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About:
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The first electrical distribution system provided direct current to residential and commercial customers in lower Manhattan. It was built by Edison Illuminating Co., beginning in 1882. Earlier in the century, telegraphy networks had become widespread, and ampacity, over-current protection and similar principles had been worked out. Fuses and even circuit breakers were available early in the nineteenth century, and Edison’s crews were able to create relatively safe installations. This is not to say that electric shock fatalities and electrical fires did not occur.
For homeowners and small commercial operations, it was a new technology, not without risks. But the advantages of incandescent over gas lighting (which also had hazards), was immense, so the demand for electrical service was great.
Doing premises installations, electricians quickly realized that they could make use of existing gas piping to route wiring throughout buildings. They could install numerous concealed wire runs without tearing up paneled walls and cutting into stamped-tin or plastered ceilings. Moreover, the repurposed metal piping provided excellent protection for the conductors and would contain thermal energy that might result from line-to-line arc faults.
This wiring method had drawbacks. The existing gas piping did not have pull boxes or large-radius bends, so when installers encountered an elbow, the pull stopped abruptly. Additionally, because there was no general consensus on grounding (some early codes prohibited it altogether) there was the possibility that abraded electrical insulation would permit an entire run of metal pipe to become energized.
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