Can I place SWA cable here?

[veedee]

I would like some garden lighting

1. Is it best to run the SWA cable directly from the consumer unit?

2. Is it okay to lay the SWA cable in the chase pic 1? The depth of the chase is between 175-300mm

The chase is filled with a membrane and 20mm gravel

The SWA cable would then run along side a plastic pipe (depth 300-450mm) which would be connected to a soakaway crate (depth 800mm)

The soakaway/ SWA cable will be filled with gravel, sand and soil

Is there anything wrong with the above? If so, what can I do to get around this?

 

[ericmark]

1. Is it best to run the SWA cable directly from the consumer unit?

The problem is the Part P law, an electrician would likely take it from the consumer unit, however as a DIY person it costs too much to register the work when forming a new circuit, so only in Wales would you come direct from the CU as in Wales any work outside is notifiable so makes no difference.

Work in the garden is not as easy as it seems, the problem is earthing, so it depends what the SWA feeds, in the main a out door socket is in a plastic box, and is plastic, and the items plugged into it are class II, i.e. don't need an earth, so there is no real problem. When powering a wooden shed again no real problem, but powering a tin shed there is a problem, same as powering a caravan made of metal.

In fact in the UK the ESQCR prohibit the use of a TN-C-S system for the supply to a caravan or similar construction. So you should not power a tin shed using a PME supply.

I am sure we have all bent or broke the rules from time to time, and loss of PEN it seems around 300 cases a year, of which 10% cause injury, so it is a low risk, but it is a risk, and so would be wrong not to tell you.

 

[veedee]

In pic 1, the depth of the chase is 175-300mm. Can I place the swa cable here? The chase is filled with 20mm gravel.

Generally is it okay to place gravel on top of swa cable then back fill? Or will this damage the cable.

And I plan to use one cable for outside lighting like a floodlight and one outdoor plastic socket.

 

[bernardgreen]

Generally is it okay to place gravel on top of swa cable then back fill? Or will this damage the cable.

Gravel with sharp points can damage the outer sheath of the SWA which will then allow moisture to reach and corrode the steel strands of the armour

 

[veedee]

Gravel with sharp points can damage the outer sheath of the SWA which will then allow moisture to reach and corrode the steel strands of the armour

So is there a way around this? For example, is it acceptable to duct the cable with something like solvent weld plastic pipe. Then place the gravel on top?

 

[bernardgreen]

Ducting is the best option, with a marker tape above the ducting

 

[JohnW2]

So is there a way around this? For example, is it acceptable to duct the cable with something like solvent weld plastic pipe. Then place the gravel on top?

You could do that. Alternatively, if you are concerned about the possibility of gravel damaging the cable, you could use sand immediately around the cable, and then the gravel.

Kind Regards, John

 

[veedee]

Thanks guys