Open Neutral and failed transfer switch

wolfe10 wrote:
But, an open neutral could sure take out appliances!

OH YA! A bit off topic, but related. I DJ in my spare time, and have my DJ setup in a 2-part rack (mixer, CD players, EQ for mic, etc). One unit I have installed is a Furman Power Conditioner with LED voltmeter.

I was DJ'ing a wedding a couple weeks ago on the beach at a local resort. I plugged the rack in and powered it up so the CD players could clean any condensation of the laser lenses while I was finishing setup. A minute later I come back to find the entire rack off, and only the power switch, Protection OK, and Extreme Voltage lights on the Furman illuminated.:h

Figuring that I'm at the end of a LONG power cable and housekeepers in the resort were doing synchronized vacuuming (causing massive voltage) drops, I reset the Furman. Minute later I hear it click - again, everything off.

Get a hold of the maintenance guy, and he comes down. He thinks it's the power bar I'm plugged into (so the tent lights could run as well). But then, as we're talking I see the voltmeter light right up for about a second prior to the CLICK and the rack shuts down (all but the top red LEDs were already on). Hmmm, so the Extreme Voltage indication is for over-voltage! That's odd.

Turns out I'm on a 220VAC feed from the nearby cabin, and am drawing using just 1 leg. WE switch legs (another outlet), and the voltmeter is now down to the first top yellow LED. Better, but the voltage proved to still be a problem during the show. Can we saying EMBARRASSING when the bride/groom song cuts out 30 seconds in due to the Furman doing its job?!?!?!:E

Moral of this? I suspect there was a flaky neutral somewhere between the pole mounted transformer and the box I was plugged into (and I told the guy this too). The maintenance guy told me the power company had been fooling around on the poles recently so I suspect they inadvertently screwed up the neutral wire coming off the transformer. Of course, being right on the beach, salt-air corrosion might have played a role too.

SO yeah, an open neutral can and will send 220VAC to your 110VAC gear if you're not careful.

Cheers!