Shed install. Splitting tails

[BenSparky8]

Hi guys,

Wondering if you could give any advice. Started a job today doing a shed install. They want a 6mm swa supply. The original plan was to come off of an MCB in the fusebox but it’s not going to be very accessible without too much damage.

Is there any ideas in what I could do in the meter box? Was thinking maybe a 40a isolator of some kind to take the swa from?

Thanks

 

[suffolkspark]

Hi guys,

Wondering if you could give any advice. Started a job today doing a shed install. They want a 6mm swa supply. The original plan was to come off of an MCB in the fusebox but it’s not going to be very accessible without too much damage.

Is there any ideas in what I could do in the meter box? Was thinking maybe a 40a isolator of some kind to take the swa from?

Thanks

Can you not go through the meterbox, or is the cu not on the reverse? Even removing that second random main switch I don't think you'll have room for a dual block and a switch fuse

 

[Petej999]

Surely it's not "what they want" it's what is correct for the safety of the install , that's your job when you submit a price and design for the work. The 6mm they want may not be the correct size for the rest of the requirements of the install,

 

[BenSparky8]

Can you not go through the meterbox, or is the cu not on the reverse? Even removing that second random main switch I don't think you'll have room for a dual block and a switch fuse

No for some reason they’ve put it not on the reverse wall. I’m thinking the same I’ll struggle with a 40a fused unit… can’t think of many other options.

Could I put just a 40a DP main switch/RCD in a little 1 way enclose, would that be acceptable? 25 tails feeding it and 6mm swa out bottom?

 

[loz2754]

I'm guessing the 63 amp MCB is because the tails are longer than 3 metres.
Either way there's not a lot of room in there.

 

[suffolkspark]

I'm guessing the 63 amp MCB is because the tails are longer than 3 metres.
Either way there's not a lot of room in there.

I missed that, just thought is was another main sw, but yea mighty tight in there

 

[Dustydazzler]

Oh dear , what a mess. Main Iso and then a DP mcb because someone needed a long run of tails through the house to the consumer unit/

Why oh why can't the consumer unit simply do on the reverse of the meter cupboard to the tails can be simply pulled through the wall and straight into the board without having to weave through the fabric of the build

Back to the OP, splitting up the tails an having a big old henley block in there along with your new swa feed and mini consumer unit would look a right pigs ear imo

 

[BenSparky8]

Oh dear , what a mess. Main Iso and then a DP mcb because someone needed a long run of tails through the house to the consumer unit/

Why oh why can't the consumer unit simply do on the reverse of the meter cupboard to the tails can be simply pulled through the wall and straight into the board without having to weave through the fabric of the build

Back to the OP, splitting up the tails an having a big old henley block in there along with your new swa feed and mini consumer unit would look a right pigs ear imo

Exactly, I really can’t understand why it wasn’t just put on the other side of that wall… all of that trouble for no real benefit

 

[timhoward]

I think the first thing is to work out the reason for the C63.
If it's the tails length, as already mentioned, can the fusing down be other side of wall?
If it's because of 16mm tails, can the tails be upgraded, or (if desperate) can the supplier fuse be de-rated so the C63 isn't necessary.

Only other idea would be if you can squeeze a 2 way CU in there replacing both isolator and C63, but I'm not optimistic about that.

What power is actually needed in the shed? Do they really need 40-50A down there? I'm normally all for doing it properly and providing a fused supply from the origin but I'd be looking at every possible alternative in this situation.

 

[Dustydazzler]

As above , if you could do away with the 63a mcb completely and put in some sort of 2 way consumer unit to feed the house and a shed then you could make a dogs dinner look not too bad

If it were my house , I would probably do the above and have the house on a 63a mcb or even a 50a mcb and the shed on a 32a or 20a

 

[mainline]

Exactly, I really can’t understand why it wasn’t just put on the other side of that wall… all of that trouble for no real benefit

Is that cabinet surface mount cant see from the pic, if so can't you put another next to it

 

[timhoward]

As above , if you could do away with the 63a mcb completely and put in some sort of 2 way consumer unit to feed the house and a shed then you could make a dogs dinner look not too bad

If it were my house , I would probably do the above and have the house on a 63a mcb or even a 50a mcb and the shed on a 32a or 20a

The fun is finding a 2 way CU that fits in width-wise, has 100A main switch, but also has enough space to give you any hope of getting 16mm tails in and around to the top. A lot of them simply wouldn't have room.

This might work

Metal Clad Consumer Units Fuse Boards Amendment 3 | CEF

13.6 cm wide and comparatively spacious

 

[mainline]

The fun is finding a 2 way CU that fits in width-wise, has 100A main switch, but also has enough space to give you any hope of getting 16mm tails in and around to the top. A lot of them simply wouldn't have room.

This might work

Metal Clad Consumer Units Fuse Boards Amendment 3 | CEF

13.6 cm wide and comparatively spacious

Agreed

The fun is finding a 2 way CU that fits in width-wise, has 100A main switch, but also has enough space to give you any hope of getting 16mm tails in and around to the top. A lot of them simply wouldn't have room.

This might work

Metal Clad Consumer Units Fuse Boards Amendment 3 | CEF

13.6 cm wide and comparatively spacious

Seems overkill for a shed supply not knowing the size etc, but I am assuming it's a socket and a light.

 

[mainline]

Agreed

Seems overkill for a shed supply not knowing the size etc, but I am assuming it's a socket and a light.

Used loads of those, get them cheap on Amazon with 3 fuse sizes.
As said, it's the Henley blocks and tail routing that takes up the space when using more than one.

 

[123]

I take it when it came to getting the ducting for the DNO supply, a big hammer was the only tool available?

Never seen the cut out mounted like that before either, it certainly doesn't look the most secure mounting. Also never seen the duct left open and not filled with a putty of some sort.

 

[Dustydazzler]

I take it when it came to getting the ducting for the DNO supply, a big hammer was the only tool available?

Never seen the cut out mounted like that before either, it certainly doesn't look the most secure mounting. Also never seen the duct left open and not filled with a putty of some sort.

Almost looks like the builder was left to get the DNO cable up inside the meter housing, the smart meter came first and when the DNO came to connect there was no room left to fix the head back

Either way it is pretty rough as ...

 

[brianmoooore]

Angled back head like that is common enough in flush mounted boxes to avoid sharp bends in the cable.
Strangely, the Western Power used that arrangement in one of my supplies in a surface box. Service cable comes out of the ground and rises up to the cabinet a good six inches away from the wall.