Why do space heaters catch fire?

[The motor guy]

Do the heaters themselves fail and catch fire or is it just because someone does something to it to catch something on fire?

 

[PimTac]

Flammable materials too close is the major cause. Drapes, furniture, papers etc. If you read all the idiot tags on the space heater it will be explained further.

 

[Wolf359]

In addition to that, the max rating on most portable electric heater is 1500 watts which works out to about 12.5 amps. Most people plug multiple items into a 15 amp outlet so they're pretty much getting the max load out of it without tripping. Over time, if the wiring is a little loose, you get heat build up and an electrical fire. Electrical fires are blamed on space heaters all the time.

 

[VeryNoisyPoet]

I agree that usually is external problems causing the fires. Space heaters have thermal fuses that should cut power if they overheat, and I believe are required by law to have a safety switch underneath that shuts them off if they tip over. But flammable items too close or on top of the heater, or bad house wiring that can't handle the power draw are more likely causes of fire than the heater itself bursting into flames.

 

[pcoxe]

An electric space heater pulls a lot of current and probably does so continuously with little or no off time. This can cause a gradual overheating of every wire, terminal connection, and receptacle in the circuit. It's just a matter of time before something somewhere gets too hot and too close to something combustible.

 

[Snagglefoot]

You can reduce the chances of an accidental fire with a space heater by using an oil filled heater ( their surfaces are not overly hot.) Also you can uses a ceramic heater which also is not overly hot. The worst ones are those wire type heaters that glow red. They are bad news in my opinion. SF

 

[Linctex]

Originally Posted By: pcoxe

An electric space heater pulls a lot of current and probably does so continuously with little or no off time. This can cause a gradual overheating of every wire, terminal connection, and receptacle in the circuit. It's just a matter of time before something somewhere gets too hot and too close to something combustible.

^^^^ THIS is the REAL reason. Two 750 watt heaters in the same room on different circuits is 1000% safer than one 1500 watt heater running on one circuit.

Originally Posted By: Snagglefoot

You can reduce the chances of an accidental fire with a space heater by using an oil filled heater....The worst ones are those wire type heaters that glow red.

The heater type itself is really not important.

 

[PimTac]

Originally Posted By: Linctex

Originally Posted By: pcoxe

An electric space heater pulls a lot of current and probably does so continuously with little or no off time. This can cause a gradual overheating of every wire, terminal connection, and receptacle in the circuit. It's just a matter of time before something somewhere gets too hot and too close to something combustible.

^^^^ THIS is the REAL reason. Two 750 watt heaters in the same room on different circuits is 1000% safer than one 1500 watt heater running on one circuit.

Originally Posted By: Snagglefoot

You can reduce the chances of an accidental fire with a space heater by using an oil filled heater....The worst ones are those wire type heaters that glow red.

The heater type itself is really not important.

I hope your breaker opened with that. That is really bad.

 

[VeryNoisyPoet]

Originally Posted By: PimTac

I hope your breaker opened with that. That is really bad.

Faults like that often will NOT trip the breaker. A high resistance bad connection will happily start a fire even when the total current is well within the ratings of the rest of the circuit. Important to replace worn outlets that get hot to the touch or that do not hold plugs tightly.

 

[Shannow]

 

[Warstud]

Originally Posted By: Linctex

Originally Posted By: pcoxe

An electric space heater pulls a lot of current and probably does so continuously with little or no off time. This can cause a gradual overheating of every wire, terminal connection, and receptacle in the circuit. It's just a matter of time before something somewhere gets too hot and too close to something combustible.

^^^^ THIS is the REAL reason. Two 750 watt heaters in the same room on different circuits is 1000% safer than one 1500 watt heater running on one circuit.

Originally Posted By: Snagglefoot

You can reduce the chances of an accidental fire with a space heater by using an oil filled heater....The worst ones are those wire type heaters that glow red.

The heater type itself is really not important.

Linctex...My mother has a oil heater similiar to that one that has done that exact thing on 2 different outlets. Do I need to replace the outlets. How about the heater plug....it's a little charred...you think it might be ok?

 

[OneEyeJack]

I have a space heater that I set on a tile surface. I plug it into an uprated socket. If it falls over its supposed to turn off but if it does not I'm hoping that on the tile surface it won't do any damage. I run it on a timer and there's a smoke/fire alarm nearby. As you might guess I'm afraid of fire and only use it when I'm right there. I used it when I was really sick with cancer and got the chills. The heat was lovely. Now I don't use it much. It's a heavy duty unit and not one of those cheap ones you get at the department store. So far, so good.

 

[Wolf359]

Originally Posted By: VeryNoisyPoet

Originally Posted By: PimTac

I hope your breaker opened with that. That is really bad.

Faults like that often will NOT trip the breaker. A high resistance bad connection will happily start a fire even when the total current is well within the ratings of the rest of the circuit. Important to replace worn outlets that get hot to the touch or that do not hold plugs tightly.

You could try an arc fault breaker. That might detect it and trip the breaker. Those are now required by code in newer construction in bedrooms.

 

[Linctex]

Originally Posted By: VeryNoisyPoet

Faults like that often will NOT trip the breaker. A high resistance bad connection will happily start a fire even when the total current is well within the ratings of the rest of the circuit. Important to replace worn outlets that get hot to the touch or that do not hold plugs tightly.

EXACTLY!

 

[Linctex]

Originally Posted By: Warstud

Linctex...My mother has a oil heater similiar to that one that has done that exact thing on 2 different outlets. Do I need to replace the outlets. How about the heater plug....it's a little charred...you think it might be ok?

YES, Replace the outlets AND also THE HEATERS with bad plugs. Do NOT take the chance with plugs that are "a little charred" - you don't know how deep the damage is the roll of the dice isn't worth the risk

 

[BJD78]

We have 2 of those oil type heaters as well, not Honeywell,but De Longhi, but these have 2 switches on them and both switches on will be 1500 watts, we have found that just turning on one switch and using 750 watts to be more than ample. At 1500 watts the outlet and plug tend to be a bit warm, probably OK,but why risk it.

 

[bbhero]

And I wondered why my step father ran 12 gauge wire to every single outlet and light in the entire house... Everything regular circuit had a 15 amp/1900+ watt circuit rating going to it. From the homerun to the lights or outlet was 12 gauge. Outlet to outlet on the same circuit was 12 gauge. Every connection inspected very closely to make sure it was right. Zero 14 gauge wire anywhere in that house. He ran 10 gauge to the refrigerator, the dishwasher, dryer and washing machine. Over kill for sure. But safer. Everything was way above the NEC.

 

[Donald]

Originally Posted By: bbhero

And I wondered why my step father ran 12 gauge wire to every single outlet and light in the entire house... Zero 14 gauge wire anywhere in that house. He ran 10 gauge to the refrigerator, the dishwasher, dryer and washing machine. All of the homeruns were 12 gauge for all the rooms they went to. Over kill for sure. But safer. Everything was way above the NEC.

If I were building a house every circuit that was not dedicated lighting would be run using 12 gauge wire. The extra cost would be minimal, like under $100. You can still have them as 15 amp circuits in bedrooms.

 

[Virtus_Probi]

Originally Posted By: Linctex

Originally Posted By: Warstud

Linctex...My mother has a oil heater similiar to that one that has done that exact thing on 2 different outlets. Do I need to replace the outlets. How about the heater plug....it's a little charred...you think it might be ok?

YES, Replace the outlets AND also THE HEATERS with bad plugs. Do NOT take the chance with plugs that are "a little charred" - you don't know how deep the damage is the roll of the dice isn't worth the risk

Ditto, Linc, Ditto! Don't use those charred outlets for anything before they are replaced.

 

[bullwinkle]

Originally Posted By: bbhero

And I wondered why my step father ran 12 gauge wire to every single outlet and light in the entire house... Everything regular circuit had a 15 amp/1900+ watt circuit rating going to it. From the homerun to the lights or outlet was 12 gauge. Outlet to outlet on the same circuit was 12 gauge. Every connection inspected very closely to make sure it was right. Zero 14 gauge wire anywhere in that house. He ran 10 gauge to the refrigerator, the dishwasher, dryer and washing machine. Over kill for sure. But safer. Everything was way above the NEC.

That's a smart move, but it seems that the cheap, junky, receptacles are the main issue. Add a heavy load, and it's like a minature arc welder buzzing away in the wall-until the studs get hot enough to catch on fire...