would electric heater melt the insulator?

[cpteoh26]

kettle cable melt

hi.
as i know, the electric kettle, electric water heater and iron are all use resistor thermal to get thing heat up.
since our wires are made from copper, not only a great electric conductor, but also a heat conductor, is it correct to assume the wires will get heat up also when the heater is on?
isn't the temperature of 100C would melt down the insulator around the wires?

Added after 2 minutes:

assume the thermostat fuse is not in use/not longer functioning..

is my theory correct?
water heater, iron, kettle use resistance thermal to get thing heat up, but it heat up the wires also..

what i mean is, the heater get heat up by thermal resistance theory.
which mean, the copper wire will connect to the heating element.. then current flow thought the heating element (thermal resistance), it get heat up...
but the copper wire is psysically connected to the heating element, which mean the heat will spread to the copper wire (copper a good thermal conductor) as well..

therefore, copper wire will get heat up as well??

 

[cameo_2007]

nsulator heater

basic understanding for this is,

the heating element and the copper wire are not made up of the same material.And the copper wire will not get heated just as the same as heating element.

There are certain theories on how heat is produced,depending upon the material,cross section of teh material etc(which i dont know)

so generally speaking what you assume is not correct.

 

[FvM]

copper melter electric

An electrical cable (wire) has a specified current capacity, as long as it isn't considerably exceeded, it will never get overheated or even have the isolation melt down. This is true for regular operation only, if you e.g. roll up a long cable to a small coil, it may get damaged at heavy load.

 

[cpteoh26]

what i mean is, the heater get heat up by thermal resistance theory.
which mean, the copper wire will connect to the heating element.. then current flow thought the heating element (thermal resistance), it get heat up...
but the copper wire is psysically connected to the heating element, which mean the heat will spread to the copper wire (copper a good thermal conductor) as well..

therefore, copper wire will get heat up as well??

 

[FvM]

therefore, copper wire will get heat up as well

The copper wire conducts only a small amount of thermal power in length direction. You can calculate it in detail for a particular geometry. Basically, the heat is dissipated from the wire by thermal conduction through the insulation and convection into the air. At high temperatures, also thermal radiation plays a part. You can do a test by dipping a copper wire of some length (e. g. 12"/30 cm) into boiling water and trace the temperature along the wire. For a home appliance conductor wire (AWG16/1.6 sq.mm), you should be able to keep the other end in your hand.

Inside a heater, that involves high temperatures, you'll usually find some additional measures to reduce thermal conduction along the first wire section.

As another interesting experiment (I once did unintentionally): If you place a heater in a vacuum chamber, the conducted heat can melt the cable insulation at a considerable distance.

 

[cpteoh26]

well, i get to this question because i had an accident last week, the 3-pin plug of a kettle burnt my finger.

i boil water with my 1.2L kettle as usual, after boiling the water, i take out the 3-pin plug from the wall socket, unfortunately, the metal plat at the 3-pin plug was very hot and it burnt my finger.

it soon come to my interest to know, how this heater actually work, and how the heat is isolated from the heating devices to the copper wire.

**broken link removed**

 

[sreevyas]

The heater is different material it is not copper, Heter is normally nichrome or other high resistive material and due to Joule heating (I2R)effect it produces the thermal energy.
If drws more current or any abrupt pulse that time copper electrical wire reaches more than 120 deg C then insulation will burn. Does it make any sense!?

__sree

 

[cpteoh26]

The heater is different material it is not copper, Heter is normally nichrome or other high resistive material and due to Joule heating (I2R)effect it produces the thermal energy.
If drws more current or any abrupt pulse that time copper electrical wire reaches more than 120 deg C then insulation will burn. Does it make any sense!?

__sree

i mean, the current will flow from the copper wire to the high resistive material (to heat up and boil the water). this mean, they are physically connected.

copper is a good heat conductor also, which mean the heat will spread to the copper wire also??

assuming the heater run for 1 hour, for cooking.. then it might melt down the insulator for the copper wire..

 

[Angel_s]

The voltage also plays a role and moreover the melting point of copper needs to be considered..

 

[cpteoh26]

i mean the insulation around the copper..
not the copper melt down..
the rubber(insulation around the copper) will melt a lot easier than the copper

 

[FvM]

The hot connector is obviously caused by a loose screw connection inside the socket or the plug, or less likely by a worn out socket contact. That's a common problem. As you can see from the photo, the connector has 13 A specification, it is allowed to get warm but not really hot in regular operation.

Regarding the heat conduction along a wire question, I'm under the impression, that you prefer general considerations rather than analyzing the problem in it's real parameters. I suggested an example setup, you may either believe my prediction, try it yourself, or continue speculative discussions.

You may also ask, if your assumption would be true, why it isn't happening with any electrical heater arround the world?