I'd like to convert my existing 100-A panelboard to a junction box (a new 200-A panelboard is being installed about 15' from the existing panel). My naive question: are there any particular rules to follow for making the specific junctions within the new panel? Do I simply use wire nuts to join each individual circuit together, and put a cover on the front like one would do for a simple junction box (like, say, extending a branch circuit)?

I guess my thought was: converting a panelboard to a junction box must make for a bowl-of-spaghetti-looking panel, no?

Can I use the existing panelboard cover as my junction box cover (with the now blank circuit breaker knockouts filled in)?

I'm located in Seattle, USA.

  • Where are you on this planet? Apr 15, 2017 at 20:25
  • Seattle, USA. Just updated my question (thanks for the catch). Apr 15, 2017 at 20:26
  • Is the service wiring being rerouted to go directly to the new service panelboard without making a stop at the old panelboard location, or is it going to be spliced at the old panelboard location between the existing service cable and the new cable going to the new panelboard? Apr 15, 2017 at 20:43
  • Service entrance is moving as well; the new service will not come through the old panel (the existing service is in an undesirable location for the POCO (and me), and the existing service mast is undersized for current building code). Apr 15, 2017 at 20:52
  • Is the existing panelboard indoors or outdoors? Apr 15, 2017 at 21:06

2 Answers 2


Assuming it's not prohibited by your local codes and the existing panel is not violating any current codes like overfill, working space clearance, there's nothing code-wise that says "No this is prohibited".

However, a better solution if possible, since you have to run new wires anyway, is to install a 12x12 or larger junction box in the attic and crawl space and be done with it.

Now it would be wise to consult you Building and Planning Department first as most of the time the Power Co. will not reinstate power unless the work is permitted. Also, not sure about your local jurisdiction but around here they make us install hard-wired smoke alarms in every bedroom and in every hall near a bedroom if a panel is upgraded.

  • I believe it may be possible to convert the existing cabinet into a junction box if the AHJ is willing to OK such a thing (basically, it relies on the fact that panelboard cabinets and large J-boxes both fall under UL 50...) Apr 16, 2017 at 1:07
  • As to why I am thinking that -- Art. 314 applies to all things that house junctions but no equipment (which'd mean a panelboard cabinet with no panelboard inside wouldn't fall under Art. 312 any longer). Apr 16, 2017 at 1:13
  • @ThreePhaseEel Sounds good. I will need to brush up on Art. 314. Thanks !
    – Kris
    Apr 16, 2017 at 1:24
  • @Kris if there is any overload device in the old panel - the use of the box as a junction box is prohibited by code. Also if the panel is converted to a junction box - no overload devices, from what I understand the cover panel will need to be secured with screws. Now all of that also depends on Local Codes not superseding NFPA .which is what my point was. Being in a residence and doing this may deter some buyers if he should decide to sell, and the tricky part is how an inspector will interpret the codes. Personally I have not seen this done in a residence, but does not mean it is not.
    – Ken
    Apr 17, 2017 at 17:27
  • 1
    @Ken, not true. Panels are allowed to be used as junction boxes as long as the capacity is not exceeded, regardless if it is a used panel or an repurposed panel with no service/feeder conductors.
    – Kris
    Apr 17, 2017 at 18:28

You do not say where you are located so I can not answer to your specific question directly. Except to say I have never seen this done in the USA and with good reason. I do believe it is against code to do it - but I am not a NFPA Electrical Code expert - and particular states might vary.

I am assuming you want to change out the panel with a newer panel and simply run wires from new panel to old panel and wire nut inside (maintaining your existing wiring). BAD IDEA. I would recommend that you NOT do it.

Change the panel out in place - remove your old panel and install the new one. Putting the new one 15 feet form the existing - why? can be all kinds of reasons - but if you do not need to do this - Don't - all of your wiring drops to the existing panel area and will be much easier installing the new panel.

EDIT 4/17/2017 As others have pointed out using the panel is permissible : However it is only permissible under certain conditions (and one not listed here is that the panel be screwed shut or locked shut:

From the NFPA [I think the 2011 code states this in 312.8] but I could be wrong on that.

Sec. 373-8 states you shall not use enclosures for overcurrent devices as junction boxes or raceways—unless you provide adequate space. Conductors inside a panelboard shall not fill the wiring space at any cross section to more than 40%, and splices and taps shall not fill the wiring space at any cross section to more than 75%.

Just to be clear as I do not know who in the future will read this i.e newbie DIY'er : Enclosures for Overcurrent devices ; an Overcurrent device is a FUSE or a Circuit Breaker. Enclosures in the above sentence would mean something such as a service panel that has circuit breakers in it, often referred to as a Breaker Panel, Breaker Enclosure etc..

  • Or if you can't put the new panel where the old one is, can you turn the existing panel into a subpanel and put any new circuits into the new panel? That could avoid a lot of rewiring.
    – Mark
    Apr 15, 2017 at 20:34
  • 2
    It could be that his old panelboard is in a place where Code prohibits overcurrent devices or that doesn't meet the clear working area requirements in 110.26... Apr 15, 2017 at 20:53
  • Good suggestions, but not relevant or applicable to my question: the new panel MUST be located in a new location. Apr 15, 2017 at 20:54
  • So given your situation (where the panel must be relocated) - move the wiring into the new panel - or as Mark said make the other a sub panel of your new panel (if code allows you to do so - it most likely will allow for this - but Seattle is different.) Marks method is a cheaper solution. Being that you are in Seattle and from what I know about that area (as I have installed Industrial Equipment in that area) an Inspector will probably have a field day with a non junction - 'junction box', verify that with your local inspectors first. Also you can search NFPA 70 for guidance.
    – Ken
    Apr 15, 2017 at 21:22

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