In preparing to design a show in a space I'm not familiar with, I was trying to troubleshoot/confirm the functionality of a handful of dimmers. Of the six that I was told didn't work, I discovered that four of them did actually seem to work (have to wait until show time to see they are actually trustworthy, but they did pass initial inspection). One seems to have a short either in the line or on the dimmer end. The other simply doesn't turn on either by the manual switch at the dimmer pack or from the control system.
I noticed something odd though as I was testing. In checking the dimmers, I turned my Extech 411 multimeter's dial to the 200 mark with the "~" above it for AC voltage, and I get a number. I was getting a voltage reading between the hot and neutral even though the dimmer was not on, and when I plugged a load into it (a 6" fresnel), the load did not turn on.
I got this result with working dimmers and with non-working dimmers. If I turned the breaker off at the pack, I would get a voltage reading of 0. The packs are 2 24x10amp CD-80 cabled to boxes of 3 circuits in the grid. Any ideas about what is going on? Am I doing something wrong, or is it something else? It seems to me that if there is no current (as must be the case since the light didn't come on) shouldn't there also not be a voltage reading? I don't specifically recall what the voltage reading was when the circuit was hot, but I was getting readings of between 108v and 114v on various circuits.