On Wednesday, April 14, 2021 at 1:57:18 PM UTC-4, Ralph Mowery wrote:
In article ,
says...

Many primary-feed industrial locations ran at 480/277 for lighting and motors. I remember when I was in school our drafting studio was in a former factory right on the Schuylkill in Center City. Wallplate voltage was 130V, lighting was 277, and even the ceiling fans and exhaust fans were 480V. What made it even more interesting
was that the primary service to the building was 4-wire, 2-phase converted to three-phase using 'Scott-Connected' transformers, AKA 'Scott-T' transformers. https://en.wikipedia.org/wiki/Scott-T_transformer

In the studio, there were all kinds of warning stickers on the receptacles stating that they were at an actual 130V. And for those of us with drafting lights, lamps were supplied.



I worked in a large plant as an electrician/instrument technician.
Dealt alot with the 480 3 phase motors and heater circuits. We fed the
floursescent tubes with one phase to neutral for 277 volts. We did
reduce the voltage to 120 volts for the common recepticals.


The manufacturing plant I worked in had 277V for lighting circuits, and somebody miswired the outlet in my office to that circuit.

The custodian burned out three vacuum cleaners in that office, I found out later.

We'd never have known except I had to hang a picture or something and I brought in my own drill. It ran way too fast and I put a meter on the outlet.

Same plant, I got a good tingle connecting computer network cables. They were shielded bi-ax, and the connectors made good contact with my hands. The PC at one end of the line was connected backwards so chassis was hot instead of ground, but further down the line the coax was grounded to another PC. So trying to connect the two, with one cable in each hand, I completed the circuit.