# Forum Home Renovation Electrical  Running cable to shed.  What size?

## hoidey

Hi guys, Justa quick one.  I'm running some cable down to my shed and was wondering what size cable to use?  I am a fair way from my electrical box (about 60
Metres) and will be running just some lights/beerfridge with a view to a few power points for a couple of little machines later, not 3 phase.  And does anyone know who the best/cheapest supplier in the Tweed area is.

----------


## Moondog55

I think that th advice previously has always to go big and run a sub-board, this way you are covered for any upgrade and the cost of the cable and conduit is minor when you consider what sparkys charge per hour, I say 6mm*2 and the appropriate circuit breaker on the switch box

----------


## applied

6mm or bigger don't bother stuffing around with anything smaller.

----------


## hoidey

Ta guys.  So what is the next size up from 6mm?

----------


## applied

10mm but that's pretty massive for a shed six is pretty much standard.

----------


## chalkyt

Yep, all the answers point to 6mm. You will probably want to draw up to 30A. (By the time you have the fridge, heater in winter, toaster, jug, drill or lathe running, you can get up to 25 or 30A pretty quick). Underground, 6mm is rated at around 50A. and 4mm at around 40A. However on a 60 metre run, the voltage drop on 4mm at 30A will be more than the 5% permitted under AS3000. 
You will need to run the cable in 25mm conduit buried 0.5 metres underground. As suggested by others, a circuit breaker at your main board and a sub-board at the shed with main switch and RCD (residual current device or "safety switch") is the way to go. As with all things, "what you pays for is what you gets", so a couple of dollars extra on the bigger cable, safety of the RCD, etc is probably worthwhile. 
As most of the "cost" will be in labour to dig the trench etc you might be able to find a local electrician who will let you do the labour under his supervision and just charge for the connection and Certificate of Compliance.

----------


## NigeC

60 metres?
If your main switch/service fuse is 50A...
Go with 10mm
It won't fit in 25mm conduit, neither will 6mm by law.
Go with 40mm conduit
You'll need a couple of elbows too (to get up and down)
Sub board at the shed is a good idea, RCD's in sub board is good idea also
25A breakers at both ends (25A is heaps.)
This is opinion only without seeing the whole installation.
there are a few calculations to do based on your unique situation, get a sparky to recommend everything.

----------


## mattski2008

What law are you talking about NigeC with the cables sizes in conduits. 10mm and 6mm will both fit in 25mm conduit. We used to put 16mm submains in a 25mm conduit!!

----------


## NigeC

AS3000 Table C10, but I read the 6mm part wrong! sorry. 6mm flat TPS can go in 25mm, 6mm circ can't.
10mm in 32mm and above.
I like 40mm as you can put a draw string in for other cables later on.
I know the tables are for advisary only but I have found them to be perfect especially when it comes to bends (you know how hard it is getting cable through SR bends if it is tight)
Physically 10mm won't go through 25mm conduit I think, will post a photo to confirm if I'm right or wrong.

----------


## seriph1

WRT pricing - we had a guy here to provide an estimate and he wanted $420 for 100 metres of 6mm  -  I thought that was steep, so I googled and found a mob selling Aussie made 6mm for $220. I don't mind a bloke adding 20% for his trouble but that was a fair touch I reckon. Anyway, the moral is: get what you can when you can .... save along the way if you can be bothered and never just blindly accept that the price is just the price.....

----------


## NigeC

I just checked, physically 10mm cable WILL fit in 25mm conduit but it is tight and I wouldn't want to pull through 60m
40mm conduit is good

----------


## elkangorito

> AS3000 Table C10, but I read the 6mm part wrong! sorry. 6mm flat TPS can go in 25mm, 6mm circ can't.
> 10mm in 32mm and above.
> I like 40mm as you can put a draw string in for other cables later on. *I know the tables are for advisary* only but I have found them to be perfect especially when it comes to bends (you know how hard it is getting cable through SR bends if it is tight)
> Physically 10mm won't go through 25mm conduit I think, will post a photo to confirm if I'm right or wrong.

  For those who are unaware, there are many parts of AS/NZS3000 that are "Informative" & not "Normative". 
In this case, Appendix C is "Informative" (a guide) & not "Normative" (mandatory). 
I'm not having a go at you Nige but I'm wishing to cast more light upon the regs.  :Smilie:

----------


## NigeC

totally agree, not taking it to heart either!
the regs are put together by people a whole lot more experienced than I. I pretty much follow AS3000 like gospel (well if I followed gospel that is)

----------


## watson

Bless you my Son  :Rotfl:

----------


## Master Splinter

The regs are put together by a committee who may know what they are doing, but they really need to employ a professional technical writer to actually turn it into english.   
Just looking at the number of comments from sparkies on what/how the regs should be interpreted shows that they are falling short of communicating what they mean in an effective manner.   
Maybe even a questions forum on the standards australia website, where things could be answered by the actual standards people....(but somehow I think that's too difficult/takes too much time for them to worry about).

----------


## NigeC

I think they do have "forum" of sorts, that is why they bring out new regs every couple of years.
I think they like keeping it in "lawyer speak" in case us, working folk, make a mistake! 
I think regs go hand in hand with experience, from my experience!

----------


## moke

Hi,
I'm looking for a similar set-up as the OP but my shed is about 110 meters from the house.
What cable will suffice, 6mm or 10mm? Or is this distance going to be a problem?
Thanks,
Dean

----------


## iconnect

> Hi,
> I'm looking for a similar set-up as the OP but my shed is about 110 meters from the house.
> What cable will suffice, 6mm or 10mm? Or is this distance going to be a problem?
> Thanks,
> Dean

  Dean,
A quick calculation from table C7 in AS3000 using a 20A breaker as guide to circuit current would suggest 16mm cable as the minimum, with 25mm certainly not out of the question. However there are a few significant factors that can alter this and to get the most accurate answer I'd recommend getting a sparky over to take a look at your particular installation as he should be able to base the cable size on actual parameters (supply voltage, voltage drop to switchboard, actual circuit loading etc) and not assumed ones. It could make a big difference on a run of that length. 
Darryn

----------


## Belair_Boy

Just thought I would put my 10c in. 
I am just wiring up the main run to my house via the shed on the way.  165m in all with 50mm2 three phase cable (4x 50mm XLPE in 63mm conduit). The branch to the shed from the meter box is in 10mm2 and only about 10m long (50mm dia conduit).  You need to consider voltage drop on the longer runs as it becomes the overriding factor for a given current.  Better to go as big as can (within reason) rather than have to replace the cable when you decide you really do need 3 phase or want to run that welder you bought cheep on eBay. :Smilie:

----------

