Edison had chosen place the distribution system underground,
and although this greatly reduced the risk accident, it
increased costs and made vital part the system vulnerable
to the action corrosion and decay. This was
pumped into metal pipe containing the rope-covered copper
conductors.
The first electrical wires went uninsulated; they were
simply attached wooden carriers even gas fittings! The
underground mains the Pearl Street system employed an
asphalt-linseed oil-paraffin wax-beeswax compound.^ The
electrical lighting companies experienced many problems with
insulation wires, both above and below ground, and needed a
better insulating material. Conductors inside houses and offices were covered
with either paper, cotton, shellac, rosin, parafin wax.1
SIDEBAR 5-1
THE INSULATION PROJECT
The development better insulating material illustrates
the problems emerging between laboratory and electrical
companies. Insulation the copper wires conducting the
electricity was unglamorous, but vital part the
system— its performance under difficult operating conditions
helped determine the reliability and economy the system. John Kruesi the Edison Machine
Works commissioned the development work, asking Edison in
August 1887 find insulation that was waterproof, fire
