View Full Version : HELP Need advice on getting a 15amp connection to my garage

16th Sep 2020, 10:53 PM
Hi folks,

I'm in the market for a new table saw and it seems that I'll most likely need to upgrade my electricals.

I called up a couple of different sparkys today and they gave me different information and I could use any input from this forum.

First electrician told me that because my house is so old, he will install a new connection at the meter box and take that 30amp cable over the house and into the garage and install the outlet for me for $400

Second guy told me that my current wiring is sufficient as my garage is on a separate circuit and he will install just an outlet with a safety switch on it for $350. He says there is no need to run a cable and just need a outlet for 15 amps and a switch.

The first guy was young, probably doing this for 15-20 years
The second guy looked like he's been doing this for 30+ years

Any advice on which option to go for?

I'm attaching a pic as well



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16th Sep 2020, 11:04 PM
ok, I'm not qualified to comment but even I can count. You want to add a 15A circuit in the garage, that is currently protecting a bunch of 10A outlets with a single 16A fuse. You need a new circuit. Take the first guy. No question, for an extra $50 you get no problems.

edit: also queue the forum moderators; WWF and ubeaut enterprises et al take no responsibility here - make sure you use a professional !

16th Sep 2020, 11:11 PM
Your garage has a 16A breaker at the breaker box so you should have at least a 16A cable running to the garage (its probably a 20A cable)
Hence a single 15A plug can indeed be connected to that line but it assumes you have nothing else on at the same time in your shed ie what about DC, lights AC, etc?
Also each 15A GPO should have its own breaker - independent of any 10A GPO or lighting circuits.

Because of this I would go for option 1 and get a separate breaker box installed in the shed and while you are at it get two 15A GPOs installed. One 10A Breaker and one lighting breaker. You should then end up with 4 separate breakers in the shed breaker box. Even if you don't get the second 15A GPO right away having a speared shed breaker box will make it a doddle to install it if/when you need it.

BTW he's right about your house wiring being old - this is clearly demonstrated by the old breaker box on your house.
I would seriously consider a complete upgrade of your house breaker box and then it will come with an RCD - those things save lots of people getting killed/injured including from being burnt to death by house fires.

If you install a shed breaker box it should also come with its own RCD.

17th Sep 2020, 10:47 AM
There ought to be a separate rcd for the house already, perhaps separate to the fuse board.
Certainly I believe in Vic it would have to be installed with any other work.

But I'm with the others, go for the new line and circuit.

17th Sep 2020, 01:45 PM
and at the same time change the old fuses for the circuit breaker style or just get the ones that just adapt straight into the existing blocks

17th Sep 2020, 07:25 PM
Technically, I believe that what you have at the moment is legit provided that the house is not a rental. However that status is only until you have any electrical work done, at which time it should be recertified as meeting current standards. That means RCD and circuit breakers become essential, so replacement of the fuse box becomes involved. It is legit to have the fuse box replaced with a modern breaker panel utilising individual combo breaker/RCD modules to replace the existing fuses provided that each circuit passes test to verify that the cabling and fittings meet current standards. Cost to do that could get close to $1K plus the extension for the garage provided everything meets test standards. It gets very exxy however if a circuit doesn't conform during testing or continually trips RCD's etc as this means that at least part of the house needs rewiring, possibly 2 people for a day pulling cables etc. I understand that rentals will required to have RCD's in Victoria from March 2021, which virtually dictates an upgrade for panels like yours in rental properties in Vic

I also suspect that the mains service is probably an older limited current one, either around 30A or 60A, and this may also be a limiting factor as to how much additional load can be placed on the system without upgrading everything from the supply pole or pit.

I would be opting for the first estimate, but would not be surprised if either ended up leading to a panel upgrade being essential.

17th Sep 2020, 08:13 PM
About 12 years ago I had a sub board put into my detached garage to provide power for believe it or not a major christmas light display, at the time we had old style quicklag breakers and no RCD on the house. The licensed electrician at the time said it was legit to leave the house board as it was as long as the new sub board was up to code as effectively he was not working on the existing house wiring or board.
Edit: this involved all new cabling from the main to sub board, fairly certain they dropped in a 6mm feed

Still ended up a few years later replacing the house board when we got solar installed.

The point is ask your electrician if it's possible to have a sub board installed for your shed/garage.

18th Sep 2020, 09:28 AM
You do have to bring installations up to current standards but only if you change them in any way. The main thing to ask your sparky is if he will provide you with an electrical safety certificate. He is required to by law. It is a legal document that states that all electrical installation work carried out by him has been installed and tested to the current regulations and standards and is safe to connect and energise. If he says you don't need one or he can't give you one tell him no thanks and use someone who will.
I can't comment on the two options offered because I haven't seen the job and don't have all the information. Either one could be correct. The add a GPO for $350 might seem a bit steep but GPOs with an RCD built in start at around $150 for a 10Amp. I don't even know if you can get a 15A version.

18th Sep 2020, 09:46 AM
The cable is the same only the breaker and the outlet need changing. But if you’re only starting out you’re likely to buy more gear and draw more power in the longer term. Putting in another circuit makes sense, just get them to put the maximum number of outlets on it around the shed, then you won’t need to get them back later.

18th Sep 2020, 12:44 PM
Technically both guys are correct, as all circuits have headroom for safety reasons. If you're only getting one installed and are not going to be piggy backing the connection you'll probably be fine. However, IMO you'll want a second one for say a dust collector. Which will most definitely mean you'll want a separate circuit for the 15amps. If you don't plan/need a second outlet then either choices will be fine.

The price of the first quote is about right the cost of installing 15amp circuit, as the cost will depend on how difficult it is to run the wiring and length of run. to me you're getting much more bang for your buck with the first guy.

18th Sep 2020, 06:06 PM
as I read the fuses in your switch box


1. your garage is wired for a light and single 10 amp GPO -- all protected by a single 16 Amp fuse.
2. your supply is single phase -- there's not enough circuits in the fuse box for more than single phase. I'm almost tempted to bet my balls on it.
3. You definitely intend to run a table saw and dusty, and down the track MIGHT be running a planner and dusty, or a large router and dusty, plus ???
4. and the fuse box wiring definitely predates Australia's switch to 10 digit phone numbers which started in 1994. -- making the whole shebang likely more than 30 years old. And possibly pre-1980s.

Upgrading your garage supply might constitute a major electrical upgrade and necessitate bringing in a third wire (you will already have two) from the power authority.

Also, while the sparkie is on site, ask him to confirm that the light circuit is really 28 Amp. Normally I would expect that a light circuit would be protected by a 16 Amp fuse.

19th Sep 2020, 10:39 AM
Regardless of how they do that circuit, change out those fuses for breakers and get some RCD protection