wrote in message
...

When I was done, about 2 hours later, I turned off and unplugged the
heater. To my surprise, the plug was warm, not hot, but definitely warm to
the touch. I took a closer look and realized that the prongs of the plug
were badly tarnished/corroded. An even closer look showed that the
insulation on the power cord itself was badly cracked and falling off(from
overheating maybe) for the first inch or so where it comes out of the plug.


Yow! I've had a similar experience with a space heater and it's why I often
use two of them set to the low power settings warm a room. (Buying an extra
unit is a lot cheaper than dealing with a fire.) I have also put the space
heaters I use regularly on AFCI outlets in the hope that they will detect
and interrupt the arcing that usually causes cords to melt (and worse)
before it starts a fire. While most outlets are rated for 15A and some even
20A, I've found that pulling that much current often leads to the kind of
problem you experienced.

When I used to run the workshop heater at 1500W I melted a powerstrip and a
six way outlet whose internal "bus bar" was a thin piece of copper strip
connected by a pop rivet. A stinking pop rivet that wasn't crimped tightly
enough to even keep the two strips in good contact and that melted down from
the current passing through it. That's when I decided to get a second space
heater ($15 at TruValue) and distribute the load between two set at 750W.

Space heaters really test the integrity of your household wiring when
running at full blast. The high current can cause arcing in poorly made wire
nut connections and especially in back-stab outlets. In the workshop mine
runs under an aluminum crate to keep it from getting knocked over or
accidentally blocked. So far, so good.

The only issue I would have now if I were you would be whether I felt the
need to remove and inspect the outlet. While they're made of much more
heat-resistant materials, generally, there still may have been heat related
damage to the outlet. Is there a clear point of arcing on the plug blades?
That might tell you where to expect damage to the outlet's mating connector.
If there's substantial pitting on the plug blades, I'd definitely pull the
outlet.

Count your blessings, HR. These sorts of incidents can end up with severe
consequences and their all-to-frequent occurrence is one reason the NEC will
probably require AFCI breakers in all new construction eventually. From
what I read when researching them, arc-fault fires are the last big category
of adverse electrical events that's left to deal with in the code. We've
come a long way from people burning down their houses by sticking pennies in
screw-in fuse boxes.

--
Bobby G.