Isolator and/or HBC?

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beemer

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I will soon be connecting a new sub board in an extension by SWA from an enclosure fed from a Henly box next to the main cut-out in the main house.

My SWA is 16mm, and I intend to protect the SWA with a 63A isolator.

Do I need a fuse as well in the enclosure?

The earth system is TN-S, and the extension is part of the main house, and the SWA runs on the outside of the main house along the wall up high (first floor) and enters the ceiling area of the new extension.

 

ian932

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I will soon be connecting a new sub board in an extension by SWA from an enclosure fed from a Henly box next to the main cut-out in the main house.My SWA is 16mm, and I intend to protect the SWA with a 63A isolator.

Do I need a fuse as well in the enclosure?

The earth system is TN-S, and the extension is part of the main house, and the SWA runs on the outside of the main house along the wall up high (first floor) and enters the ceiling area of the new extension.
At a guess the 16mm SWA is more than 3m long. If it is then you would need to use a switch/fuse to protect the SWA cable at the supply end and the total length of tails etc. from the supply fuse to the S/F needs to be less then 3m to.

 

beemer

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That's the problem .... I have a steel enclosure with Isolator switch and HBC fuse, but the box is too big for the space next to the Supply (within 1m). I don't seem to be able to find an enclosure small enough (200mm X 200mm space) which would take a switch and fuse. :(

 

ian932

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That's the problem .... I have a steel enclosure with Isolator switch and HBC fuse, but the box is too big for the space next to the Supply (within 1m). I don't seem to be able to find an enclosure small enough (200mm X 200mm space) which would take a switch and fuse. :(
Cant you use something like this ? 60 Amp Switchfuse SP N Insulated - Ex Fuse

 

beemer

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Would be great...

I would be terminating SWA into it, would it take a gland?

 

beemer

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Have connected SWA into metal Proteus box with isolator and HBC fuse.

The box is a lot bigger than I really wanted to fit but I managed to find a space for it.

I am very surprised that a smaller unit in steel could not be found to my requirements. Surely, this must be a common installation, sub board via SWA??

 

ian932

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Have connected SWA into metal Proteus box with isolator and HBC fuse.The box is a lot bigger than I really wanted to fit but I managed to find a space for it.

I am very surprised that a smaller unit in steel could not be found to my requirements. Surely, this must be a common installation, sub board via SWA??
Look hard enough and yee will find !!

http://www.qvsdirect.com/Protek-1-Pole-Metal-Clad-Switch-Fuse-63A-pr-22629.html

Best Wylex 108M Wylex 108M Metalclad Switchfuse 45/60A Kent Products

There is a limit on the size you can make these units to still leave room for wiring.

As Batty said install a smaller insulated unit via through box, I sometimes use 100x100 adaptable box close coupled to the switchfuse.

 

beemer

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