Fire resistant resistors?

Unknown

How do you determine if the resistors you buy are fire resistant?· I bought some cheap resistors online and then I learned they could be from another country and then I learned I could buy fire resistant resistors.· How do you tell and can you always know?

http://en.wikipedia.org/wiki/Fire-resistance_rating
http://www.freepatentsonline.com/3804669.html

Leon

Apart from testing them, you can't. Fire-resistant resistors sold in the US will presumably have the UL mark on them, or it will be in the spec. If you need fire-resistant parts you should buy them from a reputable supplier like Digi-Key or Farnell, and check the specification.

Leon

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LoopyByteloose

I've never consider the need for 'fire resistant' resistors, but I take the wattage ratings rather seriously. I suppose there are environments where fire resistant is an added necessity, but staying well within the rated wattage for the resistor will eliminate 99% of your worries.

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Ain't gadetry a wonderful thing?

aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan

Manetheren

I would assume that any emergency type of circuit would require fire resistant resistors.

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Tia'Shar Manetheren

Carl Hayes

I would say that it depends upon whether you need them to be resistant to cannon fire, or only, say, to rifle fire.

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· -- Carl, nn5i@arrl.net

LoopyByteloose

There are those other devices - fuses and circuit breakers. The truth is that fire is far less common in a digital environment than an analog environment.

At 3.3 - 5.0 volts, there isn't much of a fire risk. Of course if you are building a hefty power supply or driving horsepower multiples of motors, use the fuses and circuit breakers. If a circuit calls for a 3 watt resistor, use a 5 watt.

What the heck is an 'emergency type' circuit? A hazardous environment is more likely to call for fire prevention.

I would suspect that fire retardant resistors are more appropriate for highly combustible environments and atmospheres - like in a gas station. These applications have specialized ratings and go through extensive testing toward certification. Just adding the resistors isn't going to get you a certification for safety in such. The whole process is expensive and meant to be so that well heeled corporations can dominate the market.

Regarding 'combustible environment'.... that was the reasoning behind a metal chassis and metal conduit. The chassis and conduit are intended to contain any fire created by an electrical failure. The fuse is suppose to eventually make the system fail into an 'off mode'.

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Ain't gadetry a wonderful thing?

aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan

Post Edited (Loopy Byteloose) : 10/14/2009 2:29:09 PM GMT

Humanoido

if going from out in instead of in out in the direction fire retardation, a piece of fiberglass tape is an ideal insulator. This is often used in MOV circuits for safety reasons. Of course, component heat dissipation must be kept in mind. Not only will it keep heat out, it will keep internally generated heat in.

humanoido