Re: Who invented the circuit breaker?

Hi Lauren,

I also had difficulty finding the one individual responsible for the
development of the circuit breaker. This suggests that probably many people
were involved in the development or that many people came to the same
conclusion around the same time. However, I did find numerous patents on
various circuit breaker designs at the US Patent and Trademark Office
website:  http://www.uspto.gov/

Circuit breaker design is governed by several factors such as, current
capability, interruption time, and means of reset. It seems that circuit
breakers began to appear as soon as electric power distribution was
developed on an industrial scale. This is roughly around the latter part of
the 19th century or the early part of the 20th century. Improvements in the
first half of the 20th century centered around current handling capacity
(for a given size) and reduced interruption time. Interruption time prior
to 1926 was about 45 cycles, or about 0.75 seconds. In the 1960s, two cycle
circuit breakers were available. Shorter interrupt time results in less
stress on other components of the power grid.

Household circuit breakers are available in two varieties: standard and
ground fault interrupt (GFI). Standard breakers are designed to minimize
the risk of fire, whereas GFI breakers are highly sensitive devices
designed to reduce the risk of electrocution. Standard breakers employ
techniques that are almost 100 years old, but GFIs are modern, solid state
devices. GFIs are commonly used in areas where people, power, and water are
in close proximity. Bathrooms are a common example.

In the old days, circuit breakers were manually reset. In the case of
electrical power distribution, this could mean hours before power was
restored. Many of the breakers used today will attempt to automatically
reset in the event of lightning strikes or other short term overloads.
Household circuit breakers tend to be manual reset for reasons of low cost
and safety. The trend in power distrubution is to efficiently monitor and
control circuit breakers from a central location. Power utilities today use
sophisticated circuit breakers that can report their status over power
lines, telephone lines, or by wireless means. Many utilities can monitor
the status the grid and circuit breakers over the Internet. Technicians at
a central facility can monitor where breakers have tripped and attempt to
reroute power through other segments of the grid. They can also reset the
breakers remotely, significantly simplifying the task of restoring power. Of
course, downed power lines and failed equipment still require linemen in
the field to repair the damage.

I hope this answers your questions!