 amp double pole MCB's, I cant find anything wrong with what im planning in the regs.
The fact the wholesaler doesnt stock them has sorta through me a bit. Do I need to protect the supply cable with an RCD in the house aswell.
Thanks in advance.

 

[telectrix]

T/E is not advisable outdoors. best use SWA. could start with T/e indoors and then switch to SWA in adaplable box. making sure that the armour is earthed, even if not used as cpc. RCD at supply end only needed if the first section of T/E is buried < 50mm deep in wall/s. you could start with a 40A S/P MCB into a D/P switch

 

[yesitsashock]

T/E is not advisable outdoors. best use SWA. could start with T/e indoors and then switch to SWA in adaplable box. making sure that the armour is earthed, even if not used as cpc. RCD at supply end only needed if the first section of T/E is buried < 50mm deep in wall/s. you could start with a 40A S/P MCB into a D/P switch

point noted about the cable type. I will have to install a 3 module cu with a 80a DP MCB and a 40a SP MCB.

 

[telectrix]

no. 40A single pole MCB, then into a 40A d/p switch. this give D/Pisolation for the exterior lghts.

 

[brianmoooore]

A better solution is a 45A metal switch/fuse in the house, SWA all the way to the shed, and then a small CU with RCD protection for the shed circuits.

 

[yesitsashock]

A better solution is a 45A metal switch/fuse in the house, SWA all the way to the shed, and then a small CU with RCD protection for the shed circuits.

Thats the way i want to do it but im struggling to get a 40/45a mcb/fuse switch for an OCPD. The local wholesale only has 40a RCD's.

 

[brianmoooore]

It's not ideal to use a MCB at the house end of the cable. It may switch off at the same time as a lower rated MCB in the shed when a fault occurs. A switch/fuse, such as the one in my link, gives better discrimination, and will take a SWA gland direct.

Wylex 45A Metalclad Switchfuse

Wylex 45A Metalclad Switchfuse

www.electricals247.co.uk

 

[telectrix]

It's not ideal to use a MCB at the house end of the cable. It may switch off at the same time as a lower rated MCB in the shed when a fault occurs. A switch/fuse, such as the one in my link, gives better discrimination, and will take a SWA gland direct.

Wylex 45A Metalclad Switchfuse

Wylex 45A Metalclad Switchfuse

www.electricals247.co.uk

too expensive and space my be an issue. I prefer this with a 45A fuse.:

 

[brianmoooore]

You'll struggle to attach a SWA gland to that!

 

[buzzlightyear]

You'll struggle to attach a SWA gland to that

not if you use a metal adaptable box be for that.

 

[brianmoooore]

Be a LOT easier to use Wylex unit in my link!
Must have fitted well over a hundred of them over the years, in their various guises.