On 10/31/2013 11:36 AM, Pavel314 wrote:
Our greenhouse heater wore out after a number of
years so we bought a replacement. It's essentially
the same heater except that the new one is a different
color and the plug is a different configuration. The
old one has one round pin and two flat blades, with
the blades at an angle to each other and above the
round pin. The new one also has one round pin and
two flat blades but the blades are lined up with
each other, so I have to replace the receptacle
with one that matches the new plug. Not a major
project, just a minor annoyance and expense.

I've seen other 220 volt plug configurations;
some have an L-shaped blade instead of the round pin,
others have four blades in a circular pattern which
lock when turned, etc. Is there any practical reason
for all these variations?

Paul

Some are based on different ampere capacities.
In 110 volt plugs, a config like this:

| |
O

is 110 / 120 volt, 15 amp.

Plug like this:

- |
O

is 20 amps.


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Christopher A. Young
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