Breaker numbering in panel.

[Gtsco12]

Mike while working on a job a twin 20 amp single pole breaker was used in place of a full size breaker in order to add an additional circuit . All spaces were being utilized. I was told I needed to re number the panel to identify the breaker in it's space. Example: breaker slot #4 would become #4and#6 My argument was you are not allowed by UL standard to change the number orientation of the manufacturer stamped numbering system. logic would be if you were to add a twin single pole breaker in a full breaker slot you would keep that same number in the case#4 and mark #4,a and #4,b in this way you are assured the correct circuit and not throwing the manufacturer's numbering system off . This is a safety concern . Is there anything in the NEC that refers to what I'm referring to?

 

[infinity]

The NEC doesn't really care how you number them it just needs to be a method that is understandable. Here's the actual code section:

408.4 Field Identification Required.
(A) Circuit Directory or Circuit Identification. Every circuit and circuit modification shall be legibly identified as to its clear, evident, and specific purpose or use. The identification shall include an approved degree of detail that allows each circuit to be distinguished from all others. Spare positions that contain unused overcurrent devices or switches shall be described accordingly. The identification shall be included in a circuit directory that is located on the face or inside of the panel door in the case of a panelboard and at each switch or circuit breaker in a switchboard or switchgear. No circuit shall be described in a manner that depends on transient conditions of occupancy.

 

[don_resqcapt19]

You can number them any way you want to, but I would never change an existing circuit number as there may be wire tags related to the original number. The twin would use "A" and "B" or "T" and "B" or something like that.

 

[zbang]

Always A/B L/R T/B etc, whatever makes sense for the panel (I use A/B).

Not an issue for the OP, but someone else may read this-
While we're at it, use the space numbers in the panel, do not use ordinal numbers on the breakers (if a space is skipped, skip that number).

 

[Gtsco12]

The NEC doesn't really care how you number them it just needs to be a method that is understandable. Here's the actual code section:

I do understand. My contention was as we look at a panel from left to right #1 starts on left and #2 follows to the right side of the Bus so why would we change the numbering order of the of the right side of panel is order to accommodate slot 4 which becomes #4#6 in 4 slot in this case example. As you are aware this throws the numbering sequence off to the Electrician as he or she would be counting left to right 12345678 in that order. The entire right side of panel numbering is thrown off sequence. this is why I agree with the post keep the twin breaker like it was full size but label each pole a distinguished letter like a,b or something other then throwing the right side off. If anything else I would like this to be added to the NEC as a change.

 

[kwired]

Some but not all "load centers" have numbering stamped into the cover. Others have no factory identification of this kind whatsoever.

Get into something like I-Line panels or similar where the physical size of what breaker can be installed can vary and it is not all that great of an idea to use same kind of pre-identification like load centers often have.

I don't really use such numbering on new installs anymore, I almost always attach a label from a label maker with information on it about what it serves immediately adjacent to each breaker and don't use the director often supplied on the door. For one thing can print smaller if needed and not deal with possible unreadable handwriting.

 

[infinity]

I do understand. My contention was as we look at a panel from left to right #1 starts on left and #2 follows to the right side of the Bus so why would we change the numbering order of the of the right side of panel is order to accommodate slot 4 which becomes #4#6 in 4 slot in this case example. As you are aware this throws the numbering sequence off to the Electrician as he or she would be counting left to right 12345678 in that order. The entire right side of panel numbering is thrown off sequence. this is why I agree with the post keep the twin breaker like it was full size but label each pole a distinguished letter like a,b or something other then throwing the right side off. If anything else I would like this to be added to the NEC as a change.

You're free to number them anyway that you like. I agree that when the panel uses twin style breakers that A/B for the single slot is simple and easy to understand but it doesn't have to be done that way. It's just one option.

 

[Dennis Alwon]

I always used the a and b

so 14 would be 14 a and 14 b

 

[jap]

I leave a circuited wiring diagram inside the panel cover.
That way you know exactly what all the circuit feeds.

JAP>

 

[tom baker]

I do understand. My contention was as we look at a panel from left to right #1 starts on left and #2 follows to the right side of the Bus so why would we change the numbering order of the of the right side of panel is order to accommodate slot 4 which becomes #4#6 in 4 slot in this case example. As you are aware this throws the numbering sequence off to the Electrician as he or she would be counting left to right 12345678 in that order. The entire right side of panel numbering is thrown off sequence. this is why I agree with the post keep the twin breaker like it was full size but label each pole a distinguished letter like a,b or something other then throwing the right side off. If anything else I would like this to be added to the NEC as a change.

There is a topic here for changes to the NEC. PI’s will be accepted in a few months for the 2026 NEC. Post your PI there and we can review

 

[don_resqcapt19]

I do understand. My contention was as we look at a panel from left to right #1 starts on left and #2 follows to the right side of the Bus so why would we change the numbering order of the of the right side of panel is order to accommodate slot 4 which becomes #4#6 in 4 slot in this case example. As you are aware this throws the numbering sequence off to the Electrician as he or she would be counting left to right 12345678 in that order. The entire right side of panel numbering is thrown off sequence. this is why I agree with the post keep the twin breaker like it was full size but label each pole a distinguished letter like a,b or something other then throwing the right side off. If anything else I would like this to be added to the NEC as a change.

The numbering of the panel is a design issue and not an NEC issue. Square D used to provide numbering labels for the odds on the left and evens on the right along with a set of 1-20 for the left and 21-40 for the right. It is also common to see panels with all three phase breakers numbered with 1 on the first three pole breaker on the left and 3 on the second 3 pole breaker on the left and so on.

The NFPA system will be open for the submissions of Pubic Inputs to make a change for the 2026 code this fall right after the 2023 code is published. The PIs are easy to submit online. If you think this is a needed code change, I am looking forward to reading your PI when the first draft report for the 2026 code is published.

 

[Gtsco12]

Does anyone know how to go about submitting a personnel inquiry to the change the current code on submitting this twin breaker numbering and identifying?

 

[infinity]

Does anyone know how to go about submitting a personnel inquiry to the change the current code on submitting this twin breaker numbering and identifying?

Someone will post the link. Can you post your public input for this code change so that we can see it?

 

[don_resqcapt19]

Does anyone know how to go about submitting a personnel inquiry to the change the current code on submitting this twin breaker numbering and identifying?

It it pretty much all online now at NFPA.org/70, but the system will not be open to submit public inputs to make a change for the 2026 code until this fall after the 2023 code is published.

The submission of PIs for the 2026 code will end in the fall of 2023, so there will be about a year to submit a change. When they are taking changes, the page will have a click box that says "submit public input". There will also be instructions on how to submit the PI.

The first thing you will have to do is select a location in the code for your proposed rule as there is no existing rule. Maybe a new first level subdivision for 408.4. You have to provide the text for the new rule and you have to provide a technical substantiation as to why the new rule needs to be in the code and telling the code making panel what problem your proposed rule will fix.

 

[kwired]

Does anyone know how to go about submitting a personnel inquiry to the change the current code on submitting this twin breaker numbering and identifying?

What is your substantiation that makes this an improvement to safety of life or property from the use of electricity?

 

[Phil Timmons]

I number 120/208/240 panels in Binary, and 277/480 panels in Hexadecimal.

I figure that is very helpful, and just the kind of guy I am.

 

[winnie]

The manufacturer label should define breaker numbering, including tandem breakers if permitted.

The 'skinny' breakers are only permitted in particular locations in a panel, and may not be permitted at all in some panels.

The panel label will generally have a schematic that shows this. The associated panel schedule will have different numbering for the areas that accept tandem breakers and those that do not.

Jon

 

[kwired]

I number 120/208/240 panels in Binary, and 277/480 panels in Hexadecimal.

I figure that is very helpful, and just the kind of guy I am.

Whatever works for you.

Use Greek alphabet for references if you want, or even Chinese characters. It is a design decision.

 

[kwired]

The manufacturer label should define breaker numbering, including tandem breakers if permitted.

The 'skinny' breakers are only permitted in particular locations in a panel, and may not be permitted at all in some panels.

The panel label will generally have a schematic that shows this. The associated panel schedule will have different numbering for the areas that accept tandem breakers and those that do not.

Jon

Most them anymore have a pretty generic label that is used for more than one particular panel.

Some (certain load centers) don't even have a "panel label" but rather have label alongside the breakers and you write information adjacent to the breaker it applies to. I happen to do this with my own label maker most the time even if the panel already has numbering system and/or some sort of directory on the door.

N3R panels often those factory labels with handwriting on them don't last long. Particularly on the farm applications I work on. I like my label maker labels much better for such applications, they usually last a long time.

 

[don_resqcapt19]

The manufacturer label should define breaker numbering, including tandem breakers if permitted.

The 'skinny' breakers are only permitted in particular locations in a panel, and may not be permitted at all in some panels.

The panel label will generally have a schematic that shows this. The associated panel schedule will have different numbering for the areas that accept tandem breakers and those that do not.

Jon

Mine just has dotted lines for the spaces where you are permitted to install tandems. There is an "R" in front of the space for the description for the area below the dotted line. The original tandems for this panel had the handles in a horizontal layout and the "R" is for the circuit connected to the right hand handle on the breaker.