The Power of Darkness
As an electrical designer at a NASA center, I once got a phone call from a user who had contracted for a turnkey installation of large above-ground fuel oil storage tanks for several boilers. He was complaining that his new tank pumps worked well, but would only run at night. In my mind, there was only one thing to explain the situation. Sure enough, a field investigation revealed that the contractor had wired the 480VAC motors from branch breakers in a 480Y/277VAC panelboard. The source was a lighting panel for outdoor 277V flood lighting. The feeders for the panel were made hot with a large contactor that had a coil activated by a photoelectric cell. This is still my favorite story to tell around the office.
Common Sense Alert
While working as an energy manager for a public school, I was called early one morning and asked to meet the head custodian and fire department personnel at one of our schools. They had been unable to silence a fire alarm that had sounded shortly after the first employees had entered the building, and were frantic to silence it before the students arrived. Upon entering the school building, I heard the ear-piercing siren blasting throughout the hallways and understood their concern. While joining the fire chief and head custodian to inspect the fire panel, we found the panel display reading, “SYSTEM NORMAL.” I smiled and then asked the head custodian to follow me to the main entrance. Once there, I asked her to enter her security code into the keypad, thus canceling the security alarm.
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