Examine the wiring of anything from a light switch to a ceiling fan to an industrial control panel, and you very well might find a metal junction box protecting the wiring. Metal electrical boxes are known for their durability and versatility, which is why you’ll find them in homes, businesses and industrial facilities around the world. However, plastic junction boxes made from rugged materials like polycarbonate are also ubiquitous today — so which is the right choice for your application?
Whether you’re learning the ropes of electrical work or starting a DIY project, it’s important to know when to use a metal junction box vs. a plastic box. Polycase is a leading manufacturer of customized junction boxes for all kinds of applications — from industrial electrical systems to home electronics projects — and we can provide you with the metal enclosure or plastic enclosure that works for you.
In today’s TechTalk guide, we’ll talk about when metal junction boxes are the appropriate choice, and when you should go with plastic junction boxes instead.
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There are two types of junction boxes in common use today: metal junction boxes and plastic junction boxes. Both have their own advantages, and both are useful for certain applications.
For many applications, the biggest advantage of a metal junction box is its durability. Metal junction boxes can withstand a huge variety of adverse environmental conditions, including crushing impacts, open flames and extremely hot or cold temperatures. They also serve as natural grounding points for metal-sheathed wires and other components that require electrical grounding.
Plastic junction boxes are generally less expensive and may be easier to work with. However, some plastic junction boxes are less resilient than metal boxes, so they may not be the ideal choice if you need maximum protection and maximum durability from your junction box.
In the next sections, we’ll look at some common scenarios for when to use a metal electrical box and when you should use a plastic junction box.
Need a Metal Enclosure? Polycase Has You Covered!
You should consider using a metal electrical box if:
These aren’t the only circumstances in which you should choose a metal junction box, but they’re some of the most important. If you’ve decided a metal junction box is the right call, see our guide to metal electronics enclosure options for some great choices.
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Conversely, there are also some reasons you might choose a plastic junction box for your project instead. A plastic electrical box might be a better choice for your application if:
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The ultimate authority, of course, is the National Electrical Code. Always verify the relevant NEC rules on enclosure materials and design before choosing your solution — or consult a qualified electrician. Ready to learn more? Check out our quick-start guide to NEC junction box rules here, as well as our enclosure materials selection guide!