Wiring questions

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Capt. Jas.

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Hello and first post.
I currently have in my shop a breaker box (coming off my house service) containing 4 20 amp breakers for my lights and 110 receptacles along with a 30 amp breaker that is currently being used for one 220 outlet using a 10/2 wire. With that, my box is full.

I have just acquired a mill/drill that is single phase 220 and a lathe that is 3 phase 1 hp.

I would like to be able to use that 30 amp breaker to run an 8/3 line to my phase converter (manufacturer reccomended size) and also have a receptacle from same to run my single phase 220 mill.
The 220 receptacle on the 10/2 I have now will be eliminated.
What are my options, if any?
Thanks
 
I think it will work just fine, since you won't likely be running both machines simultaneously you should have plenty of current
it may even be enough for a small welder
mark
 
If it is available for your breaker panel (and OK with your local electrical codes), you may be able to replace the 4 x 20A breakers with half-width single pole breakers. That will open up two full spaces for a two pole breaker for another 220V load.
 
The latter reply is the most viable. I would advise the use of such double breakers on the 120 volt circuits to open up the bus bars for a 2 pole/220 volt breaker. They are called "piggy back" breakers at the supply house.

An alternative would be to use the piggy back breakers next to each other to provide the needed 220 volt supply. This is a much less desirable solution that would depend on local electrical codes to implement.

If you wanted to pursue the matter deeper, may I suggest
from a perspective written specifically for Home Shop Machinists. I did leave off some of the more detailed information toward the end, mostly to avoid liability on the site when it was commercial. The business about double piggy backs is covered there.
Bill Hudson​
 
Thank you gentlemen for the responses. Here is a picture of the box in my garage. It certainly would be really helpful to be able to double up on the 110 as mentioned and allow room for one breaker as dedicated to the RTP and then I could keep the 220 receptacle I have and run another new one with it for the single phase mill/drill.
 

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Glad to see the box is a SqD. One I am quite familiar with, albeit a few years back. But then, so's the box. We're both antiques, although the box not so much as me. Is there an emotocon with a long grey beard and a silly grin?

The piggyback breakers should be available at Home Depot or Lowes, whichever is more convenient for you. Replacing all four breakers would provide two double pole circuits. I would recommend they be limited to 20 Amps each. That for the size of the bus bars in the boz and the size of the feed. Only using one at a time shouldn't overload anything. But you need to be sure it's only one at a time. And most importantly, using something to tie the two toggles together to provide for a "common trip" arrangement.
 
We have larger series same line panel.

They have many "interesting" breakers.

Consider 4 1/2 size breakers bonded together.

Some have "cross bar" devices that connect just inside 2, or out side 2. Or one on the outside and one on the inside

Most have the center 2 connected for 240 vac operation and outside not bonded for 120 vac operation.

We have one that is 20-30-30-20, outside are independent 120 vac and center is 30 amp 240

For a home shop you likely will not run multiple high loads but proper planning.

Compressor or other self starting device needs to be away from other high loads.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
Say, I just learned something. Don't happen often :)

My house load center is clear full. Its a 25 year old square D. Can piggy back breakers be used here to free up space for another 220 circuit or two?
 
Karl_T said:
Say, I just learned something. Don't happen often :)

My house load center is clear full. Its a 25 year old square D. Can piggy back breakers be used here to free up space for another 220 circuit or two?
Click to expand...
Yes
 
Range and dryer breakers are good to replace with the 4 x units.

Lighting also good with doubles, standard breaker size but 2 units inside.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
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