Laying cable over ground to garage

[Big Sixty]

Hello All,

I'm building a detached garage about 70' from the house and want to run power to it (for welders and air compressors).

However, my garden is full of trees, shrubs and bushes - there is no suitable route for a buried cable that won't severely disturb the roots (I have dug a number of pilot holes to check) and I don't want to injure my protected trees, not to mention that if I do lose a tree to the wind it will probably take the cable with it.

I'd like to run the cable overground. The routing would take it under a canopy of bushes - visible but not intrusive. The options I've thought of are:
1. - Run the cable through a steel conduit, mounted on posts set in concrete at about 18" above ground.
2. - Run the cable trhough a concrete cable trough (sealed off at both ends to prevent rodents getting in) at ground level (assuming they can be had in sensibly small sizes).
3. - Mount armoured cable to my (very substantial timber) deviding fence - though I understand that fences are considered a temporary structure.

I’m happy to do the routing hardware myself, but I’d rather find a professional electrician to do the electrical installation, hence me asking in the professional section.

Is there anything wrong with what I am proposing?
I am aware of a number of people who have had electricians refuse to install cable above ground because they said it was against the regulations, but I cannot find a british standard that actually states this?

Any and all help greatly appreciated.
Best regards,
Big Sixty

 

[Richard Burns]

No problem running the cable above ground, so long as the cable is suitable for the weather and for any likely mechanical damage it may suffer. I would choose 3 first, or a modification of 1 to have armoured cable run on a specific support structure near ground level.
You will find that the cost will be high to supply that sort of load over that distance.

 

[telectrix]

i'm with RB. option 3. keep the cost down and the cable is accessible to inspect for any damage. ( as long as the fence is your property, not next door's).

 

[Big Sixty]

Hi guys,

Thanks for the response, much appreciated.

The fence isn't mine, so perhaps armoured SWA clipped to a support structure is the best bet.

Richard - what do you mean regarding the cost? Installation cost or running cost?

Best regards,
Big Sixty

 

[telectrix]

installation cost, obviously. if the fence belongs to neighbour, permission could be obtained.

 

[Richard Burns]

The cable is going to need to be about 25mm² to supply welders and air compressors (assuming it is only one of each) and this is ~£10/m, over 30 m so a base level for just the cable of £300 just to start with.

 

[Guest77]

Well the answers in here are a suprise.

 

[Big Sixty]

Hi all,

Thanks for the responses, much appreciated.

I'm surprised at the gauge of the cable needing to be so large, I've run both the welder and the aircompressor on a 20m 13A RCD extension, though not at the same time.

So running a cable overground is fine if it's supported - now I just need to find an electrician who'll do it.

Cheers guys,
B60

 

[Guest77]

Hi all,

Thanks for the responses, much appreciated.

I'm surprised at the gauge of the cable needing to be so large, I've run both the welder and the aircompressor on a 20m 13A RCD extension, though not at the same time.

So running a cable overground is fine if it's supported - now I just need to find an electrician who'll do it.

Cheers guys,
B60

No problem there, plenty on here, myself excluded of course though

 

[Marvo]

If the fence is substantial in construction I'd probably saddle an SWA cable to it. In heavily forested areas which are private property we often use a class 10 HDPE pipe (irrigation type pipe) on the ground as a duct, it usually stops the porcupines from shredding off the outer PVC sheath so if you've got rodents running around it may be an option but it can be relatively easily stolen if it's accessible to the public.