"Tony Hwang" wrote in message
news:bRaSj.105280$Cj7.46240@pd7urf2no...
David Nebenzahl wrote:
On 4/30/2008 6:46 PM Tony Hwang spake thus:

Boden wrote:



The purpose of the breaker is to protect the wire from excessive
current. So long as the wire gauge and breaker capacity are matched
properly the size of the load is immaterial.

Hmmm,
Really? wire is link between breaker and the load. Current flowing on
the wire is depending on load. You are trying to say breaker only
protects wires, nothing to do with the load? Does not make sense to me!


The point is that the tripping point of the breaker depends on the
maximum capacity of the wires, *not* the load. Think about it and you'll
see why this is so. I suppose you could say that it's more important to
protect the wires, since they're what can cause fires if overloaded.

So if you have a device that normally draws, let's say, 1 amp on a 20-amp
circuit, and the device overloads and draws, let's say, 10 amps, that
device is going to burn up without tripping the breaker. No way to avoid
it, unless the device itself is fused.


Hmmm,
Who in right mind would configure/install a wire/load like that? All 3 is
on a closed loop. They all interact together.

Most recepticals in houses are wired with either 15 or 20 amp breakers.
Look at all the devices you have in the house and see how many are plugged
in that only draw a few amps.

As said above , the sizing of the breakers and wire is such that the wires
are protected from getting too hot and causing a fire in the wall. The
devices plugged into the recepticals should be fused to protect them.