UL认证

大家好,今天小弟接到一份资料是关于UL认证方便的,现在回复如下:请问哪位大虾能讲讲具体的CL和CR代表什么意思,谢谢!
6.     {Supply board: BSFL} The distance inside of transformer T101: TSRL101 is failed.

        - measured working voltage: 470Vp / 293Vrms

        - required distance: cl. = 4.2mm / cr. = 6.2mm

        - measured distance: 5.5mm for both cl. and cr. (failed)

        - See attached photo.
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