Electrical Tip Of The Day

I have an electrical story. About 40 years ago, our firm was working on an air conditioning upgrade for an old middle school. The project Electrical Engineer was walking the site with us. Out in school yard, there was a concrete slab with a pad-locked metal door on it. The door led to some kind of electrical vault. My boss and the EE were older, so I climbed down into the vault with a flashlight. I can still remember my first words, "Jesus Christ!"

On the opposite wall, about 6' away, were three, horizontal, shiny copper bars (480V), totally bare and exposed with nothing in front of them. I felt very uncomfortable and stayed glued to the wall opposite the bus bars, and quickly got out of there. The EE said that installation was no longer legal, and he would replace it.

Can you imagine if some kids would have cut that lock, and gotten down into the vault?

Around here there are several metal supply outfits with large traveling cranes. These are a huge cross beam that runs on tracks on the sides of the building, with a powered carriage that runs crosswise on the beam. How do they get their power? BY BARE MULTIPHASE BUSS BARS which have sliding? rolling? contacts. These bars run horizontally along one side of the building wall

Here's the thing. If some worker, "not thinking" was to lean a 20' piece of tube/ pipe/ material against the wall vertically in certain "accessable" spots, it could VERY easily contact those rails.

These work like third rail train/ subways, or overhead electric powered bus/ trolleys