"mmc" wrote in
ng.com:

We had an issue with AC problems at our marina. When the demand was
high, certain 110v items wouldn't work or would work right - seems the
power thinned out to the rest of the boats on our circuit. Obviously
I'm not an electrician.


That sounds like a loose neutral connection. That forces the current from
one load going into the neutral bus to go out to the other phase of the 240
through the loads on the other side of neutral. When something switches
off on the other phase, your side loses voltage because they are in series
across 240VAC. When a motor starts on one side, the other side bears the
brunt of most of the 240VAC as the motor is drawing very heavy current.
This will blow out anything on the side opposite the starting motor with
overvoltage...lights blink very bright, fuses in electronics blow en masse
trying to protect their hosts.

Loose neutral is very dangerous for everything hooked up. Any time you see
lights suddenly get BRIGHTER for an instant it's almost always loose
neutral connections to the power grid.