As enclosure specialists we are often asked which is better metal or plastic for electrical cabinets? Each material has its own strengths and weaknesses, and which material you use for your next electrical cabinet enclosure project will depend largely on what you need it for and how many you are looking to produce.
But before we look at the pros and cons of Plastic v Metal for Electrical Cabinet Enclosures, here is a brief overview of what an Electrical Cabinet Enclosure is.
What is an Electrical Cabinet Enclosure?
Enclosures acting as a case or cabinet for electrical equipment come in all shapes and sizes with a variety uses from roadside to in food production facilities, pharmaceutical and medical equipment.
The enclosure or casings main purpose is to keep the electrical equipment neatly and safely contained thus protecting people from high-voltage electrical elements that could potentially injure and also offer protection from the elements.
Pros for plastic enclosures:
The term “plastic” is a blanket term that typically covers many different materials, including polycarbonates, ABS and HIPS.
- Plastic electrical enclosures are less expensive and lighter than metal.
- As most plastics are electrically insulating whereas metals are good conductors so plastic electrical boxes, unlike a metal electrical box, would not need to be grounded. Grounding an electrical box takes more time
- Also, often plastic electrical enclosures have mounting pillars integrated into them which can make the installation of a plastic electrical enclosure easier than a metal one.
- Lastly plastics have a clean, smooth surface that tends to be easy to clean, look professional and work well where they have high visibility and aesthetics are important.
- They are also easy to modify by cutting holes which is often required with electrical enclosures to ensure they can do and hold what you need them to.
Cons of plastic enclosures
Plastics has limited chemical resistance relative to metal. It is not rated for use with solvents or alkalis, but it is compatible with mild acids. Some polycarbonates are not ideal in outdoor situations and can become brittle with extended exposure to sunlight, which can compromise it.
Also, relative to metal plastic doesn’t withstand blunt force trauma as well. For example, metal roadside enclosures are more robust when it comes to with a speeding car or truck.
Pros for metal enclosures
Metal is fire resistant and the 17th Edition Amendment 3 of BS 7671:2008 which came into effect in July 2015 and stressed the importance of enhanced fire risk protection. It brought into effect from 1st January 2016 the switch to metal clad consumer units for all new electrical installations and designs.
Metal is also stronger and would barely be marked by the IK10 test (the maximum specified in EN 62208 2011) whilst a typical plastic enclosure would only pass IK 7 or 8 (equivalent to hitting them with a big toffee hammer).
Cons of metal enclosures
They tend to be more expensive and heavier than plastic enclosures. Metal enclosures also have sharp edges and always have to be painted which adds to the cost of the enclosure.
Metal can also be difficult to work with and shape. Shaping a metal part can require die work, welding, grinding, rework, or bending to achieve design specifications and desired look which can be limiting. Metal also needs to be earthed given its conductivity which can present safety issues.
Plastic v Metal for electrical cabinet enclosures conclusion
It seems that it is entirely dependant on the application and your budget as in reality both are safe for electrical application. Questions around the application, quantity and the environment that it will be used in will all influence the decision made.
If you would like to discuss any aspect raised in this article please call the CDT, the UK’s leading plastic enclosure experts on 01280 845530.