So the question is:
Can/will dust build-up on a dimmer module (assuming dimmer, phase control) cause overheating to such a degree that it leads to a noticeable voltage drop at the fixture?
Thoughts, anyone?
Simple answer, no.
Longer answer. While yes, it is possible that dirty conponents and connections can cause
voltage drops, but let's be honest, there are only a few parts in the
current path from
feeder to load and if those parts are dirty enough to cause a
voltage drop, they are also emitting
smoke burning the dust and dirt off.
Power cubes or SCRs/Triacs and
circuit breakers are not affected. Only chokes are left and they would get so stinkin' hot [literally] that this would be a larger issue than
voltage drop.
Now, what was not mentioned was
voltage drop due to loose connections. While not related to dirt, thermal cycling can cause feed and load screws to gradually loosen and copper
wire can also thermal flow inside these connections. Regular tightening or torque checks on said fasteners [when tension clamps are not used] should reduce or eliminate
voltage drop over these connections. Lack of maintenance can eventually lead to
conductor failure.
BTW, just looking at connections inside
dimmer racks and ignoring connectors in circuits strips and boxes is an oversight.
Next you'll ask me how often to check tightness. Not sure I can give you a direct answer as it greatly depends on use of the
system. The colleges and municipalities that perform this maintenance do it about every other year. There is another option which is to use a thermal imaging camera to look through panels to see if any wiring connections are heating up [and therefore are loose]. Unfortunately, this means you have to run loads on every
circuit [not how we usually work] and seeing inside
dimmer racks is usually difficult.
Maybe there is something I'm blatantly missing, but I can't think of a reason why dust and dirt would create a
voltage drop. Wait, maybe I've been thinking exclusively of digital dimming. It will take me some time to run through my brain catalog to think of how dust could create
voltage drop issues in analog or even linear autotransformer dimmers. Goodness, I still can't think of why. Maybe JD knows?