Electrical questions

[somebody]

I am considering whether or not to get power installed to my garage, as it is a hassle running an extension lead from the house any time I want to do some work involving power tools. It would also mean that I can have LIGHT, and a wired security alarm in the garage too.

After reading this: http://www.ess.govt.nz/rules/pdf/ecp51v18.pdf to get an idea of legal requirements for home wiring, I have a few questions for those who are current/former/retired electricians. (A quote I got a few years back from an electrician was too expensive for what I can afford, which is why I'm considering doing as much of the work myself as I can legally do).

1) Is running a mains cable overhead between a house and a garage legal (assuming it is properly protected by conduit etc)? The code of practice only mentions underground cabling.

2) As all new wiring requires an RCD, will an RCD be required at BOTH the main switchboard, and the submain switchboard in the garage, or is just one needed? If just one, which switchboard does it need to be on?

Thanks in advance.

[godfather]

Just a thought you may need to have, you should get a sparky lined up first that is prepared to do a CoC as you may do all the work and find nobody prepared to sign it off at the end. There is no compulsion for a sparky to approve your work, its a matter of choice.

Without dragging out AS/NZS 3000 and checking, the RCD is most likely to be needed at the garage end, protecting the outlets.

Overhead is fine, but overhead in conduit is a new one on me?
How are you going to support it?
There will be minimum clearances above ground.

Neutral screened cable is commonly used for overhead, the same cable commonly used as underground in most cases (but hard drawn copper for overhead).

[somebody]

Thanks Godfather.

I may have to scour the internet for more reference material on laws surrounding overhead cabling, or face the fun task of digging a 600mm trench.

[pine-o-cleen]

How big is the gap between shed and house? I'd only do overhead if it was say 1 or 2 meters.

[pctek]

as it is a hassle running an extension lead from the house any time I want to do some work involving power tools. It would also mean that I can have LIGHT, and a wired security alarm in the garage too.
.

We have this arrangement.

We have a large outdoor extension permanently out there, plugged into a mulitbox. Multibox has a light connected to it too.

[somebody]

How big is the gap between shed and house? I'd only do overhead if it was say 1 or 2 meters.

Distance is about 6m, 500mm in from the fence line.

[somebody]

Another question is... would it be legal to run it in conduit along the fence (i.e saddle clipped to the fence railing)?

[plod]

a mates garage uses conduit over head the distance been about 4 meters. The conduit is supportered by wire, this was all done by a sparky so I presume it is legal, but we all know presumption is the mother of all ****ups