Are You Allowed To Splice Or Pigtail In A Breaker Panel?

Have you ever opened a breaker panel and thought it looked about as neat as a bowl of colorful spaghetti? Mixed-up strands in a bowl of spaghetti are just what you want, but when it comes to a breaker panel, you want neat and safe. This will mean occasionally splicing and pigtailing wires in a breaker panel for repairs and using wire nuts to safely run wires.

Wire splicing and pigtailing are allowed in a breaker panel and expressly permitted by NEC 312.8 (A). In the case of correcting a double-tap, when extending wires and when moving circuits, splicing and pigtailing are necessary. Provided these are done correctly, and with wire nuts, it is allowed.

Even though it can sometimes look a little untidy, a breaker panel with many wires, wire-nuts, splices, and pigtails can be safe and compliant. If you are looking in your own breaker box and you want to make sense of the ‘spaghetti soup’ in there or if you are looking to see if your breaker box is compliant, stick with this article to give you all the information you need. With a few pieces of NEC Code, some information, and a fresh look in the breaker box, it will start to make more sense.

National Electric Code 312.8 Permits Splices And Pigtails

Various shrink tube connectors and some wire
Various shrink tube connectors and some wire

Before getting into the details of what splicing and pigtailing are, how to safely splice and pigtail in a breaker box, and other handy information for what’s going on in there, it is good to know the actual National Electric Code (NEC) that permits splices and pigtails. 

This is an extract of NEC 312.8. Electrical Certification. Consultants Thompson Learning lists the extract on their website:

“312.8 Switch and Overcurrent Devices Enclosures. The wiring space within enclosures for switches and overcurrent devices shall be permitted for other wiring and equipment subject to limitations for specific equipment as provided in (A) and (B).”

“(A) 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 complying with 110.21(B) is applied to the enclosure that identifies the closest disconnecting means for any feed-through conductors.”

NEC 312.8

Bear in mind that all three conditions have to be met to be compliant with the NEC, but none of the conditions are onerous, and with these three key pieces of knowledge, you will be able to quickly see if your breaker box is compliant and where some problems may be. If you do see any issues, there are some easy fixes.

What Is Splicing And Pigtailing In A Breaker Panel?

An electrician working on an outlet
An electrician working on an outlet

Despite the sound of it, a pigtail has nothing to do with farming, and a splice sounds complex but can be as simple as connecting two wires together. Knowing what pigtailing and splicing are will mean being able to identify them in a breaker box, check if they are compliant, and check that they are safe. 

Pigtailing is a technique used in electrical wiring to lengthen wires that are too short in a breaker box to be able to reach where it needs to go. It can also be used to combine multiple wires together, leaving one conductor wire to attach in the right place in the panel. 

Essentially a length of wire no shorter than six inches is attached to single or multiple wires so that only one wire is placed in the breaker connection and the joining of wires is handled safely. 

Only one wire can be connected at the breaker connection, so if multiple wires need to be placed in a breaker connection, this is the best and safest way to do it. Connect the wires together to the pigtail wire with a wire nut and run the pigtail wire to the breaker connection and screw it down.

In electrical wiring, splicing is the process of connecting the endpoints of two or more cable conductors to join the wires together. Most often, this is used to connect and lengthen a wire that has become severed for some reason or a wire that needs to be extended. 

Various electrical insulation tapes and shrink tube connectors
Various electrical insulation tapes and shrink tube connectors

You may find a spliced wire in a breaker panel because a wire was cut and needs to be extended, or a breaker connection has moved, and the wire feeding into it needs to be extended.

Reasons To Splice In A Breaker Panel

Wire splices are allowed in a breaker panel, so you will often find them in one. In many cases, they are even necessary to complete repairs to the breaker panel. 

If breaker connections are moved inside the box, or the whole breaker panel is moved or re-wired, it may be that some wires entering the box no longer reach the breaker connection they are supposed to. Here a wire splice will solve the problem. 

When splicing wires in a breaker panel, keep these two things in mind:

1) A wire nut or other approved connector must be used so that the connection is safe.

2) All wires must be the correct size and compatible with the amperage rating of the breaker they are connected to.

Reasons To Pigtail In A Breaker Panel

Occasionally you will see a case where two (or more!) wires have been placed in one breaker connection. This is called a double tap and is considered unsafe.

The breaker connection is not designed to accommodate more than one wire, and the possibility of a loose connection is high. A pigtail is a good method to correct a double-tap at a breaker connection.

Pigtailing within a breaker panel is permitted and is quite safe, provided the pigtails are made up properly and do not occupy more than the allowed amount of space as laid out in NEC 312.8(A).

Are There Alternatives To Pigtailing And Splicing?

A breaker panel with various connected wires
A breaker panel with various connected wires

Unfortunately, unless you are willing to re-wire whole sections of a circuit, there often isn’t an alternative solution. However, as long as you don’t exceed 40% of the cross-sectional area of the breaker box, the total area of all splices and conductors doesn’t exceed 75% of the breaker panel, and you have the correct labels on the enclosure, then using pigtails and splices in a breaker panel is safe and compliant.

How Do You Know If The Breaker Panel Is Compliant?

Short of measuring each connection, splice, pigtail, and tap, how will you know if you have used more percentage of space than you should in the breaker panel? Mike Holt of Mike Holt Enterprises has a great 2.46 minute YouTube video explaining how to do this:

Essentially, he states that the box itself will tell you. If you must move wires and connections around in the box or if the door has to be pushed shut to hold all the wires, then you have used too much space. In general, it is always better to keep the number of splices and pigtails to a minimum.

How To Splice A Wire Safely

Various wires some connected with wire nuts inside a wall outlet
Various wires some connected with wire nuts inside a wall outlet

If you are reading through this post because you want to splice a wire in a breaker panel, one of the easiest ways to do this is with the help of a twist-on wire cap, often called a ‘wire nut.’ 

In some states and jurisdictions, only an electrical professional, usually approved by a council, is allowed to make changes and electrical repairs in a home. If this is the case in your area, then call the professional.

These basic steps will guide you through how a wire splice is typically done:

  • Ensure the wires you are about to splice can be spliced together and will not cause a short circuit or other problem by being joined
  • Strip about ¼ inch of the protective casing off each wire 
  • Press the endpoints of the wires together so that they touch each other
  • Place the twist-on wire cap over the exposed wires and twist in a clockwise direction until the wire nut is tight
  • Gently pull the wires. If they stay in place, they are secure. If they fall out, twist the wire nut more
  • Connect both the wire caps and the wires with electrical tape
  • Cut the tape when the splice is complete

Conclusion

Wire splicing and pigtailing are allowed in a breaker panel, and these connections are expressly permitted by NEC 312.8 (A). It may look a little untidy at times, but a breaker panel with many wires, wire nuts, splices, and pigtails can be a completely safe and compliant breaker box. 

That is, of course, if the correct conditions are met in terms of NEC 312.8(A): Don’t exceed 40% of the cross-sectional area of the breaker box with splices and wire nuts, make sure the total area of all splices and conductors doesn’t exceed 75% of the breaker panel and make sure to have the correct labels on the enclosure.

With this information, you can look in your own breaker box, see if it is compliant and correct it if it is not or call an electrical professional.