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:oo: - must be the heat:D
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:oo: - must be the heat:D

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 (http://www.ebay.com.au/itm/Weatherproof-Male-Straight-Plug-Single-Phase-3-Pin-20A-240V-PDL-Matrix-MP320-/261714255564?hash=item3cef629ecc:g:jWIAAOSwwTlUnkq1)

[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


(http://hpm.com.au/products/20a-plug-tops)

[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.

[Lappa]

First minor hiccup. I'm serviced by Ausgrid and apparently in Sept 2016 they downgraded the maximum available single phase service fuse to 80A.

[Chris Parks]

First minor hiccup. I'm serviced by Ausgrid and apparently in Sept 2016 they downgraded the maximum available single phase service fuse to 80A.

For new installations?

[Lappa]

Chris. I've sent an email to Ausgrid for clarification but the reply didn't answer the questions so I'll phone them. The electrician today said he can only install up to 80A even with a new meter - my old one is 60A. It looks like a NSW Govt rules update to all providers. They still talk of a 100A service fuse but they now have a Meter protection device which is 80A. They can be combined in one but that unit is limited to 80A or they can be in series, 100A first then 80A to the meter or each meter if multiple meters. I'm reasonably confident it's for all new installations but not sure if it applies to existing installations that have work done after Sept 2016.
Hopefully Ausgrid will clarify tomorrow. Their technical section only takes phone calls to 11am.

additional info - found this

http://www.resourcesandenergy.nsw.gov.au/energy-supply-industry/pipelines-electricity-gas-networks/network-connections/rules

[Lappa]

Reply from Ausgrid confirms 80A maximum fuse.

When asked what was the maximum current for a single phase residential the basic answer was

" The maximum rating of a meter protection fuse is 80 Amps under the new NSW Service & Installation Rules,"

plus references to existing components, neutral links, earth stakes etc. coming into play.

[Lappa]

:oo::oo:

As as I suspected, whole main board and meter needs replacement. In its original position, it's too high to meet current regulations. Moving it down will interfere with the front screen door so it has to be moved. Concensus is to move it to the side of the house - approx 4 metres. Old power points (5) in the old part of the house have to be rewired to meet current regs. Existing connection to shed to be placed on its own 20A circuit rather than piggy backing off existing circuit as a temporary measure until the sub board circuit is installled.

No change out of 4 big ones.

Sub board and circuit will have to wait:(

[BobL]

:oo::oo:

As as I suspected, whole main board and meter needs replacement. In its original position, it's too high to meet current regulations. Moving it down will interfere with the front screen door so it has to be moved. Concensus is to move it to the side of the house - approx 4 metres. Old power points (5) in the old part of the house have to be rewired to meet current regs. Existing connection to shed to be placed on its own 20A circuit rather than piggy backing off existing circuit as a temporary measure until the sub board circuit is installled.

No change out of 4 big ones.

Sub board and circuit will have to wait:(

oh dear, sorry to hear that.

[Lappa]

Two guys, 7 hours and I went from this


407063

to this

407064 and this 407065


plus all the old rubber and cloth wiring replaced.


Saving up now for the sub board

[Pearo]

Looks like it was a good investment even though the shed upgrade is delayed.

[Lappa]

After some discussions and great advice from NCArcher, I've decided to install a 32A sub board rather than the 60A I was originally looking at and what the Electrician that rewired the house suggested (the electrician was saying he always installs sub mains for the max. just in case of future developments)
The electrician that came around today concurred with NCArchers advice. I already have a 20A circuit to the shed that has two year old wiring to the house and now new wiring connected to it and the new main board.
This will be utilised for the lights, fans etc. and the sub mains will have two 15A GPOs plus a number of double 10A GPOs for the power tools.
So probably save a bit on the smaller wire gauge but should be easier to install.

[BobL]

After some discussions and great advice from NCArcher, I've decided to install a 32A sub board rather than the 60A
.
.
I already have a 20A circuit to the shed that has two year old wiring to the house and now new wiring connected to it and the new main board.
This will be utilised for the lights, fans etc..

Sounds exactly like what I did. :)

[Lappa]

The cable distance to the shed is about 20m. Is 6mm twin + earth TPS O/K? The guy reckons is good for a 40A sub board.

[NCArcher]

Yes, 6mm will be fine. Depending on how it's installed you could get a bit more out of it. The current carrying capacity changes with its ability to get rid of heat. So a cable installed in air can carry more current than a cable surrounded by insulation in a wall or roof space. With a longer run of cable the resistance of the cable increases and the voltage drop goes up. Max allowed voltage drop is 5% so 12 volts for 240V supply. Your run will drop about 6 volts.

[Lappa]

Thanks Tony. It's being installed in conduit running along a Bessa block retaining wall behind a lot of shrubbery. We use the same 5% rule for critical circuits in automotive as well.

[BobL]

I had a 6 mm^2 4C+E line run even thought the house doesn't have 3P because at that stage (2011) the street was going to be converted to UG power in 2013 and I was hoping to get 3P connected at the same time.
In the meantime I discovered VFDs and now have 11 of these in my shed
Now we are not getting 3P power in 2019 but I am not sure we will bother to get 3P power.

On another matter, it's a 40 m cable run and the mains V in the shed is usually around 240V but I have seen it as high as 252V and hot days like today it's 229V

[Sawdust Maker]

It's good to see Tony's consistent in his advice

[NCArcher]

Thanks Tony. It's being installed in conduit running along a Bessa block retaining wall behind a lot of shrubbery.
That installation actually derates it a bit to 37 amps but it will be fine.

[Lappa]

Just a bit more info on these contemplating doing the same as me.
The reason I asked re the 6mm twin + earth TPS was not regarding the wire size but rather the wire configuration. One guy wanted to run 6mm SDI wires plus an earth which was more expensive.
Cheers

[NCArcher]

Two single cores actually increases the current carrying capacity a little bit. He probably has a couple of rolls of 6mm SDI sitting on the shelf. Good opportunity to use it up.

[Lappa]

At last a fine day and the sub board is in plus 3 x 15A GPOs.:2tsup: Great guy, will use him again. Less than 1/2 the cost of some of the quotes. One guy quoted 3 days labour, this guy and his mate arrived at 10:15 and out at 1:45pm.

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