Use plastic boxes when:
- There are non-metallic (NM) cables leading in or out of the box. Metal-sheathed wiring relies on bonding with the metal electric box for grounding and should not be used in plastic boxes.
- You're doing the job yourself. ...
What are the disadvantages of plastic boxes?
What is an octagon box?
Can metal boxes take a pounding?
Do you need a bigger junction box?
Do you need a ground wire for a plastic electrical box?
Is it better to use a metal box or plastic box?
Can you tap a metal box out?
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Is it OK to use a plastic junction box?
A plastic electrical box might be a better choice for your application if: You're using non-metallic sheathed wire (often called Romex wire). Romex wire and plastic junction boxes are frequently used together, but metal enclosures may be acceptable as well (depending on the project).
Can I use plastic box for outlet?
Though PVC can melt when overheated, it does not conduct electricity like metal does. Use plastic boxes when: There are non-metallic (NM) cables leading in or out of the box. Metal-sheathed wiring relies on bonding with the metal electric box for grounding and should not be used in plastic boxes.
Can you use plastic electrical boxes outside?
Plastic junction boxes can often offer a more cost-effective option than steel or aluminum junction boxes. For many applications, even including many outdoor ones, heavy-duty plastic such as polycarbonate offers comparable or even superior performance to metal.
Can you use plastic electrical boxes on metal studs?
However there's nothing that specifically prohibits the combination of metal framing and plastic boxes. NEC* article 314.23(B) addresses how boxes are mounted, and there's nothing in there that would prohibit you from mounting a plastic box to a metal stud.
Can I use plastic back box in wall?
Different Types and Sizes of Plastic Back Box Essentially it works the same way as a metal back box and is recessed into the walls surface allowing the socket or switch face plate to fit flush with the walls surface.
Do plastic electrical boxes need vapor barrier?
The box is made of durable PVC so it is able to withstand extreme environments both cold and hot. You don't need the vapour barrier behind them and the shape of the box will provide the support for the poly attachment.
Do plastic electrical boxes need to be grounded?
Plastic electrical boxes have their pluses and minuses. Because they are plastic, there is no need to attach a ground wire to it. Since it is made of a non-conductive material, switches and outlets cannot short out if they touch the side of the box.
Does a dryer outlet box need to be metal?
The box can be metal or plastic. Some form of cable clamp is always required, it's just that most plastic boxes have an integrated clamp (that finger-trap style door).
What kind of plastic are electrical boxes made of?
Polycarbonate + Acrylonitrile Butadiene Styrene (PC+ABS Blend) Polycarbonate and Acrylonitrile Butadiene Styrene are some of the most commonly used plastics for electronic enclosures.
What is code for electrical junction box?
Article 334.30 states that cables coming out of the junction boxes should be secured within 12 inches of the box in all boxes equipped with cable clamps.
Are plastic electrical boxes fire rated?
plastic boxes, also on single gang box? If you are discussing fire classification, most of Carlon's blue nonmetallic outlet boxes, with the exception of old work boxes, are fire classified for two-hour fire rated walls or less.
Can you screw a plastic electrical box to a stud?
It is mechanically possible to install a standard new-work box in an existing wall by: Cutting hole in drywall adjacent to a stud. Placing plastic box in the hole up against the stud. Screwing through the plastic into the stud.
Can I replace a metal outlet box with a plastic box?
Homeowners can replace their metal electrical box with plastic if non-metallic cables come in and out of the box. However, the downside of plastic electrical boxes is that they distort or crack under stress, and PVC can melt due to overheating.
What kind of boxes do you use for outlets?
Handy boxes (also known as utility boxes) are typically used to install electrical outlets or switches on exposed surfaces. Intended for indoor use, handy boxes are available in one- and two-gang configurations. Some have a mounting bracket for attaching the box to a wall or a ceiling framing member.
Are plastic outlet protectors safe?
Your kids can—and will—easily learn how to remove them. (100% of toddlers!) Loose plastic outlet covers are a choking hazard.
Can you screw in a plastic electrical box?
It is mechanically possible to install a standard new-work box in an existing wall by: Cutting hole in drywall adjacent to a stud. Placing plastic box in the hole up against the stud. Screwing through the plastic into the stud.
What happens if you replace a metal box with a plastic box?
If you replace an old metal box with a new plastic box in this type of system, you break the ground connection.
How far apart do you staple wires in a junction box?
Many do not, though, and require the wire to be stapled in place within eight inches of the box.
What is a plastic junction box?
Plastic electrical boxes, sometimes called junction boxes, have plenty of pluses, including low cost, convenience, and ease of installation. But they're not the best choice for every application. When plastic doesn't make sense, the standard alternative is a metal box.
What is a new construction box called?
Boxes for new construction are called "new work.". There are also special boxes for remodeling work, called "old work.". These have little ears that flip out to grab the backside of the drywall when the box is screwed in place. Metal boxes also come in old work types, but they aren't always as easy to use.
Can you use plastic threads on ceiling fans?
Although there are some plastic boxes that are designed to support these fixtures, it’s hard to have faith in the plastic threads that support a fixture over your head. For heavy fixtures and all ceiling fans, be sure to use boxes with heavy-duty braces or mounting brackets designed for this purpose.
Do plastic boxes need to be grounded?
Having a nonconductive box is good in most cases, but in some electrical systems it can create a problem. The nice thing about nonconductive boxes is that they don't need to be grounded.
Is plastic cheaper than metal?
Plastic is cheaper than metal. Both are pretty cheap, but plastic wins in most cases. The fact that plastic boxes usually don't need clamps also saves you a little bit more.
Why do you need a weatherproof box?
When installing electrical boxes outside your home, garage, or building, a weatherproof box, when properly connected, seals out inclement weather so moisture doesn't get in and short out the connection. When the outlet is in use and in danger of getting wet, a flip-up cover can be used to keep the outlet and cords unexposed to rain.
What is a single gang box?
Single-gang boxesfor basic outlets and switches. Double-gang boxesfor two light switches or duplex receptacle outlets. Electrical boxes are much more than containers for wiring; they also protect wires and cables from getting damaged, loosened, or pulled apart, all of which can leave you without power or, worse, cause an electrical fire.
Why are plastic boxes bad?
One negative to plastic boxes is their tendency to distort when stressed; and if they're hit hard enough, they can crack. And while the pre-attached clamps are convenient, it's often difficult to remove the cable once it's clamped.
What is an electrical box made of?
Unlike electrical or breaker panels, which are nearly always made of steel, electrical boxes can be constructed of metal or plastic. Depending on the circumstances of how they'll be used, one material can be preferable to the other.
How to contact David Gray Electrical Services?
If you want to learn more about electrical boxes, or to schedule an appointment to have them installed by one of our skilled electricians, contact David Gray Electrical Services online or by calling us at (904) 440-0718.
When to use metal box?
Metal boxes should be used: When metal-sheathed cable or metal conduit is running in or out of the box. For interior exposed application such as in an unfinished basement or mudroom where there's no drywall. You can use a metal box for NM wiring, but special precautions should be taken to ensure proper grounding.
Is a metal box stronger than a PVC box?
When to Choose Metal Boxes. 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!
What Size of Box Do You Need?
The National Electrical Code (NEC) and local building codes restrict the number of wires, devices and fittings that are allowed inside electrical boxes, generally referred to as "box fill." Wires create heat, and an overcrowded box can become dangerously hot. As a general rule, bigger boxes are better than smaller boxes, and you can't go wrong by choosing a larger size of box, provided it will fit your application.
Why are electrical boxes important?
Boxes have two very important jobs: they provide means for securely mounting electrical cables and devices (outlets, switches, light fixtures, etc.) in walls and ceilings, and they enclose the wiring connections to protect neighboring materials and people from ...
How many conductors are in a box?
When a box contains devices, each device is counted as two conductors. Cable or conduit clamps inside the box are counted as one-half or one conductor each, depending on the type. Each "hot" and neutral wire is counted as one conductor, while all ground wires together are counted as a single conductor.
Why is it important to choose the right size of electrical box?
Choosing the right size is important because it's unsafe—and illegal—to cram too many wires and devices into a box. Electrical boxes are used to mount all electrical devices and to contain all wiring connections.
What are standard electrical boxes?
Standard Types of Electrical Boxes. Standard electrical boxes are designed for indoor use in dry locations. They come in several shapes and comprise the great majority of boxes in a household wiring system. Advertisement.
What is an electrical box?
Electrical boxes are used to mount all electrical devices and to contain all wiring connections.
How deep is a pancake box?
Pancake box: Shallow (about 1/2 inch deep) round box for mounting to the surface of drywall or setting into a single layer of drywall.
What Is the Purpose of an Electrical Box?
The most common electrical boxes that you will encounter are rectangular boxes used for wall switches and outlets, square boxes for junctions, and octagon boxes for ceiling or wall-mount light fixtures and smoke alarms. Metal boxes are typically made from durable steel, and plastic boxes are made from PVC or fiberglass.
When to Use Metal Electrical Boxes
Generally speaking, metal boxes are synonymous with durability. If you choose a metal electrical box, you don’t have to worry about bending or warping over time. They can hold strong screws and will never melt if the wiring becomes too hot.
When to Use Plastic Electrical Boxes
Plastic electrical boxes provide a cost-effective and lightweight alternative to metal electrical boxes. And because plastic is a natural insulator, these boxes do not need to be grounded to use them safely with electrical systems.
What to Know About Exterior Electrical Boxes
Running electricity to the exterior of your home provides convenience and flexibility. Imagine how comfortable your patio would be without outdoor lighting or how easy it would be to power wash your home without an external outlet. But running electricity outdoors requires some additional considerations.
The Bottom Line on Choosing the Right Electrical Box
There is a right and a wrong time to use each type of electrical box. And, surprisingly, there is a little more to it than personal preference. Metal boxes which are typically made from steel are durable and heat resistant. They make the best choice for metal-sheathed wiring, metal conduit, and outdoor applications.
Author
Bobby Lynn is the Owner of LiveWire Electrical, a fully licensed and insured residential and commercial electrical company serving Charlotte, NC, and surrounding areas. Bobby has been in the electrical industry for over 20 years and has a vast knowledge of all things electrical.
What are the disadvantages of plastic boxes?
The disadvantages of plastic boxes are their brittleness and wire support brackets. If you look at the box, you'll notice that the device screw holes are also plastic.
What is an octagon box?
Plastic octagon boxes are often used for supporting ceiling fixtures and making electrical connections, but they do have their weight limits. These boxes are usually found on walls and on ceiling for connections and use with light fixtures. The wiring must comply with the National Electrical Code guidelines to ensure safety. Installing light fixtures isn't all that hard with these boxes, but ceiling fans should have a bracketed box capable of holding the additional weight they have.
Can metal boxes take a pounding?
Metal boxes can take a pounding and still function. The plastic boxes sometimes have plastic push-in tabs to hold the nonmetallic sheathed (NM) wire. These tabs serve their purpose, but we’d much rather have a wire connector or a metal clamp with a screw and tighten the tension to hold the wires in place.
Do you need a bigger junction box?
Junction boxes come in many shapes and sizes. Depending on what sized wire, how many wires are in a given box and the number of wire splices in that box, you may need a little more room than a standard box can give you. You may have to opt for a deeper or larger box to accomplish the splicing you have planned. Then again, you may need both a physically larger and deeper box for the electrical job that you are working on.
Do you need a ground wire for a plastic electrical box?
Plastic electrical boxes have their pluses and minuses. Because they are plastic, there is no need to attach a ground wire to it. Since it is made of a non-conductive material, switches and outlets cannot short out if they touch the side of the box.
Is it better to use a metal box or plastic box?
If you have a choice between a plastic or metal box, definitely choose the metal box every time. The plastic boxes are cheaper and easier to install, but it’s not a bad idea to choose quality over price. A metal box will survive a fire, but will your plastic box?
Can you tap a metal box out?
If the metal hole in a metal box strips out, you can just tap it out and it's as good as new. Not so easy with a plastic box. The same holds true for the nail-on mounting brackets. If you hammer the nails carefully and don't accidentally hit the plastic bracket, you're fine.
