Garage wiring

[Westctony]

Hi all.
Quick question for any pro sparks - all the cabling in my garage (separate from house) is run through metal conduit. I need to move and replace the light fitting, sockets, and switches, and rather than cut and try to bend the metal conduit, I'd like to replace it all with plastic stuff.

Is this something I can do, or do I need a qualified spark to do it?

Thanks.

 

[Charlie_]

Seems a shame to do away with metal conduit.
How old is the installation?
Plastic is a lot easier tbf.

 

[Pete999]

GET A SPARKY IN MATE

 

[Westctony]

Seems a shame to do away with metal conduit.
How old is the installation?
Plastic is a lot easier tbf.

It's fairly old, has a board in the garage and it's own rcd from the house board. It is a shame to get rid of the metal, but need to move the light to get the headroom for my van, and it's simply easier to lose the existing metal and replace, than try to cut and bend to where I need it to go.
As I'm doing that, may as well replace a cracked socket and switch at the same time.

 

[littlespark]

Plastic is much easier to work with. Just need to be able to cut to length and use premade bends.
However, the cabling inside should be done by a spark.
To be fair, I haven’t a clue what your particular set of skills are.

 

[Westctony]

Plastic is much easier to work with. Just need to be able to cut to length and use premade bends.
However, the cabling inside should be done by a spark.
To be fair, I haven’t a clue what your particular set of skills are.

Used to do auto electrics as a hobby, and done plenty of socket/light replacements over the years, so not phased by doing the work. Not touching the board, or replacing the cabling, it's simply a case of removing the light/socket etc, sliding the old metal off, sliding on the new plastic and replacing the socket etc.
I'm not adding to the circuit, or cutting the wires, just replacing the conduit.
As I understand l it, I don't need the wiring to be in conduit, but as it's a garage I'd prefer it was.
Having taken a 240v shock as a young child, I fully appreciate what electricity can do!

 

[littlespark]

I agree it’s a shame to take out the metal pipe, but at least it can be recycled easily.

 

[Charlie_]

Plastic is much easier to work with. Just need to be able to cut to length and use premade bends.
However, the cabling inside should be done by a spark.
To be fair, I haven’t a clue what your particular set of skills are.

 

[westward10]

How are you sliding the new plastic on. I assume there are separate cpcs (earths) within the steel conduit.

 

[Westctony]

How are you sliding the new plastic on. I assume there are separate cpcs (earths) within the steel conduit.

I haven't had a real in depth check, but I can't see any separate cpcs. As far as I can tell it goes back to the consumer unit, and presumably back the the main one in the house. Whilst the house is pre 67, the wiring was obviously recently upgraded (as there's an earth wire), and looks like the previous owners simply ran the new cabling through the existing conduit.

 

[SparkyAndGeorge]

Have you done the grouping factor calculations for the conduit?

 

[Westctony]

Have you done the grouping factor calculations for the conduit?

I haven't, but it's 1 light and 2 switches, plus a single socket (separate conduit). Current metal is 20mm, was just going to replace with 20mm plastic.

 

[westward10]

You need to ensure there are separate cpcs in the existing system and that the steel conduit is not being employed as the cpc.

 

[Westctony]

You need to ensure there are separate cpcs in the existing system and that the steel conduit is not being employed as the cpc.

Had a check after you earlier comment - I can't see that the metal is anything other than what the wire runs through. I recently had a loft conversion done, and had full check done so I know everything is in order.

 

[littlespark]

Double check that @Westctony .
Having a loft conversion done, the electrician then would have just tested new or modified circuits, unless you specifically asked them to do the garage too.

Please don’t think we’re trying to put you off. The comments raised have been valid about grouping factors etc.
We get a lot of complete numptees on here asking for advice, and we wouldn’t forgive ourselves if we told them exactly what to do and they ended up burning their house down.

 

[Westctony]

Double check that @Westctony .
Having a loft conversion done, the electrician then would have just tested new or modified circuits, unless you specifically asked them to do the garage too.

Please don’t think we’re trying to put you off. The comments raised have been valid about grouping factors etc.
We get a lot of complete numptees on here asking for advice, and we wouldn’t forgive ourselves if we told them exactly what to do and they ended up burning their house down.

I understand. I know he checked the whole lot, as we needed a new unit in the house. If I start replacing it and find problems, I'll get someone in to do it.

 

[littlespark]

Sensible approach.

No need to mention safe isolation procedure, then?

 

[Westctony]

Sensible approach.

No need to mention safe isolation procedure, then?

Trust me, after taking a 240v shock aged 4 or 5, I'm a bit OCD with making sure circuits are dead (which isn't a bad thing). Both units switched off, and everything checked with a meter.

 

[Pete999]

How are you sliding the new plastic on. I assume there are separate cpcs (earths) within the steel conduit.

Trust me, after taking a 240v shock aged 4 or 5, I'm a bit OCD with making sure circuits are dead (which isn't a bad thing). Both units switched off, and everything checked with a meter.

What sort of meter ???

 

[TJ Anderson]

I haven't, but it's 1 light and 2 switches, plus a single socket (separate conduit). Current metal is 20mm, was just going to replace with 20mm plastic.

As you've got 2 circuits and 1 is powering 1 light, even if 1mm csa, it will be less than 30% percent of its grouped rating and therefore can be disregarded for the other cables in the group, of which there is one, which is the socket circuit. I really don't think grouping will be an issue. As already said, cpc is the main thing as the steel conduit may be the cpc....in which case a seperate cpc would need to be added for each circuit..

 

[Westctony]

What sort of meter ???

It's not multi meter - proper tester with probe. Used it a lot when doing auto stuff, and always when doing mains stuff.

 

[TJ Anderson]

It's not multi meter - proper tester with probe. Used it a lot when doing auto stuff, and always when doing mains stuff.

A multimeter would be fine too on the voltage setting.

 

[l4urence]

I would keep the metal conduit - if you need new bends made up I can probably help out - PM me. I'm based not far from Brighton.

 

[Charlie_]

What size is the old conduit?
Probably imperial?

 

[l4urence]

What size is the old conduit?
Probably imperial?

Imperial I'd wager - Lewden make some steel adapters for the thread size change.