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When can a panelboard be used for splicing? NEVER!

15K views 3 replies 4 participants last post by  frenchelectrican 
#1 · (Edited)
This is a commonly asked question on this and other forums. Hopefully this thread will provide some answers. Input from other professional electricians is always welcome.

First let’s look at NEC Article 100, Definitions;

Cabinet. An enclosure that is designed for either surface mounting or flush mounting and is provided with a frame, mat, or trim in which a swinging door or doors are or can be hung.

Cutout Box. An enclosure designed for surface mounting that has swinging doors or covers secured directly to and telescoping with the walls of the box proper.

Enclosure. The case or housing of apparatus, or the fence or walls surrounding an installation to prevent personnel from accidentally contacting energized parts or to protect the equipment from physical damage.

Panelboard. A single panel or group of panel units designed for assembly in the form of a single panel, including buses and automatic overcurrent devices, and equipped with or without switches for the control of light, heat, or power circuits; designed to be placed in a cabinet or cutout box placed in or against a wall, partition, or other support; and accessible only from the front.



A panelboard is designed to be installed inside of a cabinet or cutout box. Therefore, it is physically impossible to splice “inside” a panelboard.

So the question now becomes “can a cabinet or cutout box be used for splicing”. To answer that question we need to look at NEC Article 312, Cabinets, Cutout Boxes, and Meter Socket Enclosures.

312.8 Switch and Overcurrent Device Enclosures with Splices, Taps, and Feed-Through Conductors. The wiring space of enclosures for switches or overcurrent devices shall be permitted for conductors feeding through, spliced, or tapping off to other enclosures, switches, or overcurrent devices where all of the following conditions are met:
(1) The total of all conductors installed at any cross section of the wiring space does not exceed 40 percent of the cross-sectional area of that space.
(2) The total area of all conductors, splices, and taps installed at any cross section of the wiring space does not exceed 75 percent of the cross-sectional area of that space.
(3) A warning label is applied to the enclosure that identifies the closest disconnecting means for any feedthrough conductors.

The answer is “yes, splices can be made inside of a cabinet or cutout box” as long as the three above conditions in NEC 312.8 are met.

The next question asked is if the panelboard is removed from the cabinet or cutout box, can the wiring be spliced in the remaining enclosure and extended to the new panelboard location? The answer is yes as long as all three conditions in NEC312.8 are met including #3, which states that a warning label is applied to the enclosure indentifying the closest disconnecting means.

Is the door required to be screwed shut? No, not an NEC requirement.

Finally, if the cabinet or cutout box is used to extend the existing circuits to the new service location there are a few things that need to be done;

1. Remove the neutral bar and extend the neutral conductors through to the new location.
2. The equipment grounding conductors need to be extended through, but make sure the ground bar is still bonded to the enclosure.
3. The existing equipment grounding bar needs to be grounded back to the new service. The wire size shall be based on the largest overcurrent device protecting the branch circuit spliced in the existing enclosure.
4. Multiwire branch circuits can be used to extend existing circuits, but be aware of AFCI and GFCI concerns and circuit breaker requirements.
5. The grounding electrode system will have to be re-routed to the new service location without splices, or spliced using an approved means.
6. All unused openings will need to be effectively closed with approved means.

As always, all comments are welcome!

(V)
 
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#3 ·
From 1974 to sometime in the 90's not one single municipality in and around Chicago allowed any splices in a panel cabinet. Period. End of discussion.

All that changed in the 90's.

If you have two or more hots coming into a panel that are supposed to be terminated on one breaker lug, you need to splice them first, rather than insert each one separately into a breaker lug. So after about 20 years of never seeing a splice in a panel cabinet, it took me a while to get used to seeing them.

The splice issue continued to be seriously debated over the years, with the desired intent to allow them for more applications. We had one guy in our local who must have slept with the code book. He helped ease my mind about seeing those wirenuts in panel cabinets. :huh:
 
#4 · (Edited)
This is a commonly asked question on this and other forums. Hopefully this thread will provide some answers. Input from other professional electricians is always welcome.

I will try to assit ya with some of the answer related to the NEC side ( just becarefull I can hightlight our French codes )


First let’s look at NEC Article 100, Definitions;

Cabinet. An enclosure that is designed for either surface mounting or flush mounting and is provided with a frame, mat, or trim in which a swinging door or doors are or can be hung.

Cutout Box. An enclosure designed for surface mounting that has swinging doors or covers secured directly to and telescoping with the walls of the box proper.

Enclosure. The case or housing of apparatus, or the fence or walls surrounding an installation to prevent personnel from accidentally contacting energized parts or to protect the equipment from physical damage.

Panelboard. A single panel or group of panel units designed for assembly in the form of a single panel, including buses and automatic overcurrent devices, and equipped with or without switches for the control of light, heat, or power circuits; designed to be placed in a cabinet or cutout box placed in or against a wall, partition, or other support; and accessible only from the front.



A panelboard is designed to be installed inside of a cabinet or cutout box. Therefore, it is physically impossible to splice “inside” a panelboard.

So the question now becomes “can a cabinet or cutout box be used for splicing”. To answer that question we need to look at NEC Article 312, Cabinets, Cutout Boxes, and Meter Socket Enclosures.

312.8 Switch and Overcurrent Device Enclosures with Splices, Taps, and Feed-Through Conductors. The wiring space of enclosures for switches or overcurrent devices shall be permitted for conductors feeding through, spliced, or tapping off to other enclosures, switches, or overcurrent devices where all of the following conditions are met:
(1) The total of all conductors installed at any cross section of the wiring space does not exceed 40 percent of the cross-sectional area of that space.
(2) The total area of all conductors, splices, and taps installed at any cross section of the wiring space does not exceed 75 percent of the cross-sectional area of that space.
(3) A warning label is applied to the enclosure that identifies the closest disconnecting means for any feedthrough conductors.

The answer is “yes, splices can be made inside of a cabinet or cutout box” as long as the three above conditions in NEC 312.8 are met.

The next question asked is if the panelboard is removed from the cabinet or cutout box, can the wiring be spliced in the remaining enclosure and extended to the new panelboard location? The answer is yes as long as all three conditions in NEC312.8 are met including #3, which states that a warning label is applied to the enclosure indentifying the closest disconnecting means.

Is the door required to be screwed shut? No, not an NEC requirement.

I am aware with the NEC may say not a requirement but just be aware some of the local code or inspectors may required to be screwed shut it the same with our French codes but screw it shut or make a new blank cover and give the location where the new OCPD's location is.

Finally, if the cabinet or cutout box is used to extend the existing circuits to the new service location there are a few things that need to be done;

DIY's please read this part carefull this is the only legit way you can get done properly.

1. Remove the neutral bar and extend the neutral conductors through to the new location.

Be aware that the " super netrual " is no longer legit for safety reason.

2. The equipment grounding conductors need to be extended through, but make sure the ground bar is still bonded to the enclosure.
3. The existing equipment grounding bar needs to be grounded back to the new service. The wire size shall be based on the largest overcurrent device protecting the branch circuit spliced in the existing enclosure.

Not all the panels will have existing equiment grounding bussbar so therefore you will end up buy one and install it.

And using his example above if you have the largest conductor is #6 AWG grounding conductor then you will have to bring out #6 AWG

Also I will remind again #12 is good for 20 amp circuits while #14 is restricted to 15 amps circuit. Any Alum conductors (becarefull some are tinned copper conductor espcally with old rubber coated conductors) which it will required extra methold to properly spliced.
There are couple approved metholds for smaller conductors but for larger conductors like dryer or range useally three or four differnt common methold but the best is polaris connectors.
4. Multiwire branch circuits can be used to extend existing circuits, but be aware of AFCI and GFCI concerns and circuit breaker requirements.

Before ya start transfer all the circuits to the new panel this is very important to prevent issue will arise if not heeded which you will have to mark all the conductors espcally with MWBC's it have to be in correct sequince.

Do the new panels can take two pole AFCI or GFCI's the answer is oui but check with the manufacter listing to see if the two pole AFCI's are aviable ( useally limited numbers ) but GFCI typically not a issue. But be aware of the cost of two pole AFCI's/GFCI's.
5. The grounding electrode system will have to be re-routed to the new service location without splices, or spliced using an approved means.

For moi the genral answer is run a new EGC conductor but if have to use the exsting one for some reason I use irreveseable connectors for that purpose.

6. All unused openings will need to be effectively closed with approved means.

As always, all comments are welcome!

(V)
Hope that help some of it.

Merci,
Marc
 
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