Non-welding electrical question

[Legion]

New toy planning time. I have 400V 32A socket. I have 10A sockets everywhere. I don't have 240V 15A. I want a compressor. Eventually I might want to also run a plasma cutter, at the same time as the compressor. Maybe also have my three-phase Dynasty plugged in at the same time as the compressor since I'm lazy. Dynasty uses about 8A. Three phase compressors I'm interested in use about 10A. The plasmas I've been looking at use less than 16A. Is there any law against getting a sparky to wire up a 32A plug with a 20A/10A or 16A/16A or 10A/10A or whatever socket combo? I.e. a three phase double adapter? I've never seen such a thing and I presume it's because of the specificity of three phase equipment compared to the nature of 240V 10A equipment where you can buy off the shelf and daisy chain ridiculous amounts of adapters.

[soundman]

A three phase double adaptor is most definitely illegal......seen a few used...but illegal.

I not shure of the fine detail in an industrail context......but it is common AND legal to have a three phase break down board.

Where a three phase plug tails off to a portable switchboard with whatever sockets add up to the total and circuit breakers that match.

for example most stane shows run a 3 phase break down from a 32 or 40 amp plug....the board then has a quantity of single phase powerpoints all protected by the appropriate curcuit breakers...I have one on the shelf with my audio gear.
This only works on a three phase socket with a neutral connected.

As I say not sure of the detail in industrial context.....but a break down board with 3 x 10 amp 3 phase sockets would do the trick...BUT it might just be cheaper to do it as a permanent fixture......it would save you about $250 in 3 phase plugs and cable.

cheers

[Legion]

OK, makes sense. I tend to prefer Clipsal gear and they don't seem to have any boards like that, just 240V variations. Other generic companies make things that might do but I might just get a new 400V circuit put in. I got a rough estimate for a 240V 15A circuit of $450 the other day and my three phase socket cost a bit less than that, but I supplied all the components. I still have enough cable and a breaker to fit a new circuit, just need a wall socket and labour. The equipment I'm interested in costs more in three phase form but since I tend to like excess capacity it's probably better to go that way.

[soundman]

If you are thinking about a 15 amp single phase socket and circuit...dont bother..go 20 amp.

The costs and the cable required are pretty much the same, the 10 and 15 amp plugs work with the 20 amp socket and a lot of stuff is comming with or needs a 20 amp socket.

Ya won't find any off the shelf break down boards except those designed for theatrical use.

cheers

[Legion]

Ok, but if I have to pay for a new circuit anyway I will just get another three phase, probably 32A again. E.g. I doubt I'd buy a 240V 10A compressor, they just seem a bit limited. And 240V 15A ones are marginal so why not just go for a three phase one? I just hoped since I've got an existing 32A socket I could run two lesser devices off it but you've set me straight that that's not possible. I can buy a three phase compressor now and run off my existing circuit and save up and factor in a new circuit if I manage to justify a plasma cutter next year, which that other thread made me want. That and a magnetic drill are top of the wish list.

[soundman]

If I had three phase, there would be no way I would entertain a single phase compressor.....and remember 3 phase goes cheaper second hand.

cheers

[Marc]

What you are talking about is called a sub-board.

You get 3 phase in the shed say with a 10mm 4 core plus earth cable. This cable will have circuit breakers of say 60 amp per phase. You need a main switch and from there you go either 6mm for 32 amp 3ph powerpoints each with it's 40 amp c braker or 4 mm if you want a few 20 amp 3ph powerpoints. with their 30 amp c braker.
If you want single phase 10, 15 , 20 or 32 powerpoints you will need to wire each one with their respective size wire and c braker
10 can be all on one 2.5 wire, 15 must have each its single circuit on 2.5mm, 20 needs 4mm and 32 needs 6mm again each with it's own circuit braker of adequate capacity. You would hook them up on different phase to balance the load.
A sub board makes wiring simple because it is all contained inside the shed. Short runs, and each circuit with ti's correct circuit braker. Forget hooking up a smaller powerpoint to a bigger one, unless you want to have yet another box with a circuit braker next to the bigger powerpoint (not a good idea)

Remember that the 20 amp 3 phase powerpoints are cheaper and have thin pins. The 32 have thicker pins will not plug in them.
A 3 phase 10 hp compressor will happily work on a 20 amp 3 phase powerpoint, in fact only draws 15 amp per phase and you could wire it with 2.5 mm if you wanted. Of course 4mm is better.

[LordBug]

...and remember 3 phase goes cheaper second hand.

cheers

Everything tends to go cheaper second hand than when it's new, I've otherwise yet to see 3 phase 2nd hand gear asking for less than single phase stuff, haven't come across any of these bargains yet

[soundman]

Hell, you haven't been to too many auctions then......I've seen single phase things like drill presses go for more than retail and the same unit in 3 phase next to it hardly raise a bid.

there are definitely three phase bargins to be had out there.

cheers