11 Types of Electrical Boxes and How to Choose One

Choosing the right electrical box is crucial for any electrical project. With many types of electrical boxes available, it can get confusing to select the most suitable one. This comprehensive guide will walk you through 11 common types of electrical boxes and factors to consider when selecting one.

What is an Electrical Box?

An electrical box, also known as a junction box, is an enclosure that allows connecting and protecting electrical wires and components. It houses wire connections and mounting points for devices like switches, receptacles, and fixtures. Electrical boxes protect these connections and provide a way to access them for maintenance and repairs.

Electrical boxes come in different shapes, sizes, and materials to suit various applications. The National Electrical Code (NEC) regulates the installation of electrical boxes, including their allowed locations, maximum fill capacities, and minimum size requirements. Using the right box as per code ensures electrical safety.

Choosing the right electrical box starts with understanding the available options and their best use cases. Here are 11 common types of electrical boxes:

1. Standard Rectangular Box

The standard rectangular box, also called a handy box, is the most common type of electrical box. It features four sides and 90-degree angles. These versatile boxes work for a wide variety of electrical components, including:

  • Switches – Single-gang and double-gang switch boxes
  • Receptacles – Duplex receptacle outlets
  • Light fixtures – Basic lighting connections

Rectangular boxes come in a range of standard sizes, with the most common being:

  • Single-gang – Designed for one switch or outlet
  • Double-gang – Houses two switches or outlets side-by-side
  • Triple-gang – Accommodates three devices next to each other

They are available in different depths to manage simple and complex wiring. These non-metallic or metallic boxes suit most indoor installations.

2. Round Ceiling Box

As the name suggests, round ceiling boxes mount flush to the ceiling. They allow installing lighting fixtures and ceiling fans. Round boxes feature a domed circular design with one or more knockouts. These boxes come with attachment points to mount the ceiling luminaire or fan.

Their round shape saves ceiling space and provides a neater appearance. Round ceiling boxes work well for rooms with no attic space above. They come in a range of sizes based on application:

  • 4 inch – For lightweight fixtures like a pendant light
  • Pancake box – For heavier flush-mount lights and fans
  • Dome fixture box – For large chandeliers and bigger fans

Using an appropriate round ceiling box provides Sturdy support for the lighting unit. This prevents vibrations and damage to connections.

3. Octagon Box

Octagon electrical boxes, as the name suggests, come in an eight-sided, octagonal shape. The flat panel design allows mounting over the electrical box to provide decoration. It can accommodate a light fixture, receptacle outlets, or switches.

Octagon boxes feature mounting holes and wire clamps. This makes them ideal for installing:

  • Ceiling lights and fans in the center of a room
  • Decorative receptacles and switches
  • Fixtures where looks and appearance matter

They come in 3.5 inch, 4 inch, and larger sizes with different depths. Octagon boxes give an aesthetic appeal, along with reliably housing wires and connections.

4. Square Box

Square electrical boxes provide another common option for electrical wiring. As the name suggests, these feature four-sided square designs.

Square boxes are suitable for:

  • Wall sconces
  • Light fixtures
  • Switches and receptacles

They can accommodate multiple wires, switches, and outlets, making them ideal for three-way switching. Square boxes provide the wiring capacity of rectangular ones in a more compact size.

5. Concrete Box

Concrete boxes, or masonry boxes, are designed for installation in concrete walls and floors. They feature tapered sides to wedge into the poured concrete.

These sturdy boxes suit industrial environments. They prevent water ingress and withstand dirt, debris, and physical abuse. Concrete boxes come with threaded hubs for connecting conduit.

Applications of concrete boxes include:

  • Wet locations – Bathrooms, basements, outdoors
  • Workshops and garages
  • Warehouses and factories

They provide a heavy-duty wiring housing for switches, outlets, and junctions when set in concrete. Concrete floor boxes also allow power provision in commercial spaces.

6. Bracket Box

Bracket or nail-on boxes provide an easy installation option on wooden stud walls. They feature keyhole slots on the back and come with mounting nails or screws.

Bracket boxes allow quick mounting on:

  • Wooden studs in drywall construction
  • Wood paneling
  • Exposed joists and beams

Their small and adaptable design works well for installing lighting fixtures and wiring connections. It eliminates the need to cut into studs to embed boxes.

7. Gutter Box

Also called a wireway or lay-in box, a gutter box is designed for high-capacity wiring. It features a extended narrow design with removable covers.

Gutter boxes accommodate multiple wires in applications like:

  • Subpanels and service panels
  • Raceways and wire runs
  • Commercial lighting circuits

The wiring lays into the box through the open side. The cover locks into place once all connections are made, protecting the wires inside.

8. Junction Box

Junction boxes provide protected enclosures for joining multiple wires and cables. They house wire connectors like wire nuts to join:

  • Feed wires to fixtures
  • Multiple branch circuit wires
  • Incoming and outgoing power lines

Junction boxes feature removable covers to allow access to the wiring within. They are not intended for mounting devices and come with few or no knockouts. Junction boxes simplify complex wiring in commercial, industrial, and residential settings.

9. Floor Box

Floor boxes allow making electrical connections through openings in floors. They are cast into the flooring and covered with a flush plate when not in use.

Typical applications include:

  • Power and data for conference tables
  • Connections for displays and workstations
  • Temporary outlets for events

The flat covers get removed to access the receptacles and connectors when required. Floor boxes eliminate power cords running across hallways and aisles.

10. Hubbell Box

Hubbell boxes provide a unique “built-in” look for receptacles and switches. It features a classy finish plate that mounts directly over the electrical box.

Some benefits include:

  • Sleek, high-end appearance
  • Fits with any decor
  • Quick and easy installation

Hubbell boxes come in various configurations for switches, outlets, and combinations. They suit wall sconces, receptacle outlets, and decorative wall lighting.

11. Explosion Proof Box

As the name indicates, explosion proof (XP) boxes provide safe connections in hazardous locations. They prevent combustion from entering or escaping the box.

Typical hazardous locations include:

  • Refineries, oil rigs, and fuel storage areas
  • Chemical and paint facilities
  • Metal processing plants

Explosion proof boxes ensure safe, continuous operation of electrical systems when flammable gases or vapors are present nearby.

Now that we’ve looked at common electrical box types, how do you pick the right one? Consider the following factors:

How to Choose the Right Electrical Box?


Consider what the electrical box will house – a light switch, outlet receptacle, or junction wires. This determines suitable box types and required capacity.


Wall, ceiling, floor, and outdoor boxes have different designs to suit their placement. Matching location avoids code violations.

Box Size

Size the electrical box to hold all wires, devices, and connectors per NEC rules. Undersized boxes increase fire risks.

Single-gang vs. Multi-gang

Single-gang boxes fit one device. Multi-gang ones can hold multiple devices side-by-side.

Available Space

Check space availability to pick an appropriately sized flush or surface-mount electrical box.


Metal, non-metallic, weatherproof, and concrete boxes suit different needs like durability and corrosion resistance.

Ease of Installation

Consider whether to simplify installation with nail-on, lay-in boxes, or cast-in concrete boxes.

Future Expansion

For additions, larger boxes like oversized octagons allow fitting more wires later.

Local Codes

Your local electrical code determines allowed box types for specific uses.

With all these factors considered, you can select the ideal electrical box for your light fixtures, switches, outlets, and permanent junction connections.

Frequently Asked Questions

What is the most common type of electrical box?

The standard rectangular or square box is the most frequently used electrical box type. It offers a versatile way to house outlets, switches, and basic light fixture connections.

What box is required for a ceiling fan?

Ceiling fans require sturdy support and vibrations resistance. Use a heavy-duty 4 inch round ceiling fan box secured to framing for optimal safety.

Where should you install a junction box?

Junction boxes connect different wiring segments. Typical locations include above ceiling lines, inside walls, and concealed areas like attics and basements.

What are concrete boxes used for?

Concrete boxes provide strong and durable electrical housings embedded into concrete floors, walls, and foundations. They suit wet areas and high-abuse conditions.

How deep should electrical boxes be?

Electrical box depth depends on the number of wires, devices, and connections. Shallower boxes work for basic wiring. Deeper boxes allow fitting more wires and complex circuits.

Can you install two outlets in one box?

Yes, installing multiple outlets in one box is permissible. Use an adequately sized double or triple-gang box to safely fit two or more receptacle outlets.

How much weight can a ceiling electrical box hold?

Non-fan ceiling boxes may hold up to 50 lbs. Fan-rated boxes support 70 lbs or more. Heavier light fixtures require more strongly braced boxes.

Should conduit be grounded to an electrical box?

Metallic conduit must be grounded at the panel, but not necessarily at the electrical box. Use grounding bushings to ground larger boxes.

Do enclosed splices need a junction box?

Yes, the NEC requires enclosing all splices in an approved junction box. Never leave exposed or unprotected wire splices.

Can you bury an electrical box in the ground?

Outdoor electrical boxes meant for direct burial can get buried underground. Indoor boxes will corrode and fail if buried. Use weatherproof boxes.


Choosing and installing the proper electrical box ensures safety while meeting code requirements. Consider where the box will go, what it will contain, and likely expansions. Matching the right box size and type for the application avoids expensive replacements later on.

Pay attention to material durability and allowed locations noted in the local electrical code. With many box options like rectangles, octagons, ceiling round, and concretes, pick the optimal one suited for your electrical connections.

Use junction boxes to safely enclose complex wire splices. The right electrical box organizes wiring and provides ample space for making reliable connections. Following manufacturer ratings also prevents electrical hazards.

While the common rectangular metal box meets most needs, specialized boxes cater for ceilings, floors, wet areas, and hazardous locations. Understanding the purpose and placement allows picking a code-approved option. This ensures your electrical projects start on a safe and robust foundation.