Charger cable depth

[Vadervonham]

Just getting quote for a charger being fitted. Going with the Andersen A2 as it is going to be on show on the drive.

I have sent a company the route for the cable to run around the edge of a small patio. The cable can easily be “hidden” / buried to then appear under the charger on an outside wall. Internally would make no sense as it would have to go through the rooms to get to the outside wall. The company asked if I want to dig out the channel to cut down on costs and time, which I am happy to do. However today when I asked about the depth of the channel I was firstly told 1m! Later told 450mm? I tried to check on regs but appears this only applies to public areas? Obviously the cable will be armoured and the route of the cable isn’t any place where any digging would occur.

I can easily do most of the route down to a reasonable depth but there is a section (about a metre) where it would only be about 100mm without having to dig up some stone steps.

Sorry this started off as a simple question - how deep does the electrical cable to the charger need to be buried?

Many thanks

 

[Mr Miserable]

You need to put out the bat signal for @arg @Jeremy Harris

 

[Adopado]

You need to put out the bat signal for @arg @Jeremy Harris

... and you can bet the reply will not just be a given number of millimetres!

 

[Vadervonham]

Thanks Mr M

 

[Adopado]

You need to put out the bat signal for @arg @Jeremy Harris

I think Jeremy must be on his hols. He's not posted on here for a couple of weeks ... cooee JH .. are you OK?

 

[Roy W.]

If you really enjoy digging then five metres is a nice round number...

 

[Roy W.]

I think Jeremy must be on his hols. He's not posted on here for a couple of weeks ... cooee JH .. are you OK?

Yes, I’d noticed his absence as well.

 

[Vadervonham]

Thanks Roy

 

[Roy W.]

Thanks Roy

I’m sure @arg will pop along shortly to offer some slightly more sensible advice.

The armoured cable to our garage (built in 2015) goes through a green plastic pipe, and is buried about 30-40cm down.

The photo below doesn’t really show the depth very well, but as well as filling in the trench there is also a good 30cm of hardcore and stones on top. The trench was extended along the side of the conservatory later in the project.

 

[Adopado]

Sorry this started off as a simple question - how deep does the electrical cable to the charger need to be buried?

After a brief scan over an electricians' forum it seems there are multiple views (who would have thought ). Whatever the decision will be it will have to suit the electrician you are using ... because they will have to certificate the work. I'm thinking that though you may get some very good advice on here it's still going to need the OK of the electrician you ultimately choose to do the installation.

 

[EV_Hopeful]

I am very definitely not an electrical installer, so can't comment authoritatively on the regs.

We had ours installed a few weeks ago and it crosses our front garden. Installers told us that it should be an armoured cable at a depth of 50 cm and a yellow warning strip laid just above it (though still buried.) As an aside, the cable had to cross under our footpath and I had assumed that they would be pulling up paving stones and then relaying them. (With likely damage). In the end they just used a really long drill bit to drill out a narrow tunnel underneath the slabs. Maybe the installers could do that after you have dug the rest of the channel?

 

[Vadervonham]

Thanks to all, will do the dig and do my best effort at the bottom of the stairs and send picture to electrician. If need to lift the flags I will but at least now I’ve got some idea that 450 mm is about right. And yes ultimately it is down to the electrician signing it off.

Here is the offending flags!

Red line is cable route.

So glad it’s not 1m deep!

 

[arg]

There is not a fixed minimum depth. The regulations just say:

Buried cables, conduits and ducts shall be at a sufficient depth to avoid being damaged by any reasonably foreseeable disturbance of the ground.

The regulations also explicitly require the marker tape (or tiles, but those wouldn't normally be used for a job like this).

So the depth is a matter of judgement by whoever is signing off the work. Under a lawn, it's got to be safe against someone aerating the turf with a fork, or pegs if someone decides to put up a tent. Under a flowerbed might be deeper, especially if there's any risk someone might turn it into a veg patch and start digging potatoes in there. Under a patio you might argue for less, but then there's the problem of what happens when it exits from under the patio - if that's under a flowerbed or lawn, the cable has got to have dived down to a suitable depth before coming out from under the protection of the patio. The warning tape also implies a certain depth - to be meaningful, it's got to be sufficiently above the cable that you get a chance to find the tape and stop digging, rather than tape and cable coming up in the same spadeful.

600mm is a commonly quoted conservative depth for general domestic conditions.

Not directly relevant, but UKPN's standards for their work are:

• Footways, grass verges or private property = 450mm;
• Carriageways (including road crossings) = 600mm;
• Normal agricultural land (not subject to deep ploughing) = 1050mm;
• Agricultural land subject to deep ploughing = 1200mm.

For the OP's question about what to do where there is only 100mm before hitting something else, I'd be thinking that's effectively within a structure rather than simply buried in soil, and I'd be thinking of putting that section in a duct.

 

[Vadervonham]

There is not a fixed minimum depth. The regulations just say:

Buried cables, conduits and ducts shall be at a sufficient depth to avoid being damaged by any reasonably foreseeable disturbance of the ground.

The regulations also explicitly require the marker tape (or tiles, but those wouldn't normally be used for a job like this).

So the depth is a matter of judgement by whoever is signing off the work. Under a lawn, it's got to be safe against someone aerating the turf with a fork, or pegs if someone decides to put up a tent. Under a flowerbed might be deeper, especially if there's any risk someone might turn it into a veg patch and start digging potatoes in there. Under a patio you might argue for less, but then there's the problem of what happens when it exits from under the patio - if that's under a flowerbed or lawn, the cable has got to have dived down to a suitable depth before coming out from under the protection of the patio. The warning tape also implies a certain depth - to be meaningful, it's got to be sufficiently above the cable that you get a chance to find the tape and stop digging, rather than tape and cable coming up in the same spadeful.

600mm is a commonly quoted conservative depth for general domestic conditions.

Not directly relevant, but UKPN's standards for their work are:

• Footways, grass verges or private property = 450mm;
• Carriageways (including road crossings) = 600mm;
• Normal agricultural land (not subject to deep ploughing) = 1050mm;
• Agricultural land subject to deep ploughing = 1200mm.

For the OP's question about what to do where there is only 100mm before hitting something else, I'd be thinking that's effectively within a structure rather than simply buried in soil, and I'd be thinking of putting that section in a duct.

Arg, thanks will be able to get 450 mostly and look at ducting for the bottom of the stairs.

thanks again

Ps still no hidden vin so probably plenty of time to dig.

 

[Keeper]

Arg, thanks will be able to get 450 mostly and look at ducting for the bottom of the stairs.

thanks again

Ps still no hidden vin so probably plenty of time to dig.

I’d be more worried about the other cable (vertical white) to the external power socket. That doesn’t look like armoured cable and looks a bit vulnerable.

 

[Vadervonham]

I’d be more worried about the other cable (vertical white) to the external power socket. That doesn’t look like armoured cable and looks a bit vulnerable.

Good spot!

That’s a redundant fuse box for septic tank.

 

[Adopado]

I’d be more worried about the other cable (vertical white) to the external power socket. That doesn’t look like armoured cable and looks a bit vulnerable.

My professionally installed charge point is connected with twin and earth inside a section of flexible plastic trunking! It's only a couple of meters and run along a wall above ground level ... however, not very inspiring.