Outdoor shed cable, trench depth?

Stinicker

I have some outdoor sheds with no electricity, I am thinking of getting an electrician to do the wiring but want to do some work myself to cut costs. I am thinking of hiring a mini digger and digging the trenches to the outhouses but am not sure of the depth for cable, I know it has to go in a red pipe and yellow tape be put over it.

I was thinking of sinking it well down to about 1.5m to 2 metres? Is this madness and I can't find the minimum depth for Health and Safety reasons.

Once I had the the trenches dug I could let the sparky to run the cable and do the rest and I'd fill it in by hand afterwards.

The cable run is short at about 30 metres from house to outhouse.

M cebee

600 minimum i think

deeper if necessary

enmac

300mm is fine in a domestic situation especially if you use the 50mm ESB ducting.

no need to backfill by hand - dig the trench , install the ducting , backfill using the digger - the sparks can fish the cable through the installed duct.

Davy

600mm down to the duct, and the marker tape/boards 300mm above this

Stinicker

Davy wrote: »

600mm down to the duct, and the marker tape/boards 300mm above this

Is it good practice to laydown plywood or some other material over the 300mm soil that I would place over the pipe?

We looked at the job this evening and I was thinking about an overhead wire system with 3x1.5 NYM-J cable suspended from a wire but I think it is safer and more durable to go the underground option instead even if more expensive.

As you can see from my schematic, I have four outhouses to run power to, my plan is to put lights inside all the outhouses and a single socket in Outhouse 1 and 2 which are joined toghether, 3 & 4 will be lights only.

I also plan to install a few flood lights with the back yard getting two floodlights from either side for maximum illumination and the floodlight from Outhouse number three to be controlled from the house thus requiring a second cable.

The floodlight from Outhouse 2 can be switched from there and the two from the dwelling house can can be controlled from there. I won't go for sensor lights as they are not needed and would be triggered off by cats or dogs costing me a fortune in power as the dwelling is not occupied and is an old farmhouse.

handydandy

Stay underground with the cables, it will be a much neater job in the long run. I have seen plenty of suspended cables and they tend to become eye sores. When your digging the trenches just think of it as a long term job.

Lay the pipes and put some rope inside if you intend to back fill before cables are installed then who ever runs the cables can attach on to the rope, just make sure the ropes are 100%.

M cebee

you may not need an extra cable for a light controlled from the house

you could also consider one supply for sheds 1,2 and 3

put in decent supplies anyhow if you're going to the bother of ducting etc.

twitch1984

Stinicker wrote: »

Is it good practice to laydown plywood or some other material over the 300mm soil that I would place over the pipe?

We looked at the job this evening and I was thinking about an overhead wire system with 3x1.5 NYM-J cable suspended from a wire but I think it is safer and more durable to go the underground option instead even if more expensive.

As you can see from my schematic, I have four outhouses to run power to, my plan is to put lights inside all the outhouses and a single socket in Outhouse 1 and 2 which are joined toghether, 3 & 4 will be lights only.

I also plan to install a few flood lights with the back yard getting two floodlights from either side for maximum illumination and the floodlight from Outhouse number three to be controlled from the house thus requiring a second cable.

The floodlight from Outhouse 2 can be switched from there and the two from the dwelling house can can be controlled from there. I won't go for sensor lights as they are not needed and would be triggered off by cats or dogs costing me a fortune in power as the dwelling is not occupied and is an old farmhouse.

3x1.5 is fine for lights but you will need 2.5 for any sockets

Bruthal

Underground is the only way to go there, overhead nymj out to sockets and lights in various sheds would be a right mess

I would of thought it ok without boards and marker tape myself, thats fine for miles of cables laid by the esb with 300 amp fuses etc out in the street, but for a back garden with a 3x10 swa i would of thought a foot down inside piping is adequate, and with swa it can be buried straight in the ground cant it, although ducting is a lot better obviously for pulling in cable later . I cant see anyone putting boards and markers for their garden shed down the back of the garden. If its an open farm yard thats liable to be dug up by mechanical diggers in the future then maybe. Is that the case here?

M cebee

twitch1984 wrote: »

3x1.5 is fine for lights but you will need 2.5 for any sockets

those sizes are ok for a final circuit in a house

he should be using 4-6 minimum here

mac2006

New to site so go easy

Doing a similar job as above ,need power supply for sockets and lights in shed .I had planed to take supply from exiting esb meter box on side of house instead of fuse box inside house.need to know is it possible to connect a second supply to esb meter to go to a fuse box in the shed.

Bruthal

mac2006 wrote: »

New to site so go easy

Doing a similar job as above ,need power supply for sockets and lights in shed .I had planed to take supply from exiting esb meter box on side of house instead of fuse box inside house.need to know is it possible to connect a second supply to esb meter to go to a fuse box in the shed.

You will have to bring the supply from your MCB/fuseboard in your house. Any new supplies from the meter position involve new meters etc.

What was your idea taking from meter position? Looks easier to get to maybe? Anyway the MCB board in house is where you will have to connect to, and then have a small MCB board in the shed.

mac2006

i was hoping to avoid rooting cable throught house as it finished,also i will be welding in shed and thought taking power from meter directly would give a more stable supply.i allready have ducting buried under garden to shed so it would just be a matter of fishing the cable up the cavity into meter box and conecting to the meter outlet leaving all on the one meter and one bill,

Bruthal

mac2006 wrote: »

i was hoping to avoid rooting cable throught house as it finished,also i will be welding in shed and thought taking power from meter directly would give a more stable supply.i allready have ducting buried under garden to shed so it would just be a matter of fishing the cable up the cavity into meter box and conecting to the meter outlet leaving all on the one meter and one bill,

Well it would involve another meter and im not sure about getting a second meter for a shed, you will get a supply adequate from your MCB board for that no problem as long as the wiring in the house is up to date, is the board in a completely different location than the meter, a lot of times they are just on the inside of the same wall, but could be anywhere of course.

mac2006

i got on to esb networks about problem .they told me it can be done but i have to get them to make the conection at the meter cost around 150,would i have to get the wirering to the shed certifed or could i do it my self

Bruthal

mac2006 wrote: »

i got on to esb networks about problem .they told me it can be done but i have to get them to make the conection at the meter cost around 150,would i have to get the wirering to the shed certifed or could i do it my self

Usually would have to get it certified for a meter connection, i thought they would put in a second meter myself, but it does seem a lot of hassle just to avoid going to the house board. Where is the board compared to the meter?

Stinicker

robbie7730 wrote: »

Usually would have to get it certified for a meter connection, i thought they would put in a second meter myself, but it does seem a lot of hassle just to avoid going to the house board. Where is the board compared to the meter?

Would having a 2nd meter lead to having second ground rental charges also?

Bruthal

Stinicker wrote: »

Would having a 2nd meter lead to having second ground rental charges also?

Im not sure about that one, usually another meter does mean more standing charges, im not sure if they would connect a second supply from the same meter you have already, id say your looking at a second meter if thats the way your going to go, maybe with the same service cable there will be just the one standing charge, i dont know what their policies are these days. Others on here would know that one.

M cebee

they may fit a 2nd meter -it's been done for granny flats etc. -hardly a great idea here


there'd be a 2nd standing charge i'm sure



new sub-main to shed is the way to go

Bruthal

M cebee wrote: »

they may fit a 2nd meter -it's been done for granny flats etc. -hardly a great idea here


there'd be a 2nd standing charge i'm sure



new sub-main to shed is the way to go

Yes seems a big waste of effort really, cant be that difficult to go to house board.

mac2006

the house is a simi d ,the fuse box is on the joining solid wall,to the left the front door and to the right is the stairs, above is a box room .i cant run the wire through the floor joists as they stop at the stairs ,i cant chase the walls, run the wire and then replaster or i will end up having to live in the shed . so the only option is to take it from the meter which is on the opiset gable to the fuse box .I am going to use armored cable to be safe but what size wil i need to run 4 double 13A sockets,1 16A socket for welding and 2 lights .cable has to cover 25 meters

M cebee

you won't be able to branch off the existing meter assuming the main ocpd
is located in the consumer unit-that's not allowed

dunno is there a specific rule on branches with the new setup-main ocpd in the cabinet

-wouldn't be standard practice anyhow-new submain from consumer unit is usual method


dunno would you get a second meter-if you did you'd need a main ocpd in cabinet and prob a standing charge