I've heard several references that doorbell transformers cannot be installed inside the main panel due to 110.3(B). Makes sense.
However, what about the fact that doorbell transformers usually have threaded collar and a nut to mount them to a spare knockout? As far as I know these are ok to affix to the OUTSIDE of the load panel. If that is the case, then how does that square with 110.3(B)? If its on the outside surface, do we feel that 110.3(B) does not apply or do the panel manufactures allow for this in their UL listing?
Thanks!
However, what about the fact that doorbell transformers usually have threaded collar and a nut to mount them to a spare knockout? As far as I know these are ok to affix to the OUTSIDE of the load panel. If that is the case, then how does that square with 110.3(B)? If its on the outside surface, do we feel that 110.3(B) does not apply or do the panel manufactures allow for this in their UL listing?
Thanks!