Zinsco, yikes!! Almost as bad as FPE....

Not sure if Code allows it, but a few years back I did a refit on a screening room where the audio racks were serviced by 5 20amp breakers (on a 3-phase panel) with ONE #10 neutral for all 5 circuits!!! The client was wondering why the sound system had a massive hum and why he'd been replacing burned-out amplifiers every few months.
(edit: There were NO loose/bad connections, which was my first thought.)
To stir the pot again (see "Panel In Bedroom" thread) [Linked Image] , I am of the school of NO SHARED NEUTRALS UNDER ANY CIRCUMSTANCES!! The cost of the extra wire is NEVER that great, compared to the potential problems.

After I had the EC pull in the proper number of neutrals and wire the rack recepts correctly, the system was quiet and no more burning amps.

[This message has been edited by mxslick (edited 03-10-2005).]

Stupid should be painful.