One way to have an electrical enclosure to have flame-retardant properties is by using ABS plastic in manufacturing and molding enclosures. It comes with several benefits. If your application requires a flame-retardant enclosure, it is important to identify the right enclosure that would definitely suit you needs. In addition to this, it is important how the makers of this type of enclosures utilizes the flame-retardant properties of some materials that they use.
The Underwriters Laboratories or UL, is the highly respected board of organization that does tests for safety compliance of products. It is located in the United States. This organization are having thousands of products tested (including accessories) each year to make sure that these products comply to several safety factors. For example, they have to make sure that companies follow protocol for electrical shock safety.
All of the electronic enclosure makers (including manufacturers of electrical component) can only have UL ratings on their products if they comply to rules and regulations and if they are completely tested by Underwriters Laboratories. This organization are maintaining a very high standard parameter for testing and scoring of product quality. They created a universal standard that are now followed in several countries. This helps customers to gage the products’ safety capabilities.
With this in mind, the highest UL rating has for flame-retardant plastic is UL94 5VA. What this means is if the plastic enclosure made of this material is exposed to open flame, it will not have a burn-through hole. It will not develop any holes if in case it is was set on fire and it will not have dripping plastic because of melting while burning. In summary, an electric enclosure with this plastic rating will protect any electrical equipment against a fire.
To guide you thoroughly, here are the following chart that gives a set of UL standards in terms of flammability of plastic materials. These materials are being utilized in making electronic enclosures:
5VA (Surface Burn): This rating means that the burning on plastic will immediately stop within 60 seconds. The plastic specimens under this rating have not shown a burn-through (no hole) after five applications of five seconds each for each flame. In this case, this is the best rating because it has the highest flame-retardant UL94 rating.
5VB (Surface Burn): This rating means that the burning on plastic will immediately stop within 60 seconds. However, unlike the previous rating. This one will have a burn-through hole.
V-0 (Vertical Burn): In this rating, the burning will stop within 10 seconds time frame. This is shown after two applications of ten seconds each of flame. No flaming drips are allowed for this kind of rating.
V-1 (Vertical Burn): This rating means that the burning on plastic will immediately stop within 60 seconds. Like the previous rating, no flaming drips are allowed.
V-2 (Vertical Burn): This rating means that the burning on plastic will immediately stop within 60 seconds. Unlike the previous rating, flaming drips are allowed.
H-B (Horizontal Burn): Among all the ratings, this is considered the least flame-retardant of all UL94 ratings. However, H-B rated plastic materials are proven to be “self-extinguishing” in case of fire.