shed/outbuilding

[sealeon]

Hi anyone tell me what regs apply to putting a two way board in abrick shed about 5 meters from the house the board is to feed a couple of sockets and a single light can I use a catenary wire from the main board or does cable have to be burried does it need an earth rod I have a spare way in the board
cheers

 

[davy_owen_88]

Hi anyone tell me what regs apply to putting a two way board in abrick shed about 5 meters from the house the board is to feed a couple of sockets and a single light can I use a catenary wire from the main board or does cable have to be burried does it need an earth rod I have a spare way in the board
cheers

Regs? BS7671:2008 chapters 11 - 63, appendix 2-11, and 12-15.

Do you want page numbers to go with that?

Firstly this work is notifiable so you must notify your BCO before you start.
Do you have any experience carrying out electrical work? This job is quite involved.

What consumer unit do you have? Do you have RCD protection? Do you have a means of isolating the whole supply? What earthing arrangement do you have? What is the maximum demand from the shed? What route would the cable need to take through your house before it could emerge outside? Will there be any plumbing work present at the shed?

You can use a caternary wire to suspend the cable, but you need to answer the questions above before I can give you any more advice.[/b]

 

[sealeon]

yes have experience mainly com/ind not domestic to 17th.
cu is memora?
BS1361 type fuses
no RCD in main board 2 additional RCDs for shwer/sockets
supply is 2 cables in one to fuse one to N with earth terminal TNC-S[?]
Run cable through utility cupboard in trunking and out into meter cupbard as earth to water is
need one socket and one light rather have seperate circuits than light on spur
does that help

 

[sealeon]

sorry no plumbing in shed although metal roof[bond?]
was thinking t and e to metal stop end box on outside wall then glanded swa [4mm not sure I like joining two cables for same supply though thats why I thought catenary] to two way cu in shed with rcd main switch with new addional rcd box in house the meter cupboard is closer but not sure I wwant conect tails to meter and put rcd/main swich in there or whether I can

 

[ban-all-sheds]

Hi anyone tell me what regs apply to putting a two way board in abrick shed about 5 meters from the house

The Wiring Regs I guess you know about.

The Building Regs also apply - as Davy said this work is notifiable. You can read all about that here:

//www.diynot.com/wiki/electrics:part_p

There's no legal recognition of qualified but unregistered sparks - if you aren't registered to self-certify Building Regulations compliance then you're treated as a DIYer. But if your council is one of the miscreants that tries to make non-registered people pay for their own I&T you might be able to sidestep that fight by getting them to accept your EIC. But you'll still need to notify them in advance...

can I use a catenary wire from the main board or does cable have to be burried

No difference there to what's required in a commercial environment - the regs are the same for domestic.

does it need an earth rod I have a spare way in the board
cheers

Ditto.

supply is 2 cables in one to fuse one to N with earth terminal TNC-S[?]

Sounds like it, if the main earth comes from the cutout not the sheath.

In which case if you think the metal roof is an extraneous-conductive-part you either need to bond it (bye-bye 4mm² SWA, hello 10...) or make the shed TT.

Run cable through utility cupboard in trunking and out into meter cupbard

Got room in that cupboard for an isolator, DP Henley and a switchfuse?

was thinking t and e to metal stop end box on outside wall then glanded swa [4mm not sure I like joining two cables for same supply though thats why I thought catenary]

If you are going to connect to the house CU, and you can't terminate the SWA there, then instead of joining like you suggest could you put the adaptable box adjoining the CU, gland the SWA there but leave the cores long enough to reach inside the CU?

to two way cu in shed with rcd main switch with new addional rcd box in house

What's the RCD in the house for?

the meter cupboard is closer but not sure I wwant conect tails to meter

What could go wrong?

You're right - pulling the fuse is not to be recommended, but depending on your experience, its condition and what PPE you have access to it might be a decision you make.

and put rcd/main swich in there or whether I can

You're not supposed to, but as long as you don't damage, obstruct, or otherwise compromise the DNO's kit I doubt they'd come after you for it.

DISCLAIMER -

IANAL or a DNO employee.
Your experience may vary.
The value of my advice can go down as well as up.
This forum may contain nuts.
Don't eat yellow snow.

 

[Chri5]

IANAL or a DNO employee.
Your experience may vary.
The value of my advice can go down as well as up.
This forum may contain nuts.
Don't eat yellow snow.

Subtle.........

 

[sealeon]

would it be best in this case to remove tails to house cu from meter and conect into henly[link box?]and replace with new tails from meter to link box.Add new tails of same size from henly[link] to rcd main switch in meter cupboard.Then a 2 core 4mm from that rcd[to protect main fuse in case of cable damage not likely I know as it will be on a catenary]to new cu in garage [with another rcd?]with earth rod conected with 10mm earth.
I guess it could be a good idea to get supplier to fit an isololating switch befor the link boxes.The height of catenary would be dependent on the area as no access to vehicles this would be 3 or 3.5 meters from ground
My meter is on the outside wall
Or should I forget the RCD in shed and just have RCD in meter cupboard and run a three core to shed from there and take the earth connection to rod from within the RCD enclosure

 

[ban-all-sheds]

would it be best in this case to remove tails to house cu from meter and conect into henly[link box?]and replace with new tails from meter to link box.

Got room in that cupboard for an isolator, DP Henley and a switchfuse?

Add new tails of same size from henly[link] to rcd main switch in meter cupboard. Then a 2 core 4mm from that rcd[to protect main fuse in case of cable damage not likely I know as it will be on a catenary]

Will an RCD provide overload protection for the 4mm² SWA?

If no, is 4mm² OK on the 80/100A service fuse you probably have?

to new cu in garage [with another rcd?]with earth rod conected with 10mm earth.

Why an RCD at each end?

Why make the garage a TT installation, particularly given the care you'll need to take with the armour at that end?

I guess it could be a good idea to get supplier to fit an isololating switch befor the link boxes.

Unless you want to be kneeling down there with live tails in your hand, it's more than a good idea....

 

[sealeon]

IANAL or a DNO employee.
Your experience may vary.
The value of my advice can go down as well as up.
This forum may contain nuts.
Don't eat yellow snow.

Subtle.........

I bet your the same bloke who writes them things on site toilet walls aint you

 

[davy_owen_88]

As BAS has mentioned the requirement to provide main equipotential bonding to the metal roof depends on whether it can introduce a potential, and this depends really on how well it is insulated from the ground and its general construction - is it supported with I-beams that allow it to introduce a potential? If it is just a copper roof supported on timber rafters resting on a timber wallplate sat ontop of a masonry wall then it's unlikely to introduce a potential so bonding is not necessary.

You don't want to have an RCD at the house end if you can help it because you don't want to have to travel back to the house in the dark should it trip.

I recommend that you get a metal adaptable box as suggested earlier and put that next to the consumer unit. Terminate your SWA into that and run the inner conductors and sheath into the CU. You will need to connect the metal box and the armour to the main earth terminal in the CU too.

As the shed appears to have quite a low maximum demand I wouldn't bother with the switchfuse or henleys and I would just feed the SWA from a suitable MCB - 32A will be fine for a 6A lighting circuit and a 20A radial circuit for the sockets. Use 6mm² 3-core to export the earth and also to allow for the fact it is run in trunking. It will also give you a bit of capacity should you need to upgrade slightly at a later date.

Then at the shed fit an RCD with a 20A and 6A MCB. Alternatively, you can go with 2 RCBOs, works out a bit more expensive but it will minimise any inconvenience caused by an earth fault on one of the circuits.

 

[sealeon]

The tin roof is just supported on timber so wont go with the bonding I dont think.Thank you very much that your stars

 

[sealeon]

Sorry back again does the suplly to the shed have to have a double pole isolator inside the house 40 amp dp switch?