ktesibios
Worthless Aging Hippie
- Joined
- Feb 23, 2002
- Messages
- 1,493
About 15 years ago I was working at a large recording studio in Center City Philadelphia. We had two separate electrical services coming into the building, a 200A 120/240V service which supplied the lighting and audio equipment loads and a 600A 120/208V 3-phase service which supplied the air conditioning systems.
One day, the latter went dead. Not a volt was entering the building and not a bit of A/C did we have. This was a real problem, because a typical studio control room is a sealed, heavily insulated box containing 5 to 6 kW of high-tech space heaters. When the A/C to a control room failed, the temperature in the room would hit 100F in less than an hour and we'd have to shut down all the gear in the room.
The electric company sent out a crew, and they quickly determined the cause of the failure.
About a week before the power went down, the city had installed a street sign on the corner outside our building. It turned out that they had driven the butt of the pole right through the underground conduit carrying our A/C service. It had taken a few days for the damaged conductors to burn through, so the problem wasn't immediately apparent.
When the electric company guys dug that pole out of the ground, the bottom of it was blackened and scarred from arcing. The chances are that at least some of the time that pole was "live" with respect to ground, and anyone who happened to lean on it at the wrong time could have gotten a nasty surprise.
The real kicker is that it wasn't a private contractor but the city government's Streets Department who had pulled off this remarkable feat of dumbnitude.
One day, the latter went dead. Not a volt was entering the building and not a bit of A/C did we have. This was a real problem, because a typical studio control room is a sealed, heavily insulated box containing 5 to 6 kW of high-tech space heaters. When the A/C to a control room failed, the temperature in the room would hit 100F in less than an hour and we'd have to shut down all the gear in the room.
The electric company sent out a crew, and they quickly determined the cause of the failure.
About a week before the power went down, the city had installed a street sign on the corner outside our building. It turned out that they had driven the butt of the pole right through the underground conduit carrying our A/C service. It had taken a few days for the damaged conductors to burn through, so the problem wasn't immediately apparent.
When the electric company guys dug that pole out of the ground, the bottom of it was blackened and scarred from arcing. The chances are that at least some of the time that pole was "live" with respect to ground, and anyone who happened to lean on it at the wrong time could have gotten a nasty surprise.
The real kicker is that it wasn't a private contractor but the city government's Streets Department who had pulled off this remarkable feat of dumbnitude.