A junction or electrical box is an essential part of every property, however big or small. Your home’s electrical system is dependent on your electrical box. Each enclosure will house several different wiring connections for a wide range of electrical devices and applications.
Examples include fixtures, outlets, transition wires, and switches. Junction boxes are designed to protect wires and cables from external damage. They will also be protected from short-circuiting and other issues that may trigger electrical fires or hinder performance or functionality.
Choosing between a plastic electrical box and a metal electrical box can be daunting, but it doesn’t have to be. For many people, the choice really comes down to personal preference. For some, the deciding factor may come down to convenience or the cost of the item in question.
However, there may be cases where the choice is quite clear. Grounding, for example, may serve as the determining factor. Most people who prefer to take such matters into their own hands will opt for a plastic junction box.
As for electricians, they will use both plastic and metal junction boxes, as the situation dictates. Here, we will discuss both metal and plastic junction boxes and their pros and cons so that you can make an informed decision.
Metal Electrical Boxes
Metal junction boxes are known for their impressive durability. A metal junction box will be able to withstand virtually any environmental condition, however harsh. Examples include extreme cold or heat, crushing, and open flames.
Moreover, a metal electrical box will serve as a natural grounding site for wires that are insulated with metal. Many other components that are electrically grounded will also be covered. In fact, local building codes in certain jurisdictions may require that you use metal electrical boxes.
As mentioned, metal boxes are more durable than their plastic counterparts. They have the added benefits of providing superior performance and a longer lifespan than plastic boxes.
If you have sufficient training to work with metal boxes, then make sure you wear safety gloves before you get started, as the sharp edges may cut you if you work with your bare hands.
Plastic Electrical Boxes
Plastic boxes have the benefit of being very user-friendly. They are lightweight and easy to deal with. They are also quite cheap, which is why many laypersons prefer them over their metal counterparts. If you want to punch holes in them, then you can do so on the sides and the back with relative ease.
Note that plastic boxes can melt when they are exposed to elevated temperatures. However, they will not conduct electricity. It should also be noted that most plastic electrical boxes have wire clamps that are integrated into the unit. The cost of your project will go down as a result.
If you need to perform an outdoor installation, then we would strongly recommend that the box that you choose is not only weatherproof but also made with aluminum, as this metal will help protect your wires from moisture-based damage.
The Benefits of Using Plastic Electrical Boxes
Plastic electrical boxes are the better choice for domestic projects. They are lightweight, economical, and user-friendly. For instance, you don’t have to worry about grounding when dealing with plastic electrical boxes. You also won’t have to be concerned about them conducting any electricity in the event that they come into contact with a live wire.
Grounding can take quite a bit of time to configure and is usually best left to the professionals. For these reasons, most electrical contractors will go with plastic electrical boxes over metal electrical boxes whenever practical.
Plastic electrical boxes come equipped with clamps or mounting nails that are pre-integrated, which is yet another benefit. However, the nail brackets are quite fragile and may break off during a replacement or installation project, making them virtually impossible to install.
When is it best to use metal boxes?
Metal boxes are far more durable than plastic boxes. They are also fireproof, and you won’t have to worry about them bending or fracturing. You also don’t have to worry about them being crushed or warped.
They will not melt even when exposed to high heat. Hence, they are the preferred choice for most electrical wiring applications. When a metal-sheathed cable or a metal conduit is run in and out of the box, an electrical box that is composed of metal is actually mandatory.
In addition, if you have any exposed interior applications, such as conduits in mudrooms that have incomplete drywall systems, then metal is the preferable choice. You should opt for a metal electrical box for incomplete or unfinished basements as well.
You can, in fact, use a metal electrical unit for wiring that is non-metallic in nature. However, sufficient grounding must first be completed before any work can take place.
For most people, choosing between plastic and metal electrical boxes really comes down to personal taste. Some may simply have a tight budget and may have no choice but to go with a plastic electrical box.
A plastic electrical box may be more convenient as well since no grounding is required. If grounding is required, though, then going with a metal electrical box is usually the preferred choice. If you have an existing metal electrical box, then have an electrician examine it. They will let you know if you should replace it with a plastic electrical box.
Interestingly, metal boxes were actually considered the gold standard for several decades. However, the advent of easy-to-use and inexpensive plastic boxes made some homeowners replace their old metal boxes with new plastic ones. If you have any doubts, then simply call a local electrician so that they can help you make an informed decision.
Stephanie Alexander is a blogger. She is currently a blog manager, predominantly based in the Greater Toronto Area, managing content for a few different blogs for different clients with wildly varying information needs or topics of interest. She likes to research topics mainly related to home improvement. Most recently she graduated from the University of British Columbia with her Bachelor’s in Business Administration and Creative Writing with Honours.