Flame Rated Plastic Electronic Enclosures for Your Safety, Part One

Example of Polycase enclosure information with flame rating information highlighted (our AG series)

My puppy, a one-year-old black lab, has started chewing through anything with a cord. He’s sly about it and doesn’t get near them when I’m in the room, but rather waits until I’m asleep. While it’s merely annoying that the curtain pull is now 2 separate cords, it’s outright dangerous when, for instance, he decided the power cord on the space heater would be a tasty midnight snack. This new “game” of his has me thinking about how safe my house really is for a puppy, and what types of precautions I can take to keep him safe.

Almost everything you buy nowadays comes with safety guidelines: Don’t use the hair dryer in the bathtub. Keep toys with small pieces away from children under the age of 3. Contents under pressure; do not puncture.

Polycase puts safety first by molding our enclosures with UL certified material. Most of our enclosures meet UL’s best flame rating of 94-5VA. Ratings for specific enclosures can easily be found on each of our product pages on this website. We use premium materials so your end product can meet the needed UL requirements. Information is provided to help you select the right enclosure at the start of your design process.
The flame rating is used to determine the appropriateness of using the plastic enclosures as part of a device and supplies safety guidelines as to the environment in which the enclosure can safely be used.

Let’s look more closely at what the flame rating is and how it is determined. -

The UL flame rating of UL94 is a measure of the flammability of the plastic material. There are two tests that help determine this measurement. The first measures the enclosure’s ability to extinguish flame once it has been ignited. The second determines the ignition resistance of the enclosure to electrical ignition sources. The rating is determined based on a variety factors and scored accordingly. A few of these factors are:

•    Burning rate measured in number of inches/minute based on thickness of material.
•    Specimens must stop burning before the flame reaches a specified mark.
•    Specimens must not burn with flaming combustion for more than a specified number of seconds.
•    Specimens must not drip.
•    Specimens must not be destroyed in the area of the flame.

The tests are more fully described at the link below:
http://www.fire-testing.com/html/instruments/ul94ad.htm