wiring garage in 20mm conduit - choosing singles?

[Space cat]

-- maybe garages are more susceptible to fire or fumes than living spaces.

I'm sure that's true. When we had a bedroom extension built above our garage, the ceiling had to have a minimum resistance to fire and so did the door from the back into the house. That made perfect sense when you consider that a garage is likely to contain many flammable materials, including a car with a tank full of petrol!

What's more, the walls of our garage are bare brick so channelled wiring was, if not impossible, at least impractical. Horizontal channels in the walls would weaken the structure and putting them in the ceiling would mean breaching the fireproofing that's up there. Surface mounting with conduit was the obvious choice.

PS: Just for you BAS, no smileys today.

 

[ban-all-sheds]

Horizontal channels in the walls would weaken the structure

A generic concern.

and putting them in the ceiling would mean breaching the fireproofing that's up there.

You can use firestopping where services penetrate.

Surface mounting with conduit was the obvious choice.

It may well be the most practical solution, but I'm concerned about someone who thinks it is the only solution.

 

[GCarnegi]

I'm sure there are other, neater solutions which I could have used T&E for, but when the plans say it has to be surface mounted, and the building control guys (when queried by telephone) sinsisted on NO wiring being inside ANY walls of the garage, including the wall between the garasge and the utility room (can't even have flush sockets on the other (utility room) side of that wall for some reason), then surface running of wires is the only conclusion we came to.

On top of that, one of the side walls is bare granite blocks.

I guess we could have simply stapled T&E to the walls, but for mechanical protection I prefer to have the wires run inside conduit.

Apparently, the reason for not having wires inside the garage>utility room wall is because the insulation is combustible (unlike the 6x2 joists that make up the wall Mr Building Inspector?). In fact, the statement on the plans was no "services" so the restriction doesn't just stop at wires. (When pressed, the BCO did say I could run copper pipes, but no plastic).

Yes, the BCO may be misinformed, or misguided, but I'd rather keep them on my side than start spouting legislation at them and get their back up.

 

[riveralt]

Apparently, the reason for not having wires inside the garage>utility room wall is because the insulation is combustible (unlike the 6x2 joists that make up the wall Mr Building Inspector?). In fact, the statement on the plans was no "services" so the restriction doesn't just stop at wires. (When pressed, the BCO did say I could run copper pipes, but no plastic).

That's a load of rubbish - modern insulation is not combustible - also electric cables can quite happily be fitted in or be completely covered by insulation - provided their current carrying capacity is reduced accordingly.

 

[GCarnegi]

The cable insulation is pvc which is combustible .

 

[ban-all-sheds]

Yes, the BCO may be misinformed, or misguided

Or so shamefully ignorant and incompetent that they deserve the sack.

 

[sparkwright]

What colour would you make the switch wire of a 2-switch setup, when wiring singles in conduit? Yellow, red? Is there a regulation for that in the new colours?

You should use the brown, black and grey plus sleeved earth for a 2way switch setup.
You should use brown sleeving on the black and grey where appropriate.

What's wrong with just single browns for the 2 way switch wiring?

 

[RF Lighting]

Nothing. That's what I'd use.

 

[Space cat]

What's wrong with just single browns for the 2 way switch wiring?

Of the three wires required, I would reserve brown for the permanent live. Whether or not the other two need to be different is a moot point but, with the modern scheme for two-way wiring, it's helpful to be able to identify the ends without resorting to continuity tests.

 

[ban-all-sheds]

Free Dragon's Den Idea #4:

Singles with letter/number IDs printed on the insulation.

 

[GCarnegi]

I was thinking something similar yesterday. a device with a printing wheel / roller on it that prints text on a cable /wire as gets pulled off the reel.

 

[RF Lighting]