OK, I know just enough about electricity to be dangerous, but this one
has me stumped.
Today I had an oil convection electric heater (1500W) turned on in the
bathroom to heat up the room before taking a shower, and when I
unplugged it, I noticed the prongs of the plug were HOT. Probably like
175°F hot...almost too hot to touch. Then I put my hand on the socket
and that was hot, too.
Yet the cord to the heater wasn't even warm.
If the heater uses 1500W I assume that at 125V my load is about 12A...right?
It's an old house but the wiring is modern Romex.
Why would the prongs of the plug and the socket get so hot? Resistance
in the plug? (The plug APPEARS undamaged, and we always pull it out by
grabbing the plug, not the wire).
Should I put a new plug onto the cord?
Is it likely there was resistance or a bad connection in the socket?
Thanks for any clues.
Anytime I have installed an electrical outlet I make the connections by
screwing them down snugly. I have found that contractors tend to take
the fast way out which is to strip the wires and shove thm into the
back side of the outlet which may be fine 95$ of the time but when you
are drawing high amperage its better to have them screwed down.
There has to be more than normal resistance in the plug and/or the
outlet. I'd examine the plug for any problems. Then I'd try plugging
it in another outlet. If it works there without getting hot, I'd
investigate the outlet. Could possibly be corrosion, especially since
it's in the bathroom, or a loose connection at the outlet.
This is good advise. How tight does the outlet feel when plugging
Also if the blades on the heater cord are the "folded" metal type as opposed
to solid you might try spreading them a bit for better contact.
As noted, the wires to the outlet (in the wall) may not be making good
connections with the outlet (don't use a push in connector, use only the
screw down type. It is also possible that the plug is not making good
contact with the outlet. For both of these I suggest replacing the outlet
with a commercial grade outlet (cost maybe $2.00 more than the cheap
residential grade that is likely there now).
It is also possible that it is just normal. However I would replace the
outlet, in fact I have replace all my outlets that have heavy loads on them.
I would question about putting a new plug on the wire. Is the current
one molded on? The replacement may not be a good as the original. On the
other hand replacing the entire cord with a new high quality cord is a
On any 1500 Watt heater I've ever owned, the plug and outlet always got warm
when run continuously on the 1500 Watt setting. At one location, it was a
new oil filled heater in a new house and all the outlets I tried had the
same result. I never trusted those things above the 900 Watt setting.
I worked on film and TV crews for many years. We used many 1000W and
2000W lights that we'd bring into a location and plug in existing
outlets. You never know the shape of the outlet you're plugging into.
Even the 1Ks would often get hot at the plug end and once that happened
it was just a matter of time. We bought new plugs by the case lot
because they often needed replacement.
Once an outlet has gotten overheated like this, it's a good idea to replace
it, regardless of the precise cause because it is now probably heat damaged.
Replacing it will probably solve the problem. Use a "spec-grade" outlet.
They'll cost $2-$3. Use the screw terminals.
Once it's replaced, check the temperature again. If it's still getting
that hot, then you consider replacing the cord or plug on the heater, and
make sure you get a good quality plug.
If the outlet was installed using the "push in" terminals, take some
time and check any previous outlets in the circuit for overheating too.
[Plugged an A/C into a circuit and as a result, _three_ push-in terminal
outlets burned out... It was Aluminum wire (it was never legal to use
push-in terminals for Al), but, I don't trust push-in even on copper.]
Chris Lewis, Una confibula non set est
It\'s not just anyone who gets a Starship Cruiser class named after them.
With power to the receptacle off: Plug it in and unplug it
several times, say 8 or 10, or better yet, scuff up the plug
prongs too with some fine sandpaper. If the heat becomes less,
it's just corrosion on the plug pins and/or inside the
If it plugs/unplugs more easily than normal (compare to other
outlets) or is real sloppy, the receptacle is worn out or bent
out of shape inside.
If the plug is a molded type, it's possible there are broken
wires (from plugging/unplugging in the past) right at the heat
relief area. See if that particular area is hottest. If so, you
need a new plug.
THEN if still no joy, go after the wire connections inside.
Usually a hot plug is a sign of poor contact. If the plug heats,
so will the receptacle due to the metal to metal contact.
: OK, I know just enough about electricity to be dangerous, but
: has me stumped.
: Today I had an oil convection electric heater (1500W) turned on
: bathroom to heat up the room before taking a shower, and when I
: unplugged it, I noticed the prongs of the plug were HOT.
: 175°F hot...almost too hot to touch. Then I put my hand on the
: and that was hot, too.
: Yet the cord to the heater wasn't even warm.
: If the heater uses 1500W I assume that at 125V my load is about
: It's an old house but the wiring is modern Romex.
: Why would the prongs of the plug and the socket get so hot?
: in the plug? (The plug APPEARS undamaged, and we always pull it
: grabbing the plug, not the wire).
: Should I put a new plug onto the cord?
: Is it likely there was resistance or a bad connection in the
: Thanks for any clues.
Following up on another poster, first determine if the problem lies with the
plug or the socket. Power the heater from another socket far away. If the
plug still gets hot, you've got a plug problem; if not, you've got a socket
(It IS possible, too, that you've got BOTH a plug problem AND a socket
If while you are messing with the receptacle you notice that you have 14
gauge wire back there, discontinue using that circuit for the heater. For
1500W you need a full 20A branch with a 12 gauge wire.
I would also add that most receptacles are actually 15A devices (see
markings molded into plastic). Just get a 20A receptacle and replace and
you should be fine if you follow all the other advice given here.
IME, such plug/outlet heating is normal when the appliance draws near
the rated current of the circuit for "long" periods of time. Plug-in
electrical heaters are a standard culprit.
In one work situation, local Fire Marshal would go ballistic on finding
any plug-in electric heaters. The sort of unit many secretaries MUST
have. Mainly because of the insidious way they fail. Day after day,
they work fine. Then POOF!
Of course, mfg. cost-cutting doesn't help, either with plugs or cables
or outlets or connectors. For any sustained heavy load, you want the
best available, even if it costs $.50 more.
None of this matters. The prongs are hot because there is a bad
connection between the prongs and the receptacle slots., or possibly
between the wires in the walls and the receptacle.** If they're not
loose, put in a new receptacle.
In 1980, I lived ina building in Brooklyn built in 1930. The heat was
broken iirc and I was using a heater in my little bedroom ( I had 6
rooms but slept in what was intended to be the maids room.
Something woke me in the morning, and I looked at the foot of the bed
and a foot to the right to see 1 or 2 inch flames coming from the
plug! I didn't know what to do, but my reflex was to unplug it.
Each time I reached for the cord, the girl next to me would pull my
arm back. I guess she was scared. I reached again, and she pulled my
arm back again. At least three times before I overpowered her.
It was like a comedy movie. I think she yelled a little too, in fear.
I'm glad I was stronger than she was.
The fire went out as soon as I pulled the plug from the wall. it was
either hard rubber or bakelite that was burning. There was nothing
flammable within a foot of the plug, except maybe if pieces fell off
the synthetic carpet could have burnt.
The plug was normal but the receptacle was 50 years old. Actually,
it wasn't even a twin outlet, only one outlet in the center.
(You guys know I don't talk about girls, but this was so on point.)
Another thing one can sometimes do is, with prongs that are folded
back, carefully so you don't cut your self, put a knife in between the
two layers, and spread them apart so they are springy themselves to
make up fo for the receptacle slot parts. But this isn't the
problme in this case, I'm positive.
** in theory between the prongs and the wires they are connected to,
but that couldnt be it. The heat woudn't make it to the part of the
prongs that show.)
Remove NOPSAM to email me. Please let
me know if you have posted also.
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