Electrical cable to the new shed. Sparkies?

[bennylaird]

Just think of the benefits of the ones you cut into this time... You can mark them for next time.

We had the RADAR cable in Butterworth (Malaysia) not only dug up but lifted up so high that it snapped. An 8 inch lead sheilded cable. Had to get the Poms out from England to fix it then we had to pump it full of Nitrogen every week thereafter. In order to do that you had to first remove the Vipers and Cobras from the cable pit.

[Pulpo]

I had power run to my shed 110m from the mains junction box.

Just two cables were laid around 10mm2 each, at a guess, in orange conduit.

This was to power my shed but also my house if I ever build one.

No earth cable is run along the ditch, just connected at the shed.

Not sure how many cables you are running to your shed?

As for the ditch digger pray for no rocks, big or small.

I hired the dingo digger with ditcher attachment; the rocks would derail the chain, a pain in the ass to put back on.

You must decide on the depth as you go, for going back to correct is not easy.

I think this is something I should have looked more carefully at, as I would hate running more cable just for the house.

Once again it comes back to very little information available, books on electrical wiring .

It sounds like you have a hell of lot more of an idea than I do.

Good luck

Pulpo

[Ivan in Oz]

Cliff,
Is the EARTH Wire required?
Can you get away without it,
and put down an EARTH Steak.....................OK!!!!! I know Stake
Something to chew over:confused:

[ozwinner]

I hired the dingo digger with ditcher attachment; the rocks would derail the chain, a pain in the ass to put back on.

Did you have to pedal backwards to get the chain back on??

Al

[Cliff Rogers]

...No earth cable is run along the ditch, just connected at the shed....

..Is the EARTH Wire required?....

That was the old way of doing it but it seems that they don't like multiple earth systems any longer... they want a single earth connected at the first switchboard.

In your case Pulpo, your shed may have been the first switchboard.

[boban]

How did you go Cliff?

Now I've had to go through the exact same exercise and I thought I would share the info I have obtained.

For building wire General Cable's website have published the ratings for their cables which are taken from AS3008. Here's the link to the PDF for single core cables you are looking at.

http://www.generalcable.co.nz/Austra.../4.1.2.1.6.pdf

They also have the multicore cable specs as well but they all start at 25mm2 for this supplier at least.

The thing that seems to have been overlooked is the fact that you already have a run from the supply to your house. Have you calculated the length of that run and the voltage drop for that distance? I have a 100m run to the meter box so Im using 25mm2 mains which will give me 74.53A per phase over that distance.

The formula is just a variation of that posted earlier. That is

A= 12 (being the 5% of 240V allowed) / (mV/Am / 1000) / length of run in metres

As an example the loss due to the resistance of 16mm2 wire is 2.95 mV/Am

For your run of 120m, 16mm2 wire will give you 33.89A

This is before you add in the length of run to your house. Depending on what is supplying the house, you may need to up the size of the wire or worse still the mains supplying the house.

Remember that this info has all been relayed to me Cliff. I trust that the sparkies on the forum can clarify whether this is accurate.

[Cliff Rogers]

How did you go Cliff?....

10mm² 3phase neutral & earth circular through a 40mm HD conduit.
It is in the ground but not connected at each end yet.

[boban]

I take it your house is not too far from the supply

[Cliff Rogers]

Yeap, the cable I put in is from my house to my new shed, 120M run.