Running power to an outside building

[mark-s]

I'm currently renovating a house and the next job is to send power out to what will be a small dog grooming salon.

At the moment we live in rented property, the salon is run off a length of 2.5 twin and earth running off a socket in the kitchen, this goes to a fusebox in the salon. I know this isn't ideal but was a temporary solution because it was rented. In the 4 years it's been set up surprisingly its never tripped once, even with all the damp in the building due to dogs being washed and dried!

The new set up will be done properly as its going to be a permanent fixture in a house we own. The salon will be about 25 meters from the house, cables will be run in 4in waste pipe laid at a depth of about 1m. Due to the solid structure of the 4in pipe, do I need to use armoured cable or would 10mm 3 core be ok. At no point from the house to the salon would the cable not be in the 4in pipe. This time the cable will be connected to the house fuse box and not off the back of a socket!

Any advice would be appreciated.

 

[Tigercubrider]

I am not qualified but would expect that it needs to be armoured and laid with hazard tape above the run?
Someone could dig with a digger or such and take out the plastic pipe and un armoured cable.

1M is a bit deep (0.5 minimum) as digging a narrow 1M trench is hard without making it very wide.

The armour is the earth.

 

[SUNRAY]

I'm currently renovating a house and the next job is to send power out to what will be a small dog grooming salon.

At the moment we live in rented property, the salon is run off a length of 2.5 twin and earth running off a socket in the kitchen, this goes to a fusebox in the salon. I know this isn't ideal but was a temporary solution because it was rented. In the 4 years it's been set up surprisingly its never tripped once, even with all the damp in the building due to dogs being washed and dried!

The new set up will be done properly as its going to be a permanent fixture in a house we own. The salon will be about 25 meters from the house, cables will be run in 4in waste pipe laid at a depth of about 1m. Due to the solid structure of the 4in pipe, do I need to use armoured cable or would 10mm 3 core be ok. At no point from the house to the salon would the cable not be in the 4in pipe. This time the cable will be connected to the house fuse box and not off the back of a socket!

Any advice would be appreciated.

What information has been put on your planning application?
Your electrician will be the correct person to ask.

 

[SUNRAY]

I am not qualified but would expect that it needs to be armoured and laid with hazard tape above the run?
Someone could dig with a digger or such and take out the plastic pipe and un armoured cable.

1M is a bit deep (0.5 minimum) as digging a narrow 1M trench is hard without making it very wide.

The armour is the earth.

The armour is very likely not going to be used at the outbuilding.

 

[Murdochcat]

I am not qualified but would expect that it needs to be armoured and laid with hazard tape above the run?
Someone could dig with a digger or such and take out the plastic pipe and un armoured cable.

1M is a bit deep (0.5 minimum) as digging a narrow 1M trench is hard without making it very wide.

The armour is the earth.

Questionable advice …..

 

[flameport]

cables will be run in 4in waste pipe

Do NOT install cables in waste pipes.

Use cable ducting, so it can be identified as cables if it's dug up in the future.

 

[SUNRAY]

Do NOT install cables in waste pipes.

Use cable ducting, so it can be identified as cables if it's dug up in the future.

I assume it's planned to be in black pipe, only distinguishable from black ducting if the joins are found. The yellow warning tape is a good giveaway though.

 

[mark-s]

Yes its black pipe and i can use plenty of yellow warning tape.

Forgetting the legal, healthy and safety etc side of things and from what I've read, using normal cable instead of armoured would have no difference on the performance side of things its purely just that the armoured gives the cable protection?

 

[EFLImpudence]

Non-armoured cable will probably require RCD protection which might be inconvenient.

 

[mark-s]

There is a basic fusebox in the salon with RCD's so would be connected to that plus I'll get an electrician to connect the cable to the house fusebox where an rcd could be fitted. I suppose this is how its connected now, its just done via connecting to the house socket ring rather than directly to the fusebox.

 

[bernardgreen]

Forgetting the legal, healthy and safety etc side of things

Not sensible

using normal cable instead of armoured would have no difference on the performance side of things

normal cable is PVC which can degrade when below ground and damp. SWA uses XPLE insulation which does not degrade as fast as PVC does

 

[EFLImpudence]

There is a basic fusebox in the salon with RCD's so would be connected to that plus I'll get an electrician to connect the cable to the house fusebox where an rcd could be fitted. I suppose this is how its connected now, its just done via connecting to the house socket ring rather than directly to the fusebox.

Yes but the point is you do not want the cable to the salon controlled by a RCD in the house.

This is why you should talk to - or leave it to - your electrician as we cannot tell you everything.

 

[ebee]

Well the idea of putting it in a pipe rather than just laying in the ground has some merit in theory but whether you do or not you should be aware it will almost certainly allow water in on a permanent basis .
Black is the colour if you do.
marking tape above by a good spade length (or cable bricks as a warning is a must too.
One metre depth is good if you can achieve it but a bit shallower is usual.
Finally, SWA has many benefits and you can always use the armour and a core or two as earth connection too, which would bring the effective R2 value down.

 

[Taylortwocities]

There is a basic fusebox in the salon with RCD's so would be connected to that

I doubt that is true.
I think you might have terms confused, In the salon there might be MCBs, or one RCD and several MCBs or several RCBOs.
Please clarify, or post a photo of said device.

 

[ericmark]

1) You do not want rest of house to trip if a fault with salon so at house the RCD or RCBO will need to only supply the salon.
2) If the RCD or RCBO is fitted in the house, it will be a long walk to reset should the salon trip it.
With consideration of the above, better if the cable from house to salon does not need RCD protection, so any RCD or RCBO is in the salon, so that means SWA cable so the RCD or RCBO can be located in the salon.

Next is earthing arrangement. Is the house TN or TT? and will the salon be TN or TT? the answer to the latter is really down to what the salon is made from, is it metal or a non conducting material?

This is a little dated now, but should give you an idea of supplies to out building since it was published in 2005 the requirements for RCD protection and also the Part P building regulations have changed, but it is a good starting point.

The other consideration is future changes, where any EV car will be parked for charging, and hot tubs, etc. It may be due to future plans that a TT earthing system is better.

At the turn of the century we would not really consider earthing arrangements, surge protection, EV charging, or what the outbuilding was made of, or the problems with tripping RCD's and if type AC or A should be fitted, the trade has realised some early errors, including having only two RCD's for whole of house, today we lean towards all RCBO and type A, and with TT likely need to be double pole switching.

You need to get an electrician on board before you do anything, and see what can be done, including what underground services there are, and if putting in earth rods is going to cause problems, even maybe include the earth rods in the salons foundations. And this is not some thing that can be sorted on a forum.