Calculating Amp's

[ozwinner]

Hi All
I was just wondering if anyone out there knows how to calculate the number of amps that a copper wire can carry per Sq'mm.
I know house wiring is rated at 10 amps, but I have got some very serious wireing to the shed.
I will get the shed redone in 15 amps but not at the moment.
The wireing in the house and shed at the moment is 2.5 Sq'mm, and the fuse in the meter box is 16 amp.
I've just bought some new machinery, and want to see if its safe to run.

PS. if you see a blue glow in the sky over the Northen end of Melbourne, its not the Australis Borialus, its just me.

Cheers, Allan

[outback]

Oz, You will need the help of an eleco on this me thinks. It is not only the conductor, (wire) size but the length of the run also.
When an eleco needs to wire a shed or other similar thing, they need to calculate the number of amps available at the supply point, the number of amps required at the shed or whatever and how far apart it all is, they then look in their magic book, (probably puter these days) and bingo, the magic conductor size is revealed.

[gatiep]

a good explanaition and guide was given in a thread a while ago. Search the threads for, rewire shed, single/ three pase or 15 amp supply...or something to that effect. Somebody gave the ratings of the conductors in Amps per sq mm over ? meters.
Its here somewhere.
Cya

[AlexS]

Think it was Soundman gave the good oil

[gatiep]

Alex S

I am 99% sure that you are right. I thought it was him but you just kinda confirmed it. It was so well and thoroughly laid out that I really thought that Allan would get more than he expected from that post. It surely gave me some insight.....just a pitty the grey matter doesn't absorb too much anymore
Cya

[mkcl]

You really need AS3008 to work this out properly, as it contains the tables and formulae required. Unfortunately, it's a bit expensive for a one-off calculation.

However, if you post the exact details of what you are trying to do, someone may be able to run the numbers for you.

Michael.

[ozwinner]

Thanks Guys.
Since posting, I've come to my sense, weeeelllllll as close as I'll ever get anyway.

I'm going to give a sparky a call, theres one in town.
I gave one a call 6 months ago, I'm still wating for him to call, I hate being bumped, all they have to do is ring.

Cheers, Al the enlightened one.

[soundman]

Yep it was me.
those figures given were for flexible cables.

permanent wiring goes by a diferent set of rules
check out AS3000

in short without the obscure readings.

circuits with 10 amp outlets will be wired in 2.5mm cable with a 15 or 20 amp breaker. in a commercial application 10 outlets to a circuit max. (usually)

15 amp & 20 amp outlets are usualy wired directly to the switch board with their own individual breaker. in 2.5mm or greater.

It can all get very complicated, particularly with the current revision of the rules.

for a serious single phase shop i recon
at least 2 15 amp outlets (or preferably 20s) and 2 10 amp power circuits and 1 lighting circuit is a real good start
with a 60 amp feed.

get individual mcb/rcd (combined earth leakge/ circuit breaker) units for each circuit including the lights.

minimum if you have any decent machinery is 1x 15A (or 20) 1 x 10 circuit, 1 lighting. 40 amp feed.

I regret no putting a 60 amp feed to my shed.

cheers

[ozwinner]

Had a sparkie around last night.
He is going to price me a 60 amp board in the shed with 2x 15 amp outlets, Rcd, curcuit breakers, etc.
Then a seperate price to upgrade the house board, its from the 1970's so they are still fuses, no RCD etc.
Hope I dont die of shock when I get the quote.



Cheers, Allan

[coastie]

Make sure you are sitting done when you open it!!!

[ndru]

Hope I dont die of shock when I get the quote.

You won't die, but you WILL have a near death experience. All I can say is "move towards the light my son..."

[soundman]

go with the house up grade too.


I've never heard of a fatal shock from a quote or a bill.


but the electrickery stuff asks no questions & tells no lies