Electrical Sub board in shed.

[Lappa]

Has anyone fitted an electrical sub board in their shed? I'm looking to get a 60A unit fitted if possible. I'm after info on whether its feasible and approx cost before I start bothering my local electricians for quotes.

Cheers

[NCArcher]

Yes, generally a good idea but existing capacity will determine what can and can't be installed.
I'll send you a pm when I get back from shopping.

[BobL]

What machines are you planning on using?

I have a 20A sub board and a 32A sub board and ammeters on most machines and the sub boards so I can what is going on.
Is pretty rare that I get anywhere near full capacity.

[Pearo]

I have a 64A sub. Ran 2 * 6mm2 TPS cables from the house (approx 50m) which was probably an overkill but could be upgraded to 3 phase.

Material cost:
100m roll 6mm TPS (twin and earth) - $215
12 pole sub board enclosure - $20
2 63A breakers - $10
RCBO's for circuits ~ $100.

Could not tell you labour, but if you run the cable and get everything in place for the sparky then it will cost you way less. I am a sparky by trade, but not licenced, so I did everything then got my sparky mate to come around and do the final connection to the switchboard.

I could not tell you what size circuit I have from the grid, but its substantial and I did not have to upgrade that part. If you need to do that the cost would be a lot more because you may need to sling a new cable from the pole to your house.

[Chris Parks]

The one big advantage is if you don't skimp on the feed to the sub board you can add machines etc without having to go any further back than the board in the shed. makes life a whole lot more simple and does not restrict you in the future. I am sure Tony will give you the good oil on the whole thing.

[woodPixel]

Sure do. Best thing I ever did.

The sparky had me do all the muscle work before he came. I drew in the fattest cable I've ever handled from the main board. It was 20 meters. There is a 60 amp RCD on that end and a sub on the studio. Grovelling under the house and hanging it all "just so", then doing all the sheathing and wiring here to spec (hard work). He and a slave did the points and box on the wall (they took 3 hours)

I've had circuits added for new aircon (3.5kw Daikin installed 2 weeks ago (whew!!!)), a 20amp circ for the TS, four fifteen amp circs for lathe, compressor, dusty and bandsaw. Each has its own RCD.

Im pretty chuffed. Of course, not everything is on at once.... the aircon has been running non stop* for the last two days, the DC and one other big tool.

The original 16 amp circ remains, which has been RCD'd and is used for all the "kitchenette nook" crap... kettle, microwave, chargers, computer

Apparently we cant get 3 phase here, but monster amps are... Have to admit I don't get how it works amp-wise, but the electrician was very surprised (did he say 100? Is that feasible? The house isn't far from a big shop)

All up I paid $950 for everything.

* 980 watts, costs me 16.8 cents per hour!!!! Its 22° in here!!! Not 40 like it used to hit on 30° days.... last two days have been 41° outside!!!!

Overall, I consider that upgrade the single best thing Ive done in 6 years. The Aircon has been a blessed life saver. If anyone needs a top-notch aircon dude who is fantastic, drop me a line.

[Lappa]

Thanks for the feedback fellas.

My "added extra" is that I'll have to have the main board replaced as well. At the moment the shed is piggybacked off a power point circuit in the house - has been this way even before I bought the house almost 40 years ago.
I've realised that I'm going to need some 15A GPOs when I upgrade equipment for retirement so I may as well spend the $$$ and upgrade everything while I'm still working.
Didnt know about 20A circuits Woodpixel, thanks for the info.
Cheers - Peter

[woodPixel]

Just checked my board, since its only 4 feet from where I write this (in the now 21° glory). It says C20 on the clipsal RCD.

I went a bit nuts with RCDs, for I fear electricity, plus it was explained to me they are dirt cheap. So, everything received one.

I was advised that some stuff might trip them (like the dust collector firing up) and if they did, he would come back and add some other douverlacky to stop the misbehaviour. It hasn't, so thats avoided.

Overall, my sparky was pretty tame about me wanting to save money. I really don't think he wanted to be grovelling under a dusty house and climbing over shelves. It was all just pipes and cord pulled though, plus I had a chance to do a really neat job of it.

One other good thing about a subboard, is that I have 6 other "spots" to do more stuff when more dosh is found... doing the lights properly, doing the kitchenette properly, doing the upper "day room" properly, etc. This house is 60 years old and built too cheaply, too fast and with no consideration to the future. Every single upgrade shows the complete mental paralysis suffered by Canberra's designers and builders in the mid 60's. Every time I go under it I sneer at the shortcuts, cheap hacks, stupid brickwork and useless layouts. The roof is worse.

[BobL]

Having an ammeter on most machines and the main breaker box is very instructive.
For machines that don't have an ammeter I have a short extension cord with an ammeter built into it.

The only machines that draw their stated ratings are the 3HP DC (9.2A) and the 4.1kW cooling (1250 W running power) air con draws 5.2A.
The two machines that can draw more than their stated ratings under normal operation are the 4HP compressor (up to 16A) and the 3HP TS (up to ~12A)
All other machines draw a lot less than their motor rating. e.g. the BS is 3HP (so connected to a 15A GPO) but I never seen it go over 6A and I usually run it at around 4.5A.
The 3HP sander gets to about 7A under heavy load but mostly its running at about 3A.

15A machines should be on their own GPO, circuit and breaker, but this adds up real quick and really clutters the breaker box so you can judiciously pair appropriate machines onto a double 15A GPO provided of course you don't run them under load at the same time.
The DC and the welder/plasma are on the same double 15A GPO. The DC is not used when welding/cutting as I have a fume hood with its own extraction fan on it.
The 3HP sander and the TS are on the same 15A double GPO.
The TS and router (in TS router table wing) are also on the same 15A GPO
The plasma cutter and TIG welder are swapped between a HD 15A short extension cord.
The only machine on its own 15A GPO is the compressor.

Everything else is on two 10A (16A CB) circuits.
For lighting there are 19 LED fluoros running on two lighting circuits.

[woodPixel]

Indeed BobL. It makes me wonder why the average suburban house here gets 100 amps delivered to the box.

We can put in some monster aircon and drive some monster machines and its all A-OK.

Strewth!

[Pearo]

It makes me wonder why the average suburban house here gets 100 amps delivered to the box.

Strewth!

Once you add stoves/ovens/hot water systems and then demand can go up pretty quick. Dont forget coffee machines, toasters, dishwashers etc... Got to have all the mod con's!

[Lappa]

Woodpixel - When you said 20A circuit I somehow thought a 20A plug - sorta like a 15A plug but bigger - must be the heat
Tony was good enough to run his eyeballs over some pictures I sent him and has confirmed that the whole main board and meter plus some wiring has to be replaced as a starter.
I'll get these done ASAP then worry about the sub board down the track.

[BobL]

Woodpixel - When you said 20A circuit I somehow thought a 20A plug - sorta like a 15A plug but bigger - must be the heat

There is such a thing, and 32A ones as well, they look like 3P plugs.
4/5HP machines are supposed to be connected with these.
Weatherproof Male Straight Plug Single Phase 3 Pin 20A 240V , PDL Matrix MP320 | eBay

[Bohdan]

They also come as a regular 3 pin plug just with wider pins. The beauty of these is that you can plug the regular 10A and 15A plugs into the socket.

20A Plug Tops - HPM

[NCArcher]

The 32A plugs came into being while I was working as a domestic sparky. They were designed and approved for one purpose at the time.
There was a building boom and plenty of new homes going up. However the large fixed appliances like stoves and cook tops were being stolen from nearly completed homes. Some more than once from the same house.
The builders and sparkies worked with the supply authorities and the manufacturers (Clipsal) to design a large capacity plug and socket. We would install a lead and plug on the cooking appliance and a socket on the wall.
The day the builder handed over the keys to the new owners he would bring in the appliances and plug them in. Security was now the owners problem.