Adding 220 to my sub-panel?

[Titus]

The prior owner installed this 60A sub-panel in the shop:

The 15 Amp breaker is wired to 6 wall outlets. Current loads include a bendpak lift and a dehumidifier.

The first 20 Amp breaker goes through a wall switch to 4 outlets on the ceiling that I am using for lighting (8 4' T8 bulbs, likely will add another 8 soon.

The second 20 Amp breaker goes to 10 wall outlets. Current loads include 20 gallon compressor, parts washer, bench grinder, 70's pinball machine, and power tools.

I would like to add 2 220v outlets to the shop for a welder and a larger compressor. I also plan on adding a window A/C unit that could be 110 or
220... not sure.

Can my current sub-panel be re-configured to handle my plans, or do I have a more extensive/expensive wiring job ahead of me?

 

[mrb]

as far as whether you can cram enough breakers in there for what you want to add, you can get two 20a 240v circuits, and two addtional 20a 120v circuits.

Remove the two existing single pole 20a breakers. Install four QOT2020 breakers in the two empty slots plus the spaces from the two breakers you removed. Then install a QOTHT handle tie between the center breakers on each pair so that it looks like this A A---B B where the '---' is the handle tie, AA is the first breaker and BB is the second breaker. One pair of non handle tied breakers will replace the two 20a ones you removed and the other pair gives you two more 120v 20a circuits.

If you need a larger 240v circuit, you can do one pair of what I mentioned above for either two additional 120v circuits or one new 20a 240v circuit, then in the two empty spaces you can put a larger 2 pole breaker. Make sure you dont overload the 60a feed to your panel.

When you have the panel open, check to see that the neutrals and grounds are properly isolated, thats often a problem in garage panels that 'the last guy put in'

 

[PAToyota]

First question is whether you have 220V to the subpanel? Are there two hots or just one coming into the panel?

 

[Titus]

First question is whether you have 220V to the subpanel? Are there two hots or just one coming into the panel?

Here is a shot of the inside of the panel.

 

[mrb]

you do have 240 to the subpanel, and the neutral and ground are properly isolated. There are a couple minor issues in there, but generally speaking it looks ok.

 

[PAToyota]

Yep, just thought I'd ask. I've seen 110V run to subpanels before - which is kinda stupid even if you're only using 110V because it is harder to balance the load.

As to your original question, depending on loads you are going to overload things quickly if you're trying to run either the welder or compressor along with lights and a/c or some such combination. But you could likely make it work knowing that you cannot have more than one - a/c, welder, compressor - on at a time and keep 110V loads (lights, radio, such) to a minimum while using one of the 220V appliances.

For reference, the circuit I run my MM250X on is 50amp just on its own and the TIG is on a 100amp circuit.

 

[Titus]

As to your original question, depending on loads you are going to overload things quickly if you're trying to run either the welder or compressor along with lights and a/c or some such combination. But you could likely make it work knowing that you cannot have more than one - a/c, welder, compressor - on at a time and keep 110V loads (lights, radio, such) to a minimum while using one of the 220V appliances.

I have no problem shutting off the A/C and Compressor before welding, and was even thinking it might be best having only one 220v plug that would force me to unplug the compressor prior to plugging in the welder. I think I would have less control of the A/C and compressor being used at the same time. I am hoping that won't be a problem, as I am planning on a 3.2 hp 60 gallon compressor which shouldn't be as huge of a load as some compressors.

If I was too try not to push it and increase the service to the panel, what would need to be replaced? Is the wiring to the sub panel sized to 60 amps, or could it handle more?


* Note- for those getting concerned that I might try to do this on my own while asking very elementary questions, don't worry... I am going to hire someone. I just want to get a good idea of what is possible, what my options are, and how much coin I will need to spend before making an electrician make the 30-40 mile round-trip out to my house.

 

[PAToyota]

Those feeder "cables" don't look all that big. I'm guessing that they are the minimum required for 60amp. How far away is the main panel and what size is it? Remember that you are paying an electrician for electrician's wages no matter what he is doing. Ask him if you'd be able to pull the wire yourself and what size - then have a wire pulled from the main panel to the subpanel when he shows up and he can make the connections.

 

[Titus]

Those feeder "cables" don't look all that big. I'm guessing that they are the minimum required for 60amp. How far away is the main panel and what size is it? Remember that you are paying an electrician for electrician's wages no matter what he is doing. Ask him if you'd be able to pull the wire yourself and what size - then have a wire pulled from the main panel to the subpanel when he shows up and he can make the connections.

It looks like 1" PVC through the wall of the house garage (by the main panel), a 20 foot run of 2" PVC under ground to the shop, and 1" PVC through the wall of the shop (by the sub panel).

 

[Tom2]

My sub panel is similar. (Square D - same size)Like yours, you probaly wouldnt want to run a welder the same time as water heater, etc on the subpanel. I just keep the welder breaker shut off. If I ever want to use it, I'll kill the other breakers first.
Just to keep from tripping anything.

 

[sberry]

Just to add, this really depends on the welding machine and its use but he wont overload this 60A service in a small garage. He would really have to work at it and the worst outcome would be to trip the main with a comp start while welding with all the lights on, the nature of this load wont overheat the wire.
I am sure there are cases but I cant recall,,, ever of having overloaded service on a small garage with a one man show that was 60A or better. My Bud run a mechanic shop in one for 25 years with a 60A feed. I can remember farm equipment poorly distributed running from 60A service and fuses in the day, occasionally a blown fuse from lopsided deals but with modern breakers and several circuits never, never a problem.
I think in this case the service is fairly close, a plus and if it was mine a sub would be placed strategic to gain some panel spaces, fed from the main lugs of that panel. Add 2 240 circuits and 2 120 outlets.

 

[Charles (in GA)]

When using a backfed breaker for a main, like the one in the Original Posters panel, it needs to have an approved screw or retention device to thwart its easy removal from the panel. Required by the code. I do not see one in the pics. Home Depot or Lowes or your local electric supply will have them.

Charles

 

[2LTim]

It doesn't cost anything to trip breakers, just an annoyance! You could add the additional breakers and circuits to your existing panel and try it. If tripped breakers getts to be too bothersome, you will already have the breakers you need, just upgrade the panel and wiring from the main.