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My panel is a GE TX1612RH split-buss 125A panel (photo below). It is an outdoor panel, vintage 1980 when home was built. I want to run two 20A circuits to a shed 60-ft away and would like to know if the following changes are advisable and in accordance with Code: 1) Move the 2-pole 30A (thin) breaker for A/C to the slot immediately above the 50A "Sub-Main" breaker, thereby consolidating all 240V loads in upper portion (I think the A/C contractor goofed on the electrical portion); 2) Install a 20A "thin" breaker in lower-left slot for a dedicated circuit for an in-wall 120V shed heater (blank-face GFCI will be upstream of in-wall heater); and 3) Install a "full-width" 20A GFCI/AFCI breaker for everything else in the shed, using the slots formerly used by the 2-pole 30A breaker. Regarding #1: Is it OK to use "thin" breakers in the upper buss, or should I replace the 30A thin breakers with the full-width variety. Many thanks!

Update #1: Photo of panel interior has been added. Unfortunately, there are no placards or labels on inside of panel door or on back side of cover, so I'm driving "blind." Googling the "K849 *" reference (top of back of panel), I found nothing.

Update #2: The A/C contractor (in 2008) used very MINIMAL wire to reach the 2-pole compact 30A breaker -- not enough wire to extend to the new and proper position of a full-width 2-pole 30A breaker above the existing 2-pole 50A breaker. Any suggestions for a remedying this dilemma? Rules for using red-head connectors wrapped in rubber and vinyl electrical tape? Or must I pull a new run of #10 copper conductors?

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    Can you post a photo of the labeling on the inside of your panel's door please? – ThreePhaseEel Aug 9 at 2:55
  • My panel is a similar GE split bus with 150 A service. If you want to reopen this post, I will give an answer. In my panel the ac is powered by a full sized 2 inch wide 40 A breaker in the upper section. – Jim Stewart Aug 9 at 4:18
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    Yes, and the Eel is looking for the data label that includes model number, screw torques, accessories, and a diagram of the panel layout. – Harper - Reinstate Monica Aug 9 at 4:26
  • How are you running two 120V circuits to a shed without violating NEC 225.30? Will one of them be on a switch? – Harper - Reinstate Monica Aug 9 at 16:49
  • Thanks. I don't have the NEC text (I presume you have to purchase) but thought I could run separate neutrals for the 2 circuits (one dedicated, and one shared). Now I know better. What kind of switch would make a 2nd circuit legal? Would I need a subpanel for both circuits inside the shed? – Marty Aug 9 at 17:30
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In my very similar GE panel the sticker diagram indicates that the upper section will NOT accept compact 2-pole breakers (1 inch wide) on the right side, but will accept them on the left side.

The simplest way to connect your ac in the upper section would be to use a full sized 30A 2-pole breaker in the upper right. These are very cheap, but you would have to work on the panel hot. I have changed breakers in the lower section of my panel without switching off the 60 A main breaker, but the upper section presents greatly increased risk if you would make a mistake or if the breaker was defective in a certain way (shorted internally) which I must assume never occurs in practice.

The diagram on the sticker in my panel shows that compact 2-pole breakers MUST be inserted in a way not immediately obvious to an inexperienced person, but clearly correct when you think about it. The compact 2-pole breaker must be ASTRIDE (bridging) two full slots. It cannot be placed in one full slot. It will not snap in and it would not work there because both contacts in a full slot are on the same leg.

In my panel if I wanted to increase the number of 2-pole breakers in the upper section from four to five, then the two full sized 2-pole breakers on the left would be removed and three compact breakers put in their place.

Note the compact 2-pole breakers will snap in ONLY astride two (full) slots and can only work if they are astride two full slots. Starting at the top left the top half slot (1/2 inch)is left open, then the three compact 2-pole breakers are placed, then the bottom half slot is left open.

Note that in your panel the compact 30 A 2-pole breaker in the lower section is astride two full (1 inch wide) slots. If you ever move it, it must be inserted that way.

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This is a split bus aka rule-of-six panel. They were originally developed because breakers over 60A were cost prohibitive (no longer true). They are outlawed now, and are dangerous because nothing prevents you from overloading the service.

They were allowed when a load calculation was done that showed the house would not overload the service; however, when people add circuits they don't bother to do another load calculation, and that's the danger. Normally a large load like the A/C would be put in the Rule of Six area; putting it in the Lighting area makes me wonder if they did a load calc and it went badly. Any idea what came out of that space?

GE and their double-stuff rejection system

GE has a funny way of doing double-stuff breakers. All their bus stabs look like normal bus stabs, a flat horizontal blade maybe 3/8" to 1/2" wide. However, on spaces enabled for double-stuff breakers, they have a vertical rod - I call it a "cruciform" for the way it crosses the bus stab. The double-stuff (1/2" wide single and 1" wide 2-pole) clip onto this cruciform.

In 1966 NEC added "CTL" rules limiting the number of double-stuffs in a panel. They required mechanical keying to reject double-stuffs where not allowed, so most builders notched their bus-bars and came out with "CTL" breakers which would reject in a normal space. (as well as non-CTL breakers to support pre-1966 panels, haha, guess what everyone did). GE simply omits the cruciform. Which means, there's no way to trick a double-stuff where GE doesn't allow it.

In a split-bus aka "Rule of Six" panel, there can only be six breaker throws to de-energize the whole panel. So there would be no earthly reason for GE to install the double-stuff-enabling cruciform in those spaces.

Now, this panel only supports four full-size 2-pole breakers in the "Rule of Six" section. You might think GE intends you to use three 1" wide 2-pole breakers per side. Looking closely, it appears the cruciforms are in exactly the right place to support just that - note there is no cruciform on the top half of the top space, so you can't put a 1/2" wide 1-pole there. You'd have to leave that empty.

You can't run 2 120V circuits out to a shed, anyway

Rule 225.30 says you can only run one circuit to an outbuilding. The rule intends that be a feeder to a subpanel. However, there are certain exceptions:

  • A different-voltage circuit is OK, and this is where I'll introduce you to the multi-wire branch circuit. This is a 120/240V circuit with 120V loads placed between one of the two hots and the shared neutral. You can also power 240V loads between the two hots (but the breaker must be 2-pole if you do that).
  • If one of the circuits is switched from the supply end, then it's OK. So if you are hellbound and determined to have 2 independent circuits, find a believable pretense to put a switch on one. (e.g. so you don't have to put your shoes back on to switch off the forgotten shed lights).

Breaker strategies

One option is to get a full-size 2-pole 30A breaker, place it in the open position, and use it for the A/C. This will require extending the A/C cables, but you can do that with normal (well, large red or tan) wire nuts.

That frees up the 2 double-stuff spaces for 2 thin breakers (or a 20A 2-pole for an MWBC).

Another option is just get two full-size 1-pole 20A breakers and put them in the Rule of Six area and use them for your new circuits. You still only have five throws to turn everything off, so that's legit. Nowhere is it written that circuits in the Rule of Six area must be 240V.

  • You could also get one 1/2" and one full-size breaker in that Rule of Six area, if that matches the current knockouts that are removed from the panel cover.

  • For that matter, you could put three 1/2" breakers in the Rule of Six area, because that will be only six throws. Keep in mind for future, heh, expansion in this very full and obsolete/dangerous panel.

Any now-empty breaker knockouts need to be filled with a blanking plate - you can't have curious fingers finding bus bars. I find those blanking plates to be expensive, hard to find and very flimsy - so I prefer to arrange panels so all holes are full of real breakers. Which are not flimsy.

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  • Monica: Thank you! If I understand the above, I could LEGALLY run two 20A 120V circuits to my shed, provided I feed them with two full-size 1-pole 20A (GFCI/AFCI) breakers in my Rule of Six Area. If so, I'd leave my 2-pole 30A breaker for A/C where it's at and run five #12's (2 hots, 2 neutrals, and a ground wire) in 1/2" rigid conduit to a weatherproof receptacle on the outside of my shed, then go from there. I would also have a 20A single-pole switch on the dedicated circuit (for powering the heater on/off) but INSIDE the shed. Heater is hard-wired; has a thermostat but no on/off switch. – Marty Aug 9 at 19:52
  • But as I wrote my panel GE TX1615F FLUSH MOUNT 150 AMPERE the sticker indicates the left side will accept three compact 2-pole breakers and would leave two open 1/2 inch spaces. If the bus bar is the right shape then could it be that a 1-pole 20 A breaker would fit there to go to the shed? Or is the shape of the bus bar connection designed to exclude placing a 1-pole 1/2 inch breaker in the top and bottom? Right now I don't want to pull a breaker and see. Only one half slot could be filled to satisfy the rule of six. – Jim Stewart Aug 9 at 21:03
  • In my case only one open half slot could be filled to satisfy the rule of six. Right now my my upper section if filled with four full size 2-pole breakers: 30 A, 40 A, 50 A, 60 A for dryer, a/c, range, main, respectively. I could replace the 50 A with a 40 A for our current range. – Jim Stewart Aug 9 at 21:14
  • @Marty you're right on track, EXCEPT the switch must be at the house. See my two exceptions to 225.30. – Harper - Reinstate Monica Aug 10 at 2:13
  • OK, thanks, Harper. I misinterpreted your "breaker" comments --thought putting the two 1-pole 20A breakers in the Rule-of-Six area would qualify both as "switches at the supply end." The panel is outdoors on my patio and 60' from the shed, so the best place for the switch would be on the patio next to the panel. Will give consideration to a Plan B: a subpanel in the shed, an MWBC, a main lug panel, or dropping the in-wall heater which would obviate the need for a dedicated circuit. – Marty Aug 10 at 5:09

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