environmental pollution degree 是在UL840里对PCB板上电气间距要求的一个分级，LED 灯泡可以参考UL1993中的这段条款：
9.8 When applying the requirements specified in UL 840 to determine environmental pollution, the device
can be evaluated with different environmental pollution degrees. The following conditions apply:
a) A device marked for damp or wet use shall be exposed to environmental pollution degree 3.
b) A device intended for dry locations shall be exposed to environmental pollution degree 2.
c) The portion of a printed wiring board covered with a potting compound or a conformal
coating that complies with the requirements in Conformal-Coating Tests, Section 32, shall be
exposed to environmental pollution degree 1.
发表于 2012-1-27 17:27:22
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