I think I know the answer to this but I'm not a licensed electrician so sometimes the obscurities of the NEC escape me...

I have a GE panel in my attached garage (owned this house less than a year) and recently while trying to wire in a timer for the pool-pump I discovered some hack-job wiring. Not only do I need to convert my 110 pool pump circuit to 220, but I need to un-screw some stuff somebody else screwed. BLUF, I need more panel space because I have to add 2 more 220 circuits in place of a single 110 circuit.

The entire left side of my panel is these massive breakers, 1 50-amp branch circuit for the previous owner's ham-radios, 2 for the furnace, and 1 for the dryer. 3 of them are 30-amp.


The right side is almost all 110 circuits except for two 220 circuits using this style breaker.


As long as the breaker is placed to properly hit both lines, is there any reason I cannot replace 2 of the 30amp breakers of the first style, with four of the 220 amp breakers of the 2nd style (30-amp and below)? I understand that the 2nd style breakers likely don't go over 30-amp, but that is a non-issue for me as I'm not trying to add more high-amperage circuits.

No.


Why not just delete the old ham radio breakers? That's four circuits freed up right there.

You can't do what you're describing.

The first breaker you show is a 2-pole breaker. It can provide 220V because it is connected to both legs of the service. You see 220V between the lines because one leg will be 110V when the other is -110V and vice versa. You can also use this type of breaker to supply a multi-wire branch circuit at 110V.

The second breaker you show is a single-pole tandem breaker. It can only supply 110V since it is only connected to one leg of the service.

220V breakers must trip both legs simultaneously.

Depending on the panel they go into, it might be doable. Need pic of the label in the panel with the model number. You might have a 20/30 or 20/40 or 30/40 panel 

4 circuits? How do you figure that? There is a single 50-amp breaker of the first style. Even if I delete that (which I really don't want to do) it only frees up space for a single 220 circuit if I have to use the first style breaker in it's place, or two 220 circuits if I can use the 2nd style breaker. Which is why I'm asking. I would rather leave that 50-amp 220 circuit because 220 outlets are handy to have when you need them.



I fully understand the electrical functions, the 2 different legs etc. Just not sure if there is some obscure reason they would have used both of the above style breakers in my panel for various 220 circuits and why one was chosen over the other.

The 2nd breaker pictured may, in fact, be a single pole tandem breaker (I just snagged a pic from google), but there are breakers like that in my panel (on the right side) with a tie-bar between the 2 poles that are supplying 220. Can this not be done if there is a tie-bar connecting both sides of the "tandem" breaker together so they both simultaneously trip and it is placed so that it connects each pole to different legs? ETA, I just noticed the MWBC comments; if the 2nd style can be used to supply a MWBC why can't it supply a 220 load? A MWBC is basically a 220 load that shares a common neutral. You CANNOT power both hots of a MWBC from the same line. They have to be the 2 different lines (which combined will create 220), and you have to use a tie-bar on the breaker to ensure simultaneous tripping. How does that vary from a 220 load with or without a neutral? The breaker is the same and serves the same function...

I already pulled one of the 220 breakers of that narrow style and verified that they're hitting 2 different legs on the panel and they are. That was one of my first steps to verify that this could physically be done.

I'm mostly wondering if there is some obscure NEC reason why the fat/wide breakers were used in-lieu of the narrow style for the other 30-amp 220 circuits. Why mix & match?


FWIW, in regards to both legs tripping at the same time, one of the issues I'm trying to fix is a 220 circuit (not sure where it goes, but I think it may be for the hot-tub) that is currently connected to 2 different single-pole breakers; 1 wire on a dedicated breaker, the other piggy-backed onto another single-pole breaker 7 spaces away. That is F'ed up; not only unacceptable, but down-right dangerous. I'm trying to fix this issue correctly.

my mistake I misremembered what your OP was. For some reason I thought you said there were 2 two pole breakers.

You'd just be reusing the breaker. Everything else would still be in place so if you needed that 220 outlet for some reason you could just swap the wires on the breaker.

You can condense single pole breakers onto the tandem, too.


If you know enough about what you're doing, or have the money, the best answer is to just get a larger panel, or to run a subpanel.

Just so I know I've got terminology right in regards to tandem.

I know that you can get the special "2 breakers in a single slot" for crowded panels. That is what I always referred to as a tandem. Those are the really expensive ones intended for crowded panels.

The panel I have is a GE and will accept 3 different types/sizes of breaker. It will accept the 1st breaker pictured, a double-pole, 2" wide breaker. It will accept the 2nd pictured, which can function as a 1" wide tandem, or a 1" wide double-pole depending on where you stick it on the bus and if it has a tie-bar. The final breaker is a single-pole 1/2" wide breaker that would effectively be half of the 2nd breaker above. I'm not sure if a 1/2" wide true tandem breaker intended for overcrowded panels is available. The 3 regular breakers are all normal breakers, easily obtained at the big-box store for cheap money. So is a "tandem" any 2 breakers in a single unit being used on only 1 line/side of the AC?

What I'm trying to figure out is why would the installer have chosen the 2" wide 2-pole breakers over the 1" wide 2-pole breakers? Is it an NEC consideration? Were they trying to fill all the spaces in the panel? I know that larger amperage breakers are only available in the 2" wide format, but the 30-amp and below are available in the 1" format as well, I have some of those already in this panel. Does this make more sense?

This is already a sub-panel. I'm not sure if you can put a sub-panel on a sub-panel but I don't really want to. The house already has 3 sub-panels (this one in the garage, and 2 next to the main panel)

Further research indicates that I have GE THQ style breakers, which are available in both a 1" (THQL) format and 1/2" (THQP) format to be installed in the same panel. I can get THQL breakers that take up 1" per pole in both single pole and double-pole, and I can get THQP breakers that take up 1/2" per pole in both single-pole & double-pole. The breaker in the 2nd picture in my op is either a THQL tandem (no common trip bar), or a THQP double-pole (common trip bar). Considering that the GE catalog doesn't make mention of a THQL tandem as being available I'm inclined to believe the above a double-pole THQP breaker, which is what I desire to put in place of some double-pole THQL breakers.

There is an NEC consideration in regards to the maximum number of circuits my panel is rated for. I will verify that info when I get home and develop my plan of attack from there. Going over the breaker arrangement in my head (there are 5 total of the THQL 2-pole on the left half and no others) it's a 40-space panel (1/2" breakers) with 10 1" spaces and 20 1/2" spaces occupied. I suspect it's a TLM2020CCU based on looking that their catalog, which permits up to 40 single-pole circuits, so it's a non-issue to swap THQP 2-poles in place of the THQL 2-poles, I just have to offset the THQP breakers 1/2" so that I get 220 instead of 2-lines of the same voltage. I'll just swap a couple single-poles over to the left side of my panel and start swapping in breakers.

The old breaker limit was removed some years ago.

The limit now is the 'listing' of the panel.

What is the point you're trying to make?

There is still a breaker limit, but it's no longer a simple calculation, it's based upon each panel and it's respective listing. If the panel I have is the model I referenced above, it's listing permits more breakers so it's a non-issue.

OP, whatever we say, you'll tell us it's wrong, ask 7 supporting questions in wild detail even the manufacturers engineers might wince at, or explain in detail what's really going on.

Sound right?

I'm not sure what you're getting at.

Are you trying to allude to the fact I've done something akin to this in the past? Are you trying to say I've done it already in this thread?

I think the only person that is wrong in this thread is rjbergen and I think that's only because he wasn't following that this GE panel has 2 different size-format breakers available. What I know is a 2-pole breaker, he mistook as a tandem breaker and based his response on that. No fault there, I should have provided panel and breaker part numbers in the OP to avoid that confusion. Everybody else has provided good information that has helped me discover what is going on and what I need to do... well, everybody except you and brickeye, it seems he always shows up late to the party, tells people what they already knew, then acts like God's gift to man for providing his profound knowledge.

So what is it that you're getting at?

How big is your service and how many spaces is your Main Service Panel?

The old limit of 42 breakers per panel is removed.

The only limit is how many slots and what the manufacturer tested to.

They used to stop at 42, and in many cases smaller panels had physical hardware to prevent the installation of more than 42.

Yeah, no.

You see 220v because you get 220v. If one leg is +110 and the other is -110 your net is zero. A single leg oscillates from 110 to -110 yes, but BOTH legs oscillate from 220 to -220. Hence why no neutral at the transformer required for 220. The other line IS the "neutral".

[quo ptive.

I did some more digging and what I thought was a sub-panel in the garage may not actually be a sub-panel. I thought it was a sub because it's a main-lug panel, not a main-breaker. But the main panel for the house doesn't have any breakers that disconnect it. I think the power comes in through the meter, splits to 2 different main-disconnects on the outside of the house, one goes to the main panel in the house (that feeds the 2 subs next to it) and the other 200A disconnect feeds the garage panel. Seems odd to do it that way; if I need to shut down the entire panel in the garage I have to go outside and walk all the way around to the other side of the house to shut the service disconnect off.

At least that panel is a convertible panel (I can convert it to main-breaker if I want to).

So to answer your question, I guess I have 2 separate 200 amp services coming from the same meter. I'm not sure if the total service is 400 amp or 200 amp. I also have a separate 200 amp service for the shop (1/4 mi away) as well but that's largely irrelevant to this discussion...