Can You Use A Junction Box To Extend Wiring? (Find Out Now!)

Upgraded Home Team
by Upgraded Home Team

There are many reasons for homeowners to want more accessible wiring. To do this, electrical work is needed, which often brings up the question “can you use a junction box to extend the wiring?”

You can use a junction box to extend wiring. First, turn off your power at the main breaker. Next, cut openings and fit the wires through the box. Once the wires are connected, fit the box back in place. Patch up any remaining holes and turn the power back on.

Maybe you want add-ons for more appliances, or maybe you want to extend wires further to put more outlets. Whatever your reasoning, let’s take a look at how you can use a junction box to extend wiring.

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What Exactly Is An Electrical Junction Box?

To understand what you can and cannot do in extending wiring, let’s cover the meaning of an electrical junction box.

An electrical junction box is the primary source of the wiring system. It’s available in metal or plastic. Known as the control box or distribution center, it is the meetup source where power comes from the breaker and is then dispersed. Multiple cables are hooked up and stored inside the electrical junction box.

If there is no box, then there are no switches, outlets, or data hookup areas in any room.

Why Should I Use a Junction Box?

After the wires meet in the junction box, the power is then re-routed to each circuit. If a line isn’t long enough, then one can be added.

The alternative to a junction box is to splice wires together. Splicing wires usually doesn’t meet building safety codes. This is because sometimes, the wires can’t be spliced with a safe enough length, which is another reason to extend wires.

Safely Working with Junction Boxes

The main thing to remember is the electrical junction boxes have to be put in a safe place. The best places to put them are in attics, inside drop ceilings, basements, behind the paneling, or drywall. It should be where there is no foot traffic or in danger of getting bumped.

The new building regulations code Part P should be read and understood before doing any electrical work. If the homeowner did the electrical job, they should inspect the work and have a professional double-check it.

What is the Purpose of a Junction Box?

Electrical junction boxes connect additional sockets to add lighting points, circuits, and extend circuits. Its goal is to get power from one point to another and also for repairing wires. For a damaged wire, cut and splice them together, then use the box to reconnect the wire.

A junction box can join the wires or safely run a spur from an electrical circuit. It is recommended to use a junction box when connecting two or more wires. Anyone involved in electrics and wiring knows their value and uses the boxes often.

The box serves as a protector from any exposed live wires as it bundles up to three to five sets. It also prevents the wires from touching, which can also be dangerous. Installing a junction box ensures the wires aren’t bumped or touched by human hands.

How To Wire Junction Boxes

The following steps explain how to wire a junction box. To add extensions, follow the same procedures. If the box is to go behind the wall, then cut the appropriate amount of space to install everything. The process is the same no matter the type of junction box or rating you install.

Step 1: Turn Off the Power

Before touching any wire, turn off all the power at the main breaker. Check the wires with a tester to be sure there are no live wires.

Step 2: Create a Spur

Spurs are for adding additional lights, sockets, or outlets in different areas of the home. Match all of the color wires together by putting them in the terminals and connecting them. The straight ends will come from the main cables, while the side ones will spur the additions.

In order to reveal the core of the cable, strip them of the minimal amount necessary. The wires are as follows:

  • Hot wires are red or brown.
  • Neutral wires are black or blue.
  • Earth or ground wires are yellow or green.

Step 3: Secure the Base

There will be open holes to screw the base to the wall. Once the wires are in place, the base goes first; then, the cover will screw on top.

Step 4: Put Everything Back Together

If the box is on the wall, you are done and can turn the power back on. If the box is behind the wall, put the pieces of wood you cut out back in place. It will take some wood putty, sanding, and paint or stain to make it look natural.

Junction Box Sizing

Getting the right size junction box is vital to cable management. The boxes usually come in sizes of two and a half inches to three and a half inches in depth. On average, a small box may hold up to three wires, while the deeper box will hold up to five different sized wires.

The existing wiring needs to get tied in somewhere if different components will go in a room. A junction box will allow an easy fix by connecting to the main breaker. If the components are compatible with the circuit breaker, the box prevents excess wires from going back to the source.

Explaining The Different Types Of Junction Boxes

There is a range of different types of junction boxes. The two primary differences that are critical to note when purchasing are the rating and terminals.

Junction boxes also come in different styles indicated by each manufacturer. Though the moldings and the terminal layouts are different, the essentials are all the same.

Amp Ratings Of A Junction Box

Each junction box is rated by amps to protect you, the circuit, and the junction box. It is critical to have the box with the proper amp ratings. For example, a radial circuit needs a 30 amp box, while a lightning circuit needs a 20 amp box.

The current of the circuit must match the amp rating on the box. You may use a higher rating box for a lower-rated circuit, but never the other way. If you do, it may cause a meltdown or a home electrical fire.

Terminals And Wiring For Junction Boxes

Junction boxes come with options for multiple terminals, ranging anywhere from 3 to 6 terminals. For price reasons, it is best to choose the only one that is suitable for your needs. When connecting the wires, each end of the wires will fit on each end of the same terminal to connect.

The Types Of Terminals

After connecting the wire inside the terminal, screw the terminal clockwise as each copper end of the wires will secure. There are three different types of terminals that connect the copper ends of the wires. They are as follows:

  • Single Screw Terminal. Each terminal has a screw in a place where each end of the cable passes through to connect. Standard junction boxes are the ones these terminals are mostly found. A flathead screwdriver turns the screw, and both wires connect securely. Each box has a different size opening for different size cables.
  • Bussbar Screw Terminals. Each cable is inserted into its designated hole and screwed down. It is not like the single screw, as both ends need to be securely screwed tight to hold. Every wire must fit the holes accordingly, or it will not stay in place.
  • Maintenance Free/ Easy Connect Terminals. Like the Busbar, each cable has its hole inside the terminal. Levers secure the wires, or it is a push-fit. Each terminal is limited on how many cores are connected, which is between two and eight.

Square Or Round Junction Boxes?

Round junction boxes are standard with receiving lower current cables, while square boxes are for higher currents. There is neither better nor worse between the two, but keeping the compatibility is critical. The maintenance-free junction boxes are a common household product and are rectangular.

The maintenance-free junction boxes seemed to have replaced most of the round boxes. Consumers and electricians prefer these over round boxes. Wiring maintenance-free boxes saves 75 percent of the wiring time compared to the others.

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You can use a junction box to extend wiring. In fact, it’s the preferred method. The alternative—splicing—has its limitations and is usually unsafe and not up to code. When using a junction box to extend wiring, make sure you take proper safety precautions. Look for the correct box size with the proper amount of amps and terminals. Don’t be afraid to call an electrician if you feel this kind of work is out of your league!

Upgraded Home Team
Upgraded Home Team

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