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Can I Wire Multiple Circuits In One Junction Box: Answered

You are required to wire lines coming from different circuits. But unsure if it will be alright to put them in a single junction box. Well, we understand your confusion and have a perfect segment dedicated to your problem.

Can you safely wire multiple circuits in one junction box?

Of course, you can! It is safe to wire lines coming from different circuits in one junction box. In that case, you need to pick a box that can accommodate all the wires. Just keep the hots and the neutrals of each circuit separate and wire the grounds together using pigtails. You can also put switches in there if you want to.

Want to learn more about it? We’ve got a step-by-step process that will make it easier for you. Plus we’ll cover different types of junction boxes that you can use in such cases.

So without any further delay, let’s dive in!

Is It Safe To Wire Two Or More Circuits In A Junction Box?

When it comes to electric works, being sure before taking any step is a good thing. Also, wear your safety kits beforehand as electricity is lethal.

Yes, there is nothing wrong or unsafe in wiring more than one circuit in a single junction box. It can be done without any hassle if you know about the basics of it.

You must keep connections coming from different circuits separate from each other. You may divide the junction box into multiple parts to make it easy for you. 

As a box can accommodate a limited number of devices and wires, we recommend using one with larger dimensions. A big junction box gives you room to work with and makes it easier to check while conducting a home electrical inspection.

You can choose the right junction box as per your requirement from these recommended products below. 

Product 1
Product 2 

These are some of the excellent products that are currently available. You can use these without having to worry at all.

Wire Multiple Circuits In One Junction Box: A Step By Step Guide

If you’ve previous experience of working with junction boxes, it won’t seem much complicated to you. But if you haven’t, make sure you are following every step carefully. One tiny careless mistake can cost you big time in such cases.

Precautions and Tools

Turning off the main service line is the first thing that you should do before working on anything related to electricity. Also, put on your safety gear and keep the tools organized. The tools you will be needing are- utility knife/cable ripper, pliers, wire nuts, switches, and screwdriver.

Step-1: Separate and Label

The first thing you’ll need to do is to separate the wires coming from different circuits. You must keep the lines from different circuits separate from each other. You don’t want the connections to get altered.

To keep it organized, we recommend using labels on the wires. It helps you to differentiate the wires coming from different circuits and makes it easier to work with. You can use a marker on the sheathing to write as well.

The label should contain hints of where the wire is coming from. It makes matching the wires with the service line very convenient.

Step-2: Identify the Hot, Neutral, and Ground Wires

The next step is to identify which wire is what. You need to pick out the hots, neutrals, and ground wires to be able to move forward. Again, go circuit by circuit and keep the wires separated.

Usually, you can identify them by color. The black or red one is the hot wire through which the electricity flows. The white or silver one is the neutral wire. The leftover wire is the ground wire.

Ground wire comes in two types. Bare wire (copper) or with green sheathing. The ground wire is referred to as grounding wire and the neutral wire is referred to as grounded wire.

Step-3: Tie the Ground Wires Together

After identifying the wires, the main process of wiring them together starts. There is a simple thumb rule for wiring the circuits. Wire the hot and neutral wires separate, and ground wires together.

So basically, you will need to get the ground wires of all the circuits you wish to put in the box together. Depending on the gauge size of your wires, put pigtails at the end of grouped wires.

For 14 gauge wires, split all the ground wires into groups of 3/4 and pigtail them together. Use wire nuts to seal the end of the wires and give them gentle twists to lock in place. 

Step-4: Wire the Hots and Neutral of Each Circuit Separately

After wiring the grounds together, now comes the part of working with the hots and the neutrals. Again, keep them sorted and separate. If you mistakenly cross pair wires from different circuits, the circuit breaker will trip instantly.

Work with the circuits, one at a time. Take the neutrals of a circuit, strip 0.5-1 inch and wire them together using wire nuts. You can add a pigtail to it if you plan to use a smart switch. After that, roll them into the junction box and start working on the hot wires.

Identify the wires from where the power is coming into the box and going out of the box. Combine the wires and add a pigtail to it which will go to the switches afterward. Follow the same procedure for the other circuits as well.

Step-5: Install the Switches

Now comes the final part, attaching the pigtails from the wires to a switch. A switch can be of different types; two-way, three-way, wifi switch, smart switch, motion sensor switch, etc. We are huge fans of wifi switches but you can use whichever you want.

Keep the pigtails that attach to the switches close to 4-6 inches long. This makes opening the box and maintenance very convenient. Take the switch of your choice and wire the pigtails of the hot wires to the switch. Now, add the ground wires as well.

In terms of using a smart switch or a motion sensor switch, you need to add the pigtail from the neutral wires as well. Finally, fix the switches to the box, and with that, you are done wiring multiple circuits in a single junction box.

Different Types Of Junction Boxes

Depending on the dimensions, junction boxes can be of different types. If you are just buying a junction box, you may choose a junction box that allows you to connect multiple circuits in one. It should have room to fit all the wires.

Now, let’s have a look at some of the variants of junction boxes-

Standard Rectangular Box

This is a common type of junction box that you will find almost everywhere. It is typically referred to as one gang or single gang box. It is usually 2×3 inches in size with a depth of around 1.5 to 3.5 inches.

2 Gang, 3 Gang, and 4 Gang Boxes

These are the larger variants of standard junction boxes. You can just pick a bunch of standard boxes together or take 2 gang, 3 gang, and 4 gang boxes; whichever you prefer. They function the same, but these boxes are more convenient for larger connections.

Octagon and Round Boxes

Convenient for old-work applications, these different shaped boxes are widely seen in electrical works. These usually have a depth of 1.5 to 3 inches. These are conventionally used for ceiling or wall-mounted fixtures.

4-Inch Square Box

This is the square variant of the standard rectangular box. As the name suggests, it is 4 inches in size with a depth of 1.25 to 2.125 inches. These have plenty of room to cover wire splices and other delicate components.


Question: Can I use two circuits in a dual gang box?

Answer: Yes, it is perfectly fine. Multiple circuits can exist in a dual gang box. If the wiring is done perfectly, there’s no need to worry about it.

Question: Can I wire splice circuit wire without a junction box?

Answer: No, we fear not. It is a must to have a junction box in such situations. Not only that, you need proper access to the junction box.

Question: Is it possible to extend wiring using a junction box?

Answer: Yes. It is an easy and effective way to fix wiring issues around the house. We have a full-fledged available on how you can use junction boxes to extend wiring.


This marks the end of our departure. Hope this has resolved your confusion about having multiple circuits in one junction box. If you need any further assistance, we would strongly recommend you seek help from a professional 

In short, there’s no harm wiring more than one circuit in a junction box as long as you’re doing it right. Follow our instructions and be safe around electricity.

Best of luck in your future endeavors!