The Wall I Will be Painting

Plastering over electrical wires, Can you do it?

So I’m guessing you’ve just had some electrical work done and you have some new wiring chased into your walls. The electrical work has been done but the finishing is up to you, and you’re wondering whether you can just plaster straight on top or do you need to do anything special? Well, let’s have a look together!

Can you plaster over electrical wires?

The short answer is yes you can. But there are a few reasons why you might want to add some plastic capping first. This is true as long as you have an RCD protecting the circuit in question.

There is nothing strictly wrong with just plastering straight over the wires, so if this is what you are planning to do then go ahead. The PVC cable around the electrical cable will protect it and it will not have any sort of reaction to the plaster. If it is nicked or cut anywhere and you don’t realise then this could obviously cause issues.

What Else Can You Do?

Plastic capping would be the most common thing to do here.

Plastic Capping
Plastic Capping

This is simply a thin piece of plastic that goes on top of the cables. It offers protection against accidentally catching the cables with your plastering trowel.

It also makes it easier to pull the cables out if you ever need to at a later stage.

This is not a huge amount of protection though so a stray nail or screw will obviously still go straight through it, this method isn’t going to protect against that particular mishap.

Steel Capping

The same idea as plastic capping but this time made from thin steel. This offers more protection than the plastic capping but it is not foolproof. This is thin metal so can still be penetrated by a stray nail or screw, although this will be harder to do than with the plastic capping.

there are a few drawbacks to using metal capping, however. The first is cost, this stuff is quite a bit more expensive than plastic capping.

The next issue is with using metal on top of the electrical cable. If something drastic was to go wrong then the whole capping could become live, this is probably why it is a good idea to bond the metal to earth.

Steel Capping
Steel Capping

Conduit

You could also use conduit, of either the plastic or metal variety. The advantage here is when it comes to replacing the cables. It is a lot easier to pull out an old cable through a conduit and then push a new one through. Making a rewire much easier, most people don’t do DIY jobs with the idea of a rewire being done down the line though.

It would also be a lot harder to nail or drill through steel conduit than it would through steel capping. This is because of the round surface of the conduit. if you have ever tried to drill into a round metal you will know how difficult it can be. The screw, nail or even drill would be deflected down the sides rather than going through.

Why Cap At All

The main thinking about capping the cables with plastic is to protect the cables from the plasters trowel. These trowels are sharp and can easily nick the cable.

This is more of a problem if the cable is above the rest of the wall, so for instance if the cable is not chased in and you are having the full wall replastered. If this is the case then the plasterer would definitely appreciate some capping, you are making the job a lot safer for them.

If however, the cables are chased into the wall and you are just patching over the top then the risk of catching the cables should be near zero.

Daniel Berry

Hey, I'm Dan, I studied computer science with artificial intelligence at Loughborough University. I try to bring my tech knowledge to the posts where it is needed while also offering a DIY view to go with Sam's professional view on tools. I am a very keen DIY'er and have experience of doing everything the completely wrong way.

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