What is the box behind a light fixture called?

Author: Dr. Guy Hintz  |  Last update: Friday, February 27, 2026

These are electrical boxes, often referred to as junction boxes. They are responsible for enclosing the wire connections in your home.

What happens if you don't use a junction box?

Your home will remain safe even without a junction box if all electrical connections are secured. That means the wires are not loose and hard to reach, especially by kids and pets. No need for junction boxes for equipment that comes with its own enclosures.

What is the purpose of an electrical junction box?

A junction box is an electrical enclosure that houses one or more wiring connections. The box protects the connections, which usually contain vulnerable points such as wire splices, from environmental conditions and accidental contact.

What are those electrical boxes called?

Electrical boxes, also known as junction boxes, enclose wire connections. They help protect against short circuits, which can cause fires. This guide describes the different types of electrical boxes, their materials and their applications. They come in many shapes and sizes to fit wherever you need them.

Does an electrical box have to be flush with drywall?

The front edge of the box must be flush with the finished wall surface, usually 1/2-inch-thick drywall. Some boxes have depth gauges. You can use a scrap of drywall to position the box.

Why Do Electrical Boxes Need To Be Installed Behind Light Fixtures?

What is the electrical box after drywall?

An old work (retrofit) electrical box is a type of electrical box for outlets, light switches, and other devices that is installed after drywall has already been put in place. This allows you to retrofit an existing wall or ceiling without going through the hassle of removing drywall and plaster.

Should back box be flush with wall?

Agree. Flush with plasterboard, otherwise you'll have to cut tiles accurately up to the sticking out box edges.

What is the box behind a light switch called?

Whether you are working on a remodeling job or a brand new home build, you may have seen these precarious square boxes throughout your home's walls and ceiling. These are electrical boxes, often referred to as junction boxes. They are responsible for enclosing the wire connections in your home.

Do light fixtures need a junction box?

For example, if you have a light fixture that doesn't need a box for mounting, but the wiring connections are not protected by some kind of cover, then you cannot use the fixture without a junction box. If a fixture meets all of the criteria of a box but lacks a cable clamp, don't use it without a box.

What is an outlet box for a light fixture?

Standard rectangular boxes, or single gang boxes, are used for single light fixture switches and outlet receptacles. They are generally about 2 inches wide by 4 inches tall, and their depths range from 1-1/2 inches to 3-1/2 inches. Standard rectangular boxes can be metallic or non-metallic.

What junction box for lighting circuit?

The amp rating is critical; for example, a 20-amp junction box is ideal for lighting circuits, while 30-amp and 40-amp options are more suited for high-power appliances like cookers or showers.

What type of boxes are used for wall mounted lighting fixtures?

Round Boxes for Light Fixtures

Round electrical boxes are used for wall-mounted light fixtures, such as sconces. They are designed to support the fixture's weight and provide a secure mounting point.

What does an electrical junction box look like?

A small metal, plastic or fiberglass junction box may form part of an electrical conduit or thermoplastic-sheathed cable (TPS) wiring system in a building. If designed for surface mounting, it is used mostly in ceilings, concrete or concealed behind an access panel—particularly in domestic or commercial buildings.

Is it against code to put a junction box in the wall?

Additionally all junction boxes in attic should be under a face plate. Concealing a junction box entirely within the wall is prohibited.

Can I leave a junction box in the ceiling?

You can't conceal junction boxes in ceilings, walls or non-accessible attics and under-floor areas.

Can I install a junction box myself?

If you're not comfortable working with wires and electricity, you should hire an electrician to do this job for you. But with the proper safety precautions, you may be able to DIY this job at home.

How do you install an electrical light fixture junction box?

Install a Junction Box
  1. Mount the Box. Separate the circuit wires at the existing splice and loosen the cables as needed to make room for the new junction box. ...
  2. Attach Clamps to the Box. Install a cable clamp for each cable, as needed. ...
  3. Secure the Cables. ...
  4. Join the Wires. ...
  5. Fit the Wires in the Box.

Do lighting junction boxes need to be accessible?

Junction boxes with screw terminals must be accessible for inspection... Junction boxes are commonly used during alterations and additions to an installation. With certain exceptions regulation 526.3 requires that every connection shall be accessible for inspection, testing and maintenance.

Should a junction box be plastic or metal?

In use for far longer than PVC versions, metal electrical boxes are super-strong, fireproof, and incapable of melting. They offer the greatest level of security for electrical wiring applications. It's also virtually impossible to crush or bend a metal junction box!

Do you need a box for a light switch?

As for compliance, building codes require electrical boxes for every electrical device in a house. Every light switch, ceiling fan, outlet, etc. needs a box. While building code does vary by location, you'll find that requirements for electrical boxes are similar across the country.

What are the three types of junction boxes?

Junction boxes come in various types, including: Metal or Plastic boxes. Wall-Mounted Boxes. Ceiling-Mounted Boxes.

How to find hidden junction box in ceiling?

You may be able to locate a metal junction box using a magnetic stud finder. Junction boxes in the ceiling often have extra blocking around them to hold them in place.

Do junction boxes have to be screwed down?

As standard junction boxes have no cable clamps this means the box must be screwed down and the cables fixed to prevent strain on the connections. Care must be taken with the connectors particularly with stranded cables to ensure all the strands are clamped in the connector.

Should light boxes be flush with drywall?

When you install an electrical box, make sure it is flush with the surface of this drywall strip; this will ensure the boxes are at the proper depth when the walls are finished.

How do you secure a back box to the wall?

Mark the desired location on the wall or surface and cut an opening using appropriate tools. Insert the back box into the opening and secure it in place using mounting lugs or screws.

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