Rules for AC power cable to Obs?

glend (Glen) · #1 03-02-2015, 10:29 AM

Does anyone know what the regulations are (in NSW) for underground AC power runs to an observatory? I want to extend my shed power to the Obs, only about ten metres in total. I only need a single 10amp circuit. This is private AC off my inverter/battery bank which is solar charged - so not grid connected. What is ok? Is 300mm deep enough and do I need special conduit and a coverboard, or tape above it? Thanks

killswitch (Edison) · #2 03-02-2015, 12:45 PM

I'm no electrician but i believe the min depth is now 600mm for mains type cable. You could probably get away with less for a backyard where theres not much activity on the surface.

You need to use heavy duty electrical conduit (Orange) like this:

http://www.bunnings.com.au/deta-25mm...nduit_p4330851

Place a yellow plastic sheet or even tiles on top of the conduit as a warning in case someone tries to dig it up by accident. Updating the house plans is also a good idea.

For a 10m/10a run, i would expect a 4mm electrical cable to be used but thats really up to an electrician to recommend.

Buy the parts and do the labour but get a certified electrician to hook it all up and check its all safe.

If you also plan to run data in the future, that needs to be on a separate conduit.

mswhin63 (Malcolm) · #3 03-02-2015, 12:51 PM

Should be able to glean some information from this http://www.commsalliance.com.au/__da...S009_2006r.pdf

tlgerdes (Trevor) · #4 03-02-2015, 05:28 PM

According to that doc 300mm. Also put it on its own ELCB at your house. That way if someone does dig it up, it only trips out the obs and not the whole house.

glend (Glen) · #5 03-02-2015, 07:13 PM

Thanks guys. The shed supply that will feed it already has an ELCB. Certainly glad I don't have to go down to 600mm - I've had enough digging after the footings and roof support posts, and the pier.

mswhin63 (Malcolm) · #6 03-02-2015, 11:03 PM

Quote:

Originally Posted by glend

Thanks guys. The shed supply that will feed it already has an ELCB. Certainly glad I don't have to go down to 600mm - I've had enough digging after the footings and roof support posts, and the pier.

I remember digging only 300mm for a shed as well. There is a 600mm clause in the document but that is for barrier shield and only think it is related to distance away from the shield or something to that affect.

Not that much into electrical only electronics.