Thread: Q for sparkies - new supply

Yep, same. I completely forgot about this thread, been to busy in my own little world. Will size it up when in the office next (if I remember)

ok, after the rush of responses to calculate the cable size i've downloaded 'gencalc' to have a few guesses.

put in 40A current per phase (interpreting forum responses is this correct so in total 80A for the two phases in total?)
voltage 240v
5% voltage drop
330m run of cable
single core
underground in single duct
single phase


it comes up with min size 50mm Cu (70mm Alu) which i need 2 of plus neutral (same size?)

or do i put it in as 480 volt which for for 80A comes up same size Cu cable but Alu goes to 95mm?

or third, i've got no idea what i'm doing?

Back in 20!

OK, I punched in,
330m
4% volt drop
480V
100A
100Amp c/breaker
buried in conduit
XLPE


70mm2 copper (x3)
95mm2 aluminium (x3)


I wouldn't go any smaller personally.

cool !

service with a smile



what size conduit will they fit in?


thanks vern. now i can have a look at the $

some rough numbers just for cable costs :

70mm say $9.9 metre
70mm XLPE COPPER [XLPE70] - $11.00 : Electrician Supplies, ready and available for you online right here

cable cost $9801 for 330 metres

50mm say $6.6 metre
50mm XLPE COPPER [XLPE50] - $7.70 : Electrician Supplies, ready and available for you online right here

cable cost $5841 for 295 metres + say $600 for pole = $6441

difference $3360 so not worth sneezing at if get a pole put in to reduce span

caveat - dropped amps to 80A and voltage drop to 4.1% from vern's figures so kinda shows there's merit in looking at the pole option. i'll have instantaneous gas hot water, gas hot plates and wood heating so have to understand if 100A a necessity. anyway will now have to find a sparky who can actually communicate and discuss options!

thanks for responses vern & everyone else.

Aluminium I say, would be 1/3 the cost. Actually I have my price for th 95mm on my computer, I bought 660m of it the other day. However I would prefer to pm you the cost.

Pibby,

Not wanting to derail your deliberations, but why not drop the idea of connecting to the grid and install a stand-alone system based on solar and maybe a small wind turbine.

Not sure what you pay for power and connections in Tassie, but in SA, it's often cheaper to install solar and battery backup rather than pay for bloody expensive poles and/or underground cables, then pay more than 30 cents per kWh thereafter.

Strongly suggest you get a quote from a reputable (and communicative!) solar installer to see what the price comparison might be. The panels are now very cheap, and prices for Lithium Iron batteries are falling steadily. They're virtually maintenance free compared with the old battery technology.

Good ,luck,

Alan