Extension Plug Fire Hazard?

[Otakat]

My fiancée had a go at me this morning for not unplugging my mains extension lead with my computer, monitor and my powerline in. She said it was a fire hazard and could potentially kill us all overnight if it set on fire. As the laziest person that has ever lived, I must ask; is it actually a danger? I don't understand how it's different to living a fridge or a freezer plugged in overnight. Finally, if it is a hazard, would getting one of those surge protected extension sate her paranoia? (I'll add that we rarely get thunderstorms here, just in case that's a factor).
Cheers!

 

[gangrel]

At work, our safety people said No to a power strip connected to another power strip, and similar configurations (including UPSs in there)...because of the risk of an overload. This is, I think, especially true with extension cords and power strips; they're not constructed for big loads. But it's the load that's the issue; it's not going to spontaneously melt down in the middle of the night when there's no appreciable load.

 

[Saberus]

She's being overly paranoid. Daisy-chaining extensions is a no-no in the the US workplace because of trip hazard and potential to overload a circuit (It's an OSHA thing, and it makes sense). Leaving stuff plugged in that even at full tilt is below the current limit for the circuit is no danger, as long you're not using cheapo made in China extension cords that have barely any copper in them. Basically if the wires aren't getting hot, there's no fire hazard.

 

[Otakat]

But it's the load that's the issue; it's not going to spontaneously melt down in the middle of the night when there's no appreciable load.

Basically if the wires aren't getting hot, there's no fire hazard.

Thanks for the replies, and apologies for my ignorance on the subject but I recall her mentioning something about something that can happen to the lines that ends up overloading plug sockets and making them catch fire. Is what she talking about a power surge? Also, do you have any links with proof I can show to her? I'd like to barrage her with evidence, because apparently the next time I leave a plug in I'm sleeping on the couch :lol:

 

[Saberus]

Again, if it's not using cheapo dollarstore extension cables and not trying to run everything in the home off one outlet, you should be fine.

A single powerstrip that is rated for your workload and isn't exceeding the outlet's limits is fine.

This is fine:

This is... ok:

This is bad:

This is really bad:

This... just.... never:

Safety tips from State Farm:

 

[gangrel]

A power surge...even a lightning strike...isn't going to cause melted plugs. It *can* toast the the equipment...but that's why surge suppresion exists. And this won't happen if the equipment's not turned on.

As Saberus notes, the big issue is using skinny, teeny-tiny cables with excessive loads. I used to have a torchiere halogen floor lamp; it had a 500W bulb in it. At full brightness, it was a space heater! The bulbs were banned, tho, because running 500W through standard lamp cord IS excessive, and did pose a fire risk. But, look at lamp cord, versus the typical power cord on a PC, and then the power cord on even a power strip.

 

[ssddx]

unless you're running high amp draw equipment over the extension cord its not going to be any more fire hazard than just plugging the equipment in would be. (pc hardware is not high amp draw).

multi-outlet plugs can be a fire hazard if you draw too many amps over them similar to above. since you likely are only running pc equipment on them its not really an issue.

now you really SHOULD have a surge protector even if you do not get storms as it will help protect you equipment (if you have fuses or breakers in your house this should really trip first but a surge protector is still a good idea).

generally though i think she is being paranoid. unless you're using a small gage wire with heavy load you should be fine. having xmas lights in a xmas tree is far more of a fire hazard.

 

[westom]

> Finally, if it is a hazard, would getting one of those surge protected extension sate her
> paranoia? (I'll add that we rarely get thunderstorms here, just in case that's a factor).

First a power strip must be UL listed. That means it will have a 15 amp circuit breaker. Shape of each plug says that receptacle must power up to 15 amps. If it cannot, then it will not have a UL Listing.

Second, greater source of fires is power strips WITH surge protector parts. Early 1980s PC Magazine articles noted this common problem. UL has since upgraded their ratings three times because protector strips still cause fires.

Anyone can read these numbers. Potentially destructive surges can be hundreds of thousands of joules. How many joules does a protector strip claim to absorb? Hundreds? Thousands? A thermal fuse must disconnect protector parts as fast as possible during a surge - and leave that surge still connected to attached appliances. Unfortunately, sometimes that emergency backup protection device (thermal fuse) does not trip fast enough. Even fire marshalls reported fires in their fire houses when that thermal fuse did not trip fast enough.

Meanwhile, Schneider Electric recently purchased APC. Then announced some APC products are so dangerous as to be removed immediately. Because a thermal fuse does not disconnect near zero protector parts fast enough.

Yes, be concerned. Or even better, properly earth a 'whole house' protector so that even a power strip protector or UPS is protected.

Again, numbers. A destructive lightning strike may be 20,000 amps. So a minimal 'whole house' protector is 50,000 amps. Because no protector must fail due to a surge. So that even direct lightning strikes do not damage this superior solution - that costs about $1 per protected appliance.

 

[Saberus]

1) Whole home protectors that can handle the amperage you recommend cost much more than $1 an appliance.
2) The manufacturers do not claim they protect against lightning.


If he's using less than the rated amperage of the outlet in the wall, there is no way a strip using proper gauge wires will overload and catch fire. Anything more than 15A on the wall outlet will trip the breaker for the wall outlet. This isn't talking about surge, this is normal draw.

Cheap strips are the real danger in this case: wires are too thin and often there is improper isolation of the wires. Both of these can lead to fire hazards. And worse, the cheap strips often put fake UL listings.

Use power strips from reputable manufacturers that use proper gauge wiring, don't daisy chain strips, and don't overload the circuit.

 

[westom]

1) Whole home protectors that can handle the amperage you recommend cost much more than $1 an appliance.
2) The manufacturers do not claim they protect against lightning..

No, a 'whole house' protector is not 100% protection. Because, first, it is only as effective as something completely different that does all protection - single point earth ground. And because standards define protection at only 99.5% to 99.9%. It is not 100%. And it is the only solution to surges such as lightning, as found in every facility that cannot have damage including commercial broadcast stations, all telco COs, pump stations, and nuclear hardened communication facilities. The telco CO suffers about 100 surges with each storm. Why does your town still have phone service for four days after each storm? Because the only proven protection from surges - a 'whole house' solution - has been routine protection for longer than any of us have even existed.

So as to not make damage easier, they will often ban plug-in protectors.

Any other protection method (especially power strips that may otherwise cause a house fire) also needs to be protected using a solution that costs about $1 per protected appliance. It costs more if you only have ten appliances - have no GFCIs, no clocks, no radios, no dishwasher, no washing machine, no door bell, no power strips, no furnace, no smoke detectors, etc. All must be protected. Only possible with a 'whole house' solution. A 50,000 amp protector even sells for that little in Lowes and Home Depot..

 

[Saberus]

And it is the only solution to surges such as lightning, as found in every facility that cannot have damage including commercial broadcast stations, all telco COs, pump stations, and nuclear hardened communication facilities. The telco CO suffers about 100 surges with each storm. Why does your town still have phone service for four days after each storm? Because the only proven protection from surges - a 'whole house' solution - has been routine protection for longer than any of us have even existed.

This is disingenuous and a lie of omission. Those facilities have layers of power conditioning, load balancing, UPS and power distribution. Each layer has it's own redundancy. The computers are so thoroughly isolated that one can be on the computer floor and never know that there was an issue on one power feed unless you were close enough to one of the power distribution units to hear it switch over or beep an alarm. Even losing all mains power and going to UPS then generators, the lights don't even flicker. To imply that the only protection is a single device or even a single type of device is deceptive. It is further deceptive to imply that a homeowner can get the same grade of protection on the cheap by slapping a device into their breaker panel. Especially when the makers of these devices claim less protection than you are.

So as to not make damage easier, they will often ban plug-in protectors.

I have been in telco CO facilities, commercial radio stations, and NAP data centers. This is bold-faced lie.

Any other protection method (especially power strips that may otherwise cause a house fire) also needs to be protected using a solution that costs about $1 per protected appliance. It costs more if you only have ten appliances - have no GFCIs, no clocks, no radios, no dishwasher, no washing machine, no door bell, no power strips, no furnace, no smoke detectors, etc. All must be protected. Only possible with a 'whole house' solution. A 50,000 amp protector even sells for that little in Lowes and Home Depot..

Calling a GFCI an appliance is a stretch at best.

 

[westom]

This is disingenuous and a lie of omission. Those facilities have layers of power conditioning, load balancing, UPS and power distribution. ....
Calling a GFCI an appliance is a stretch at best.

GFCI is just another computerized appliance in a house. It also also must be protected. Protection required for the same reason a TV requires protection. These electrical concepts are completely new to you. Your replies are contradicted by numbers you should have learned in engineering school - had you attended.

All incoming wires to every CO go underground BEFORE approaching the building. Large underground vaults contain a 'whole house' protector for every wire inside every cable. Surges are connected to earth in these underground vaults before even entering the main building. Obviously you did not know this.

Separation between protector and electronics increases protection. Again, numbers are provided. Telcos want their protectors are up to 50 meters distant from electronics. Protection increases with every foot shorter to earth. Protection increases with every foot longer between protector and electronics. Only one of us did this stuff - as demonstrated by facts with numbers. It was not you.

Why are Ufer grounds important? Reinforced concrete is an excellent earth ground. Originally pioneered by Dr Ufer so that direct lightning strikes to munitions dumps did not cause explosions. If you knew anything about COs, then you also knew about Ufer grounds. And why these grounds are critical to protecting COs. But again, only one of us actually did this stuff. And learned why ... with numbers.

What has no earth ground? Plug-in protectors and UPS. These devices are only for a completely different transient (also called a surge) that is usually made irrelevant by protection already inside every appliance (including GFCIs).