Finally! Full Power in the Shop

[metalmelter2021]

I’ve been using either 120v power in my shop on a 20 amp circuit, or a 20 amp 240v circuit to weld, or once I hooked up my generator with a 30 amp 240v circuit for welding D rings on my trailer. I’ve been trying to figure out how to make some way to keep my full panel box and be able to hook up a full 40 amp circuit, without losing my much needed 20 amp 240v circuits needed for my woodworking equipment.

After discussion with a retired master electrician, he suggested some “piggy back” breakers, also known as “twin breakers to replace the 20 amp 240v circuits, making room for the 40 amp 240 circuit. Worked like a charm! I have all my circuits, including a brand new 5-50p outlet for my welder! Happy day, because I can now use the full power of my Miller 215 if needed. Miller recommends a 40 amp circuit for this machine.

[smithdoor]

Sounds great 👍

Dave

I’ve been using either 120v power in my shop on a 20 amp circuit, or a 20 amp 240v circuit to weld, or once I hooked up my generator with a 30 amp 240v circuit for welding D rings on my trailer. I’ve been trying to figure out how to make some way to keep my full panel box and be able to hook up a full 40 amp circuit, without losing my much needed 20 amp 240v circuits needed for my woodworking equipment.

After discussion with a retired master electrician, he suggested some “piggy back” breakers, also known as “twin breakers to replace the 20 amp 240v circuits, making room for the 40 amp 240 circuit. Worked like a charm! I have all my circuits, including a brand new 5-50p outlet for my welder! Happy day, because I can now use the full power of my Miller 215 if needed. Miller recommends a 40 amp circuit for this machine.

[Oscar]

I’ve been using either 120v power in my shop on a 20 amp circuit, or a 20 amp 240v circuit to weld, or once I hooked up my generator with a 30 amp 240v circuit for welding D rings on my trailer. I’ve been trying to figure out how to make some way to keep my full panel box and be able to hook up a full 40 amp circuit, without losing my much needed 20 amp 240v circuits needed for my woodworking equipment.

After discussion with a retired master electrician, he suggested some “piggy back” breakers, also known as “twin breakers to replace the 20 amp 240v circuits, making room for the 40 amp 240 circuit. Worked like a charm! I have all my circuits, including a brand new 5-50p outlet for my welder! Happy day, because I can now use the full power of my Miller 215 if needed. Miller recommends a 40 amp circuit for this machine.

Oh, so like some "tandem" breakers as they are also called?




Yup, I used a lot of those. I free'd up a LOT of spaces in my sub-panel.

[52 Ford]

I’ve been using either 120v power in my shop on a 20 amp circuit, or a 20 amp 240v circuit to weld, or once I hooked up my generator with a 30 amp 240v circuit for welding D rings on my trailer. I’ve been trying to figure out how to make some way to keep my full panel box and be able to hook up a full 40 amp circuit, without losing my much needed 20 amp 240v circuits needed for my woodworking equipment.

After discussion with a retired master electrician, he suggested some “piggy back” breakers, also known as “twin breakers to replace the 20 amp 240v circuits, making room for the 40 amp 240 circuit. Worked like a charm! I have all my circuits, including a brand new 5-50p outlet for my welder! Happy day, because I can now use the full power of my Miller 215 if needed. Miller recommends a 40 amp circuit for this machine.

Awesome! Having to deal with tripping breakers SUCKS!!!

You NEED to go get some thick steel and run that machine wide open now. Lots of fun to be had!

[52 Ford]

You DID tie the two breakers together for your 40A 240V circuit, right? You don't want one of the 120V legs tripping without the other. It's probably bad for the machine (guess).

[Freebirdwelds]

Congrats and enjoy!

[metalmelter2021]

You DID tie the two breakers together for your 40A 240V circuit, right? You don't want one of the 120V legs tripping without the other. It's probably bad for the machine (guess).

Pics are worth a thousand words...



I'm gonna have have to replace the circuit label here, as some of them have changed, but I will get to that soon. Everything was done according to NEC electrical code and local codes. Everything works just as it should. I did all the wiring in my shop myself.

[danielplace]

You are probably alright but a lot of people that don't know electric burn things up moving single 120 circuits onto tandem/piggyback breakers. Very easy to screw it up and get two sharing a neutral on the same phase if the person didn't understand how shared neutral circuits work. If the circuits are in 3 wire with two hots and one neutral and ground then they are sharing. Also in pipe you have to note what phases they came off and replicate that because without digging into the wiring you would not really know if/which ones were sharing what. You can't just add the tandem breaker and add the other circuit to it and feed both off the same phase to free up a space blindly.

Were any of the 120 volt circuits you moved from the individual breaker sharing a neutral ? As long as they were all using there own neutral you are ok. If any were sharing a neutral then you have to make sure you land the two hots sharing the neutral onto two seperate/different phases. You land them on the same phase and you got problems. Big problems.

It is run with Romex ? Romex on open stud walls is not legal below 7 foot.

[metalmelter2021]

Every individual 20 amp breaker is on its own individual circuit, with its own hot, neutral and ground. The same for each 20 amp double pole breaker, and the 40 amp double pole breaker. This configuation was to simply allow all my circuits to exist in the existing panel box, without having to replace it with a larger panel. Elegant solution.

[danielplace]

Every individual 20 amp breaker is on its own individual circuit, with its own hot, neutral and ground. The same for each 20 amp double pole breaker, and the 40 amp double pole breaker. This configuation was to simply allow all my circuits to exist in the existing panel box, without having to replace it with a larger panel. Elegant solution.

Surely understand why you did it. To free up two more spaces for the new 40 amp 2 pole.

What is the panel fed with ?

Your probably fine in that little panel with relatively small loads but you can't legally just stick tandem or piggy back breakers anywhere you want in any panel to alleviate the problem. There is a reason they only have the amount of circuits they come with and are rated to have in them.

The panel must state it is rated for tandems and how many can be used and in what spaces. Many small panels are not rated for them at all. 8 circuit panel doesn't mean ok to double it up to a 16 circuit.

Just saying to be legal(safe) and everything.

[metalmelter2021]

Surely understand why you did it. To free up two more spaces for the new 40 amp 2 pole.

What is the panel fed with ?

Your probably fine in that little panel with relatively small loads but you can't legally just stick tandem or piggy back breakers anywhere you want in any panel to alleviate the problem. There is a reason they only have the amount of circuits they come with and are rated to have in them.

The panel must state it is rated for tandems and how many can be used and in what spaces. Many small panels are not rated for them at all. 8 circuit panel doesn't mean ok to double it up to a 16 circuit.

Just saying to be legal(safe) and everything.

. The upgrade was discussed with a liscensed master electrician, who was the one who gave me the advice to go this direction, and then again verified at the electrical supply by another liscensed electrician,who saw pictures of the panel, the inside wiring in the panel, and also suggested the same fix for my needs. Both legal and safe! I don’t take chances with electrical.

I’m gonna leave it at that.

[smithdoor]

The thing most forget is if only working in shop you can only use tool at a time. So if you only one 120 v plug and 2 or 3 sizes of 240 v plugs.

Dave

. The upgrade was discussed with a liscensed master electrician, who was the one who gave me the advice to go this direction, and then again verified at the electrical supply by another liscensed electrician,who saw pictures of the panel, the inside wiring in the panel, and also suggested the same fix for my needs. Both legal and safe! I don’t take chances with electrical.

I’m gonna leave it at that.

[danielplace]

. The upgrade was discussed with a liscensed master electrician, who was the one who gave me the advice to go this direction, and then again verified at the electrical supply by another liscensed electrician,who saw pictures of the panel, the inside wiring in the panel, and also suggested the same fix for my needs. Both legal and safe! I don’t take chances with electrical.

I’m gonna leave it at that.

May be legal but you would have to check the panel specs to know which I doubt you did first because you would have simply said ? my panel is rated for tandems, we checked already.

I know it doesn't matter to you and it is working and your going to use it that way just fine.

Personally since we know you can't run all at once it is likely still perfectly safe. LEGAL it may not be. My only point in any of this is to OPEN your eyes and others about the use of these kinds of breakers. It is not a if it fits it works kind of thing.

Just simply informing you that tandems are not always as legal as you seem to think your master electrician said they were and you insist that it is legal. It may not be LEGAL is all I am saying. The exposed romex sure as heck isn't. Lol. Doubt seriously if the tandem breakers are either.

Your the one that keeps mentioning it is legal. Who you talked to first doesn't mean something is legal. While it may be I seriously doubt that panel is rated for tandem breakers.

That panel may have been designed before the code required panels to reject these kind of breakers when they are not allowed but still doesn't make it ok JUST because they fit in yours.

https://www.thespruce.com/tandem-bre...eakers-1152748

https://www.circuitbreakerwholesale....u-need-to-know

https://www.thespruce.com/tandem-breakers-1152736

Was it discussed at all if the panel was specifically rated for tandems ? Probably didn't even discuss the fact the panel may not be rated for them and may not be legal. If the panel does not specifically say they can be used and in what spaces then you can't period, end of story. You would need a panel change or add a sub panel to be legal.

https://www.thespruce.com/tandem-bre...eakers-1152748

Now discuss it with the electrical inspector now. You may find that panel not rated for tandems at all. Romex below 7 feet is surely not legal.

We know your situation is a done deal but maybe the guy reading this will be better informed instead of just doing what you did blindly without regard to the fact if it is correct and LEGAL or not.

[Sberry]

I would be glad to read where romex below 7 ft aint legal? 2nd,,, biggest thing I might question about being legal in this pic is no gfci. But,, this looks good, heck if a guy used box connectors would be well ahead of a lot of installations.

[Sberry]

I am not as familiar with CH but I would be inclined to bet its rated. Limiting the welder outlet 40 wont hurt a thing in todays world. This is a good setup, local control and disconnect is a good thing. Al;so when considering all this is,,, not only wont everything be ran at once but the breaker size isnt the actual load. In a SqD which this isnt the model is a 8/16. That is a basic CH8 I bet but dont recall how they listed it for max spaces.

[Sberry]

In the real world,,, I did a garage punch list after a handyman wired garage a while back. He did some stuff at the building entrance wrong but the rest was pretty good, well stapled and out of the way and I opened a couple boxes and he had connected grounds and wire nutted. I added a gfci, couple other minor details, there was an extension to another building, added a switch to it etc.
But ,,, he used UF, he buried it deep, box connectors (didnt wire panel correct) but about the only place the wire was routed poorly was 1 spot way the fug up and I could see how after the fact it was easy to let it go but of all places the blind owner can find to lean a bunch of scrap lumber up is there,,, sure as sheet, ripped the wire casing.

[Sberry]

There must have been a hundred tucks and turns in this place, 1 bad one and the owner managed to find it.
I was actually glad the guy wired it, really did a decent job. Its tempting for someone like me to start with a box full of breakers and this was a couple utility circuits and room light for storage. It had couple 3 rooms, a freezer, they bought some wire and staples. Looked like work to me.

[Sberry]

I have neighbor has every paper they got on it, has the same 10 cable to his welder he did 40 yrs ago. The man could get any wire they make for free. When I was 20 or 25 would have been in a panic to change it to a 6 but,,, he ran 6 rods last year and knows its all irrelevent when the switch is off. Prolly one of a few left with fuses in garage.

[SlowBlues]

Hard to find (even pre pandemic) and expensive, but these are the business if you are short on circuits (pun intended).

They come in different combinations of amp ratings and are available for most common panel makes and models.

Obligatory disclosure your panel should be rated for tandem breakers.

squareD homeline 20A-120V X 2/50A-240V breaker, model: homt2020250cp

[metalmelter2021]

I would be glad to read where romex below 7 ft aint legal? 2nd,,, biggest thing I might question about being legal in this pic is no gfci. But,, this looks good, heck if a guy used box connectors would be well ahead of a lot of installations.

I used connectors in the outlet box and in the panel as well for the 8/2 with ground copper wire. The master electrician I referred to has personally been inside that panel box on another occasion, before he recommended I use the tandem breakers from Cutler Hammer for this Cutler Hammer panel box. I don't think he would have recommended these tandem breakers if he had any concern whatsoever that it would not be rated for them! Also, at the electric supply [Womack, which is a Cutler Hammer supplier] the electrician I spoke with and showed him pics of the panel, the inside wiring and configuration, said "this is what you need, and we particularly spoke about it being up to code.

I trust these sources, and although not a lisensed electrician, as I did not pursue that as a career, I have indeed purchased and read several books about electrical wiring/circuitry, and have done a fair number of circuit runs from panels in my time. I have pretty much most of the equipment, testers and tools most electricians use, so proper care and diligence was both sought and used for this and other installations I have done. Placement of the outlet is high, but not 7 feet. That was my choice, as it was placed where it was needed.

Inverter equipment does not like GFCI. I have two lathes with them, and GFCI makes them not run correctly or keep shutting down. This is not a wet environment/shop but a totally dry shop.....no need for a GFCI. No water source in this building whatsoever.

[Sberry]

I agree and understand Dianial,,, I am not a fan of tandems either. I have seen some real messes and while we are shop outfitting tend to like my tool circuit on a single breaker. It can go down a couple outlets but there is no replacement for displacement. The 8 spac e panel is what it is for, I think here this is good and practical at this point. Its a hobby garage, not talking hooking unattended heating equipment to it, light work, mostly under user supervision and one of the things of beauty here qand would certainly consider in the hobby diy realm here is to move a couple if I had to and put another 6,,, doesnt even got to go next to it, put it friendly. I used panels, my branches are more like stubs.

[Sberry]

I agree in principle bar, restaurant panel shouldnt be jammed full of twins. Great or ok for attic light circuit, there are a lot of circuits wired in homes never see any load. Me no want laundry, kitchen, heaters etc on a bunch of cheaters. I was in a panel a while back was really crowded and one of the last guys work on it was the real deal. He isnt out to get any extra work but he know the intent of whats legal and had no aversion to using tandems and multi wire etc to work his way out.
The handyman and bud were pretty savvy and the master was gone for some reason and they not quite code know how to realize what the guy had done so to speak.
To his credit,,, the guy is a genius and he used them mostly where was on fixed lights low load, limited time switched off etc.
Number 1 danger in this whole scheme I ever see is circuit extension. I even see the reasoning,,, well,,, I just put 3 new circuits to an addition,,,, problem is the only load was moved while we added room is the tv and whole houses run from chain from 2 or 3 old stuff, even ran across a knob and tube while back, carried half a 3 bedroom house.
One of the most faulty service I see in a while, the N was a strand about number 16 wire at the weatherhead, ownedr looks at me with a straight face standing in front of a mess,,, well so and so says its ok,,, I said, u gonna rent this, would you live over top of it? Doies this even remotely look right?

[Sberry]

I forget I got a camera sometimes. I might have shot a pic of this old fuses with cover laying on the floor. The furnace was a 15 someone had ran new wire back and 3/4 of the place down one circuit with 30 fuse in it and the other 30A to a circuit ran the rest of the place. only reason it didnt burn down was the first 40 ft kt for heat and the extension after the kitchen and bath might have been less loaded but it went all over the place and was simply an extension of one of the original circuits when the building was wired for a light and an outlet. Poor circuit frequently overloaded for decades.

[Sberry]

The gfci are really for 120V equipment, the real end user stuff. The machines and other equipment often plugged in to dedicated so to speak outlets where its easy to insure adequate ground wire size, all kinds of stuff, not such a concern. This panel needs to be fed from the other panel with 4 wire. The 8 2 cable is beautiful for a welder outlet, it dont get any better. You could run 2 modern welders at once from it. You can run a big older machine from it and have used 40 breakers on DC buzzer and 250 feeders.
I got an olkd buzzer and leads I already own but for small garage that might haver a use for a stick the idea of doing it at 20A in for a 1/8 lohy is appealing.

[metalmelter2021]

The gfci are really for 120V equipment, the real end user stuff. The machines and other equipment often plugged in to dedicated so to speak outlets where its easy to insure adequate ground wire size, all kinds of stuff, not such a concern. This panel needs to be fed from the other panel with 4 wire. The 8 2 cable is beautiful for a welder outlet, it dont get any better. You could run 2 modern welders at once from it. You can run a big older machine from it and have used 40 breakers on DC buzzer and 250 feeders.
I got an olkd buzzer and leads I already own but for small garage that might haver a use for a stick the idea of doing it at 20A in for a 1/8 lohy is appealing.

The small shop panel is fed with 4 wire 4 gauge from the house. Geez, I surely wasn't expecting such a anal exam for doing the right thing. I realize some are trying to be helpful, and probably the average Joe could make some serious mistakes with wiring because they do not have knowledge of amps and draw, etc, but I do, and have some professional backup any time its needed. This panel and circuits from it are the end of the run, being an out building. This will never have an addition added, nor circuits added to this panel from here on. This is safe, up to code according to the two licensed electrician I ran it by, one actually being inside the panel and knows what is in there, and the other seeing up close pics of all the wiring, neutral bar, ground bar, etc, so as far as I'm concerned, due diligence was exercised to not overload anything, and well within established parameters.