# Forum Home Renovation Electrical  Can electrical & water be ran in the same trench?

## McOz79

I'm currently digging a trench 600mm deep to run some electical cable from my house to my shed, since the cable will be in waterproof conduit, I was wondering if i was legally allowed to run mains pressure water pipe in the same trench?  
Thanx for the help,
Scott

----------


## applied

minium seperation between low voltage (240V- 415) electrical service and water service not greater than DN65* is 100mm. so make your trench atleast 300mm wide.
if you are running the conduit yourself makesure you replace the dirt with dolimite sand for the first 300mm and then place marker tapeto comply with clause 3.11.4.5 and 3.9.8.4
metal pipe may need  to be equaly bonded to earth it should be already depending on the age of the home.  
goodluck 
dn refers to internal measurement if pipe.
where in adeliade are you? can organise the tape or parts for you.

----------


## McOz79

Thanx  for the help mate, yeah i live in the Port Adelaide area. Haven't got conduit and need 6mm Square cable my sparky told me. Come to think of it, don't have water pipe either :Biggrin: . Can you get parts cheeper than the hardware store?

----------


## applied

If your in the port go direct to PR electrical across the road from KFC or rexell next to the chirch back up the road a few shops both on commercal rd for the conduit and bends they will proabably do trade prices for you.  
what sort of length run are you going to need? 
Your sparkie is probably going to be the cheapest for the cable unless you buy a whole 100m drum (about $700) 
If you opt not to have any breakers in the shed you could go a 4mm mixed circuit.
simmilarly if you have a sparkie he should be able to get the marker tape it usually comes on 500M rolls.

----------


## McOz79

Thanx for the tips, need about 30m of 6mm. Yeah my sparkie mate said he could give me some tape and other bits and peices. Is it red tape for electrical and blue for water? You know what water pipe to lay in a trench of 12m length?

----------


## applied

its orange tape for electrical red is usually assosiated with fire service and detection services. i would doubt that you would need tape for water check with the pumbers on here.

----------


## McOz79

Will do, thanx applied

----------


## Moondog55

Only thing I will say is if your sparky said use 6mm<2 then that is what I would use, and put in a sub board.
Using a sub-board will give you more flexibility in the future, it is what I would do even though it could cost a little more

----------


## McOz79

Yep, we are putting a board in the shed with seperate breakers for each curcuit, one for a 15 or 20 amp pp to run a welder, etc.

----------


## mattski2008

300mm of sand is going way over the top!!!!!!!!!
Sheathed cable in a conduit is a Cat A system and can be buried without futher protection.

----------


## applied

credit to mattski2008 he is technicaly right if you interperet conduit bedding as mechanical protection and not cable identification.
i am assuming he is a very lucky tradesperson who has not had the displesure of trying to dig up and repairing a faulty underground cable or pipe after miss unlicky digs a hole in there yard.
for the sake of twenty bucks why would anyone bother.
reminds me of a saying, goes a little like this *"The bitter taste of poor quality remains long after the sweetness of a cheap job is long forgotten"*

----------


## sundancewfs

If you've got a trench open think of other things you might need in the shed...... 3 phase, ethernet cable, TV cable, gas, alarm, switch wire circuit so you can switch lights on in the shed from the house, a feed that comes off the trench 1/2 way along for a driveway lights or outdoor power point for garden lighting, an empty conduit with a draw wire in it for any future services you might want to pull...... Digging another trench at a later date is a pain and expensive.

----------


## McOz79

Ah, empty conduit with a draw wire! Thats a good idea might have to use that one

----------


## Bloss

> Ah, empty conduit with a draw wire! Thats a good idea might have to use that one

  And a decent size with wide radius bends.  :2thumbsup:

----------

