Adding 240v to my garage

[GreenEnvy22]

Hi all,
I searched but couldn't find an answer to this particular setup, so just want to make sure I can do what I want to do. My boiler is currently two 1500w 120V elements, want to switch to a single 4500 or 5500w 240v element, for a 16 gal boiler.

I have a detached garage, it has a steel jacketed cable coming from the house in an underground metal conduit. There are red, black, white wires in it, no dedicated ground. I'm assuming the steel jacket is ground. Wires are 12 gauge.
It comes into a cutoff panel, see photo with the two red 20A resettable fuses.
In that cutoff panel, there is a ground screw with a white wire attaches to the box and goes upto the garage panel. So ground i think comes across the metal jacket from house, which grounds that whole cutoff box, ground is then brought to the panel via this white wire (and probably also by the steel jacketed cable going to the panel).

The panel is an old SquareD QO loadcenter. There are two free slots right now (though I could gain an extra one by removing the 120V outlet I added last year for brewing)
I don't see anything in either of these two boxes joining neutral to ground (which is good right, that should only happen in house at main panel?). However I do get tone on my multimeter if I test for continuity between a ground and neutral plug (maybe going all the way back to house).
I also do get continuity when I test ground between house outlet and garage outlet.

So my question is, can I add in a two pole 240V (30 or 40 amp) GFCI outlet to this panel safely? I know I'd need to move the one breaker in there over to get a double wide spot.

I'd then install a 240V outlet beside the panel for my boiler. Do I still have the option of a 3 wire or 4 wire setup for that outlet? Was thinking if I do 4 wire, I can then have a junction box on my cart (wood cart holds my boiler and mash tun so I can easily move out of the way when not using), which will also provide 120v (with it's own breaker in the junction box) for my pump. I have an SCR (not PID, just potentiometer for controlling power) for controlling the heating elements now. If I can only do 3-wire, I'd just have a separate power cord coming for the 120V stuff.

Thanks for any input.

 

[ITV]

With a 12 gauge wire feed you are limited to 20A breaker. To install a larger breaker would require to scrap what you have and have larger gauge wires/conduit along with a new breaker panel to be run to your garage provided that your house circuit breaker panel can handle it.

 

[GreenEnvy22]

There is 20A on each 120V leg/phase of the circuit, I thought that meant I could do 40A across the two, as each would only be providing 20A max, still protected by a breaker from going over 20?
Obviously I'm no electrician, just know enough to be dangerous

So if I needed more power to the garage, I'd need to pull 10 gauge through the conduit, hopefully using the old 12 gauge to pull it through. Otherwise I'd be limited to a 4500W element on a 20A 240V GFCI?

 

[ITV]

20A on each leg would still be a 20A 240V circuit since a 240V circuit is 120V on each leg.

Just looking at your photos, I am guessing that the screw in breaker panel lugs are only rated for 20A if that which means that if you increase the circuit rating you would need to replace this panel.

10 gauge wire would give you 30A per leg. Without knowing further details (wire distance between your house breaker panel and the garage, size of the existing conduit) may require larger conduit.

Keep in mind I am giving you suggestions based on the limited information (photos and description) that you have provided. I suggest getting the advise of an electrician if you would like to upgrade the electrical in your garage.

 

[GreenEnvy22]

Of course, thanks ITV.

 

[Bobby_M]

If the conduit is large enough, you might as well pull 4 x 8 gauge wires so you can put in a 50 amp 240/120v. If you do 10 guage wire, that limits the whole garage to 30 amps. If you use a 5500 watt element, that's 24 amps leaving 6 amps for everything else in the garage from lights, pumps, etc... at least while you're brewing.

 

[ehall]

what bobby said, 8g wire, and run 50amp. that means you can run other things thru that outlet if you want to. also get a GFI breaker.

 

[GreenEnvy22]

For now I've ordered a 20 amp GFCI, ran 10/3 wiring from the garage panel to a new dryer outlet (4 pin) in garage. This way when I get a chance to replace the 12 gauge in the conduit with 10 gauge, I'll be ready. 30 amp will be plenty for me unless I get an electric car, but then I'd be adding an outside outlet for that anyway, and where i park my car in the driveway is right beside where the breaker panel is in the house.

 

[ITV]

I hate to be the Electrical Buzz-Kill but you should have run 10/4 to the new dryer outlet since the new dryer outlet is a 4 blade (2-hots, 1-neutral, 1-ground).

 

[Brumateur]

I hate to be the Electrical Buzz-Kill but you should have run 10/4 to the new dryer outlet since the new dryer outlet is a 4 blade (2-hots, 1-neutral, 1-ground).

10/4 required only if you are going to use 120V out of that cable. If it's for pure 240V service 3 wires is enough - 2-hots, , 1-ground

 

[renstyle]

I hate to be the Electrical Buzz-Kill but you should have run 10/4 to the new dryer outlet since the new dryer outlet is a 4 blade (2-hots, 1-neutral, 1-ground).

Since this is a cable run thru a wall, and not an extension cord, I'd always assumed when speaking of "10/3 romex" it's always implied "w/g". Three insulated wires and a 4th, bare ground wire.

If we're talking just an extension cord thru a room, 10/3 is just 3 conductors.

Since this is "new construction" I don't think there is a code-compliant option to use actual 3 conductor cable from the GFCI in the box to the NEMA 14 anyways, there has to be a ground wire in there.

 

[GreenEnvy22]

Yes this is romex in wall , so it 4 wires total. Three conductors in one bare ground (red, black, White, bare).
Package is labeled 10/3.

The cord going from my controller box to the heating element, will only be three wires. The two hots and a ground.

Sound right?

 

[ITV]

10/4 required only if you are going to use 120V out of that cable. If it's for pure 240V service 3 wires is enough - 2-hots, , 1-ground

True except the GFCI breaker requires a neutral.

 

[ITV]

True except the GFCI breaker requires a neutral.

My bad, I was thinking of the load side, your correct the line side does not require a neutral.

 

[renstyle]

Yes this is romex in wall , so it 4 wires total. Three conductors in one bare ground (red, black, White, bare).
Package is labeled 10/3.

The cord going from my controller box to the heating element, will only be three wires. The two hots and a ground.

Sound right?

If you are only providing 240V to purely resistive elements, correct. Two hots and a ground.

Only if you needed 120V for a controller, etc would the neutral need to be carried in the cable as well.

 

[Brumateur]

If you are only providing 240V to purely resistive elements, correct. Two hots and a ground.

Only if you needed 120V for a controller, etc would the neutral need to be carried in the cable as well.

Many PIDs can be powered from 240V, so it;s not a problem to make a pure 240V controller.

 

[renstyle]

Many PIDs can be powered from 240V, so it;s not a problem to make a pure 240V controller.

Yeah, I figured with as many electron-centric rigs in countries != North America they have worked around that particular aspect.

 

[doug293cz]

Yeah, I figured with as many electron-centric rigs in countries != North America they have worked around that particular aspect.

It's really the advent of switching power supplies that made input voltage agnostic devices economically advantageous. They don't care what the input voltage is (within reason) and most don't care if input is AC or DC. And since you can get everything except the output filtering components (inductors & capacitors) in a low cost IC, it's cheap to include the capability in products (cheaper than making and supporting multiple models with different input voltages.)

Brew on

 

[Craiginthecorn]

If you're adding 240V to a garage, I would suggest that you include the neutral wire and to make it at least a 40 amp circuit. Electric vehicles are coming fairly fast. When I bought my EV, I installed a charger and the State of Illinois paid half of the cost of the charger and circuit. I use that circuit for brewing now.

 

[renstyle]

If you're adding 240V to a garage, I would suggest that you include the neutral wire and to make it at least a 40 amp circuit. Electric vehicles are coming fairly fast. When I bought my EV, I installed a charger and the State of Illinois paid half of the cost of the charger and circuit. I use that circuit for brewing now.

The wall outlet by code <must> be wired with 4 wires, so that part's covered.

OP mentioned 10/3 'w/g', which is good for 30A, tho limited by the 20A GFCI breaker.

40A may not be possible in the garage on a single circuit depending on the feeder lines coming out from the main breaker box in the house.

Either way, an EV charger would interface with this outlet nicely.