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Bozeman, MT

[Electrical] How do you set up a breaker box?

How do you decide what locations breakers go to in a box? Do you care?

Range, dryer, water pump are double breakers. Do they go in a line down one side or jammed together at the top or bottom or split up.

Is there any rhyme and reason to what goes where?

I have seen panels that just seemed to be layed out very well and I have others that I have to turn off nearly every breaker to find what I need off. It isn't completely tied to just having labels on stuff.


Lawrenceville, GA

[Electrical] Re: How do you set up a breaker box?

It doesn't matter where in a panel a breaker goes.

Premium,ExMod 2000-03
NW Illinois

1 recommendation

reply to ttiiggy

There is no *right* answer to that question. It depends on personal preferences of the installer, the number of circuits involved, where the cables will enter the box, how many other breakers are in the box, etc.

Some guys (gals included) like to place them at the top, some at the bottom, some after all the other breakers are in, and it goes on and on.

As far as your comment about being laid out well and others that require you to "turn off nearly every breaker", I'm not sure what that means. Regardless of the breaker layout, if they are properly identified as to what rooms/circuits/devices they protect, its all the same.

Louisville, KY
reply to ttiiggy

Re: [Electrical] How do you set up a breaker box?

While there is certainly no right or wrong answer to where the breakers go it seems like every panel I've seen that was laid out neatly at all of the double breakers (240 V) at the top and then the single pole breakers below them leaving any empty space at the bottom for future use.

Sunnyvale, CA
There definitely are panels where not all slots are equal (such as permitting high current breakers only in the upper positions and half-width / tandem breakers only in the lower positions). Restrictions on breaker types for certain slots are normally documented in/on the panel itself. Just because a particular breaker mechanically fits into a certain position does not mean that this is an approved use of the panel.

Since there is so much variety it is important to follow the instructions for the specific panel you are dealing with.

If it is a new install of a panel that does have usage restrictions on certain slots it is generally a good idea to keep future expansion in mind. This can mean to keep some of the most versatile slots (those with the least usage restrictions) free or it can mean to keep some slots of each type free. Otherwise when adding circuits to an existing panel (following the usage restrictions for the panel) it can result in having to shuffle several breakers to different positions.

Even a residential main panel that has only one type of slots (the same list of breakers is approved for all positions) may still have exactly one position where a backfeed dual pole breaker can be installed (together with a lockout kit) for generator hookup. In such a panel that backfeed breaker position (despite often being at the top) would be a good candidate to leave free until such time that either all other slots are full or a generator hookup is installed.
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Mr Matt

Eustis, FL
·Embarq Now Centu..
reply to ttiiggy
said by ttiiggy:

How do you decide what locations breakers go to in a box? Do you care?

First, depending on who manufactured the panel the maximum number of single circuit breakers and double (twin) circuit breakers will be stated on the label. Some manufactures limit twin breakers to the lower half of the panel by notching the stabs. Twin breakers cannot be inserted in the stab where it is not notched. Always insert single circuit breakers in the single circuit breaker stab slots first. That is the reason you will see high current circuit breakers for AC Condensers, Air Handlers with heat strips and Electric Range, to the top of the panel. Current breakers 30 Amp and lower are available in twin configuration. Breakers serving 220 Volt Loads must be installed so that each breaker is plugged into an adjacent stab. There are twin breakers for 220 Volt Circuits, like dual 30 amp breakers with linking handles. I have one dual 30 Amp twin breakers that serve the dryer and water heater. Always install single full width circuit breakers in single breaker stabs first.

LXI 483
O Fallon, MO

2 recommendations

reply to ttiiggy
With the advent of major AFCI requirements, it takes a little more planning to lay out a panel. Most of the municipalities I service have started enforcing the AFCI requirements of 2008, 11, or 14.
It's getting to the point where nearly 1/2 (or more) of the branch circuit breakers in the panel are AFCI (and GFCI). AFCI and GFCI breakers have a problem: They produce their own heat, in addition to the coil heat normally generated by a circuit breaker.
As a result, a phenomenon known as "heat rise" occurs. Heat rise can cause nuisance tripping on heavily loaded (but not overloaded) circuit. Circuit breakers trip two ways - heat (thermally) and magnetically. A thermal trip usually occurs on a circuit which is slightly overloaded for an extended period of time. A magnetic trip normally occurs on a circuit that is heavily overloaded or shorted.
The additional "heat" generated by the AFCI / GFCI circuit adds to the "natural" coil heat of the breaker.

Some AFCI manufacturers talked about skipping the solenoid and using the microprocessor for overcurrent protection, but as far as I can tell, none of them have implemented this. I equate it to replacing the throttle cable in automobiles with "drive by wire" technology.

I have experienced this "heat rise" nuisance tripping first hand. I contacted a manufacturer rep and their response was to not stack more than 2 AFCI / GFCI breakers in a row. That was fine and dandy when code only required AFCI breakers in the bedrooms.
It's a little different now. The last house I did required 18 AFCI breakers in one panel.

I still lay out a panel to try and not have more than 2 AFCI breakers in a row, but it is difficult. I also don't want all of my branch circuits loaded up on the same 1/2 of the phase (every other).

Certain panels are still not conducive to AFCI installation because of their neutral bar layout (Square D and Cutler-Hammer BR come to mind).

I try and put the larger conductors at the top to keep the wiring trough from being congested all the way down.

On a panel replacement, it's every man for himself. I lay out the conductors by length and install the breakers accordingly to avoid splices in the panel.
If someone refers to herself / himself as a "guru", they probably aren't.

Caveat Emptor
United State
·TracFone Wireless
reply to ttiiggy
I always thank god for real electricians. I bought a house with over loaded circuits. The local guy said the owner did not want to pay for a new panel, so he did. "Triple tap" the real electrician called it. I had a second panel installed and had the mess separated and on new breakers. Then I discovered the water pressure tank is on a penny fuse. It is on its own circuit. I have it checked yearly. When it blows it goes; it will be moved to the new panel.
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Streamwood, IL
reply to ttiiggy
If the manufacturer of your panel makes a generator lockout for your breaker panel, and you might want to install one some day, consider leaving the top 2 rows under the main breaker empty.


Welland, ON
reply to nunya
said by nunya:

They produce their own heat, in addition to the coil heat normally generated by a circuit breaker.

That's good to know. I've been slowly upgrading the wiring in my house. I still have to upgrade the wiring in my living room and bedrooms, which will require AFCI.

Though I'm running out of spaces in my panel. Still considering either a bigger panel, or maybe a sub-panel.

Queens, NY

1 edit
reply to ttiiggy
Generally, the rules for laying out panelboards (which could be applied to a residential load center if one is extreme) are as follows:

1. Follow the instructions. Some panels have restrictions on what breakers can be placed in which slots.
2. Breakers with more poles go at the top (assuming its a top-fed panel. Reverse everything here for bottom fed.) Balance them out with the same number of breakers on each side of the bus (to the degree possible).
3. Breakers with higher (amp) ratings go at the top within the group of breakers with the same number of poles. Balance them out on each side of the bus, again to the degree possible.
4. Balance the load on each phase (or each pole for 240V single-phase residential) to within 10% on each bus, or to the degree feasible. To do so requires accurate load calculations for each branch circuit & feeder. Balancing is done by swapping breakers from the above layout until you are within 10%. This takes some experience/ understanding.

Happy you've asked?

So, a typical layout from top to bottom could be:

1. (1) 50A 2-pole range breaker, upper left.
2. (3) 30A 2-pole appliance breakers (2 on right, 1 on left below the range breaker)
3. (2) 20A 2-pole appliance breakers (one left, one right).
4. (12) 20A 1-pole breakers (half on each side)
5. (12) 15A 1-pole breakers (half on each side)

Then you would proceed to balance the panel so the loads on each bus are within 10% if possible. As well, consider any other concerns, such as heat concerns with AFCI breakers that nunya discussed above.