Kitchen Island Power

[Salem]

hi all, I need to have power run 2m along the concrete slab to our kitchen island for a single GPO. The kitchen hasn't been installed as yet and I need to dig up the existing tiled floor anyway so I wanted to take the opportunity to cater for any requirements for the electrical by digging the trench. I was hoping somebody might be able to give me an indication of the depth I need to dig the trench. Thank you.

[Bros]

Deep enough to take the conduit, use orange to give a bit of extra protection.

[cyclic]

Deep enough to take the conduit, use orange to give a bit of extra protection.

The laws from State to State may differ and you should be asking your Electrician because he is the one who has to certify the installation.

[Overkill]

Thread hijack:

I need to exactly the same thing, except on a wooden floor over joists. I am certain there are cables run in the general area, so what's the safest way to cut out a floorboard to either find an existing circuit or run a cable from a near-by GPO? I was thinking about running a circular saw down the edge of a board without quite cutting through and then levering it out. The kitchen is getting a new floating floor over the existing boards, so I don't have to be neat.

[Sparky Direct]

The safest way to cut the boards is to turn the power off at the main switch. Either use a battery powered circular saw or borrow some power from next door if using an electric saw.
Cut along the edge of the board then across it near where the nails are, this will be the cross floor joists. This way you will be able to put the cut piece of floor board back down and it will still be supported by the joists.
Generally, if a qualified electrician did the original work, the cables would be clipped at least 50mm below any floor board, so just cut 10mm deep and all should be fine. -
hope this helps

Sparky Direct

[billy101]

when running power to the island the electrical cable under the bench does that have to be in conduit.
thx :U

[Salem]

sorry to drag this back into the limelight. Didn't even notice all these updates. I'm fortunate enough to know an electrician and was given some feedback regarding how deep I should dig this trench in the slab. It was recommended I go down 75mm if using 25mm conduit. It's also been mentioned to me that my slab could be 100mm. Is this true? That's getting pretty close if thats the case I certainly dont want to be exposing earth or cutting deeper than I have too. Is there somewhere I can reference this in Aus Standards etc that will give me a definitive answer. I live in NSW and it'd be great piece of mind to know this is done correctly and I'm not digging deeper than I have too. I've got two conflicting responses and a little confused now. With all the floor work I'm doing in this reno it'd be nice to cater for this ahead of time. Thanks.

[Random Username]

From AS3000:2007...

3.9.4.2 Wiring systems near building surfaces.
Wiring systems shall be protected by one of the methods outlined in
Clause 3.9.4.4 if they are—
(a) concealed within 50 mm from the surface of a wall, floor, ceiling or
roof; and
(b) located more than 150 mm from internal wall-to-wall or wall-to-ceiling
corners; and
(c) fixed in position by either fasteners or passing through an opening in a
structural member.

3.9.4.4 Protection methods
Where protection of a wiring system is required, in accordance with
Clauses 3.9.4.2 and 3.9.4.3, the wiring system shall be—
(a) provided with adequate mechanical protection to prevent damage; or
(b) provided with an earthed metallic armouring, screen, covering or
enclosure; or
(c) protected by an RCD with a maximum rated operating residual current
of 30 mA in lieu of mechanical protection.

So chisel out enough to house the conduit, and make sure it has a RCD as your belt and braces approach.

And yes, 100mm is a fairly typical slab thickness for a house. If you go deeper than about 45mm you will then be cutting through the reinforcing fabric as well.

[Salem]

thankyou for all that info including referencing the Aus standards. huge help. Thank you..