Wiring Steel Garage

[GlennLogan]

Hi All,

I'm about to start wiring up my garage for powerpoint and fluro lights. I'll get an electrician to actually connect it. I have a powered switchboard and the garage is prewired to the board.

My question is, what are the regulations for fixing electrical cable to a steel garage? - it is a fairly standard garage, a 6x9m, "C" section main supports and colourbond cladding and concrete floor.

Does cable need to be placed in conduit or can I simply lay it in the horizontal steel channels that brace the structure? Once in the channels I could protect it by covering with plywood or MDF sheets.

Thanks in advance

Glenn

[spartan]

I have a similar arrangement in my shed. I have a separate run from my board to the workshop, all on a workshop fuse...

I am certainly know expert but I can give you the general rule of thumb..., at least until a more authorative voice appears..

This in itself poses an interesting point, you have stated that you want to lay cable for lights and power points....



Lights 1.0mm cable is the standard I believe, Powerpoints, 2.5mm

As far as conduit goes I believe that any fixed cable that is generally reachable must be covered/shielded. In the house this is generally done by plaster etc, in the shed it is a combination of conduit and flex, run in the horisontal and vertical channels, once it is above 2.4m it can generally by run within the channels of the structure so long as it is secured.

The important point is that all terminations, joins, connections must be appropriately shielded and insulated.

Hope this is of some help.

[soundman]

Firtsly the frame of the shed should be bonded to the earth.
Re the wiring
Providing that all sharp edges are " treated" there is nothing realy specific about wiring metal structures. All the regs about securing & protecting cables remain the same. However a lot of the time it's just simpler to conduit on a steel structure.

The two main concerns are sharp edges and earthing the structure.

speak to your sparky or check as3000.
cheers

[gatiep]

In my steel shed all the cables are in conduit.....its neat, safe and out of the way.

[Kev Y.]

When I did my shed (which I no longer own :mad: ), I placed the wiring in the "top hat" type rails around the sides of the structure, then I cut up pieces of left over wall cladding, and screwed this over the rails, hiding the wiring from view and fingers.

This also gave me somewhere to screw the power points to.

Also have you thought of just putting power points in your ceiling and pulgging your fluro's into them?, I did this and it gave me a few extra overhead power points, can in handy at times. Also allowed me to relocate the lighting as was needed

[Jacksin]

I would say it depends on your state regulations. Here in SA, when I had my shed wired the sparky told me it really should all be conduited incase it is ever lined (more protection for the cables should they be hit when screwing the linings back, I suppose).

As I never intended to line my shed he didnt bother with conduit. Where cables went through 'C' sections he drilled a larger hole and used a short piece of flexible conduit as a protecting sleeve.
Jack

[GlennLogan]

... I placed the wiring in the "top hat" type rails around the sides of the structure, then I cut up pieces of left over wall cladding, and screwed this over the rails, hiding the wiring from view and fingers.

Hi, yes this sounds pretty much what I'd planned top do - run the cables and cover them - provides safety and a place to mount the power points & switches .

Also have you thought of just putting power points in your ceiling and pulgging your fluro's into them?

Yes, I had also planned this - I've picked up a number of switchless points which I'll mount to the sections on the roof. Sounds like we are on the same wavelength!

Thanks to everyone who has responded.

Glenn

[Barry_White]

It is much better to run in conduit and use flexible to get around difficult bends. Most electricians today use 1.5mm cable for lighting circuits as the cost is minimal in difference to 1mm cable.

If you run it all in conduit you can just use building wire rather than thermoplastic twin and earth and it is easier to run it in the conduit and it saves buying twin and earth as well as twin to run as switch wires. Building wire is cheap as.

I dont know about Clipsal but HPM make a flat mounting plate to attach power point mounting blocks to. This closes in the back of the mounting block so that you dont have to attach an earth wire to the steel frame at each power point.

If you are going to use switchless points to plug your lights into and wire it in 1mm or 1.5mm wire you will have use points with round earth pins so you cant plug tools etc. into them and put plugs with round earth pins on to the leads on the lights.

It would probably be better to wire your light points in 2.5mm cable and then you would be able to plug power tools into them.

[soundman]

For connections in a lighting circuit round eart pin is not necessary if the point is over a certain height. check as300 I think its 3m.

For power connection some pendant outlets just above head height are just great.

Clipsal do do a mounting block with a back i it designed for use with conduit. They are much more solid then the standard patern (449) block.
I had a quantity of metal plates cut that span the top hat section to mount my outlets & stuff on.

Some smart electricains are using heavier cable these days as it makes compliance with fault loop impedance requirement easier.
in the past 1mm2 for lights and 1.5mm2 for power was very cool. but now if you wire a 30m circuit on a 20 amp breaker in 1.5mm2 you will not be compliant.
So 1.5mm2 for light and 4mm2 for power is very cool. In some instalations the old sizes will get in the specs. but hey times change.

I agree wth the rigid & flexy method, run rigid where you can & use short lengths of corigated to go round weirdo corners. very sweet.

I ran building wire for the lights because I could get more circuits in the conduit. but I used TPS for the power circuits.

cheers