Can the resident people with knowledge of electrical matters please help me explain this hazard to someone? This person does not understand why it isn’t safe to leave an extension cord plugged into the wall, but attached to nothing. They don’t see it as any more dangerous than leaving the house’s circuit breakers on. I was taught that it was unsafe, but when I tried to explain why, I could not find a way to phrase it so they could understand it. I need the science facts and cites proving why it is unsafe if you know of any. They aren’t stupid, but they are stubborn and they weren’t taught that safety measure growing up, so they are finding it hard to believe now. I think if shown the scientific reasoning, they will be more able to grasp it.
Everything man makes breaks. If you have a cord plugged into a wall, if somebody steps on it, there is a wildly small chance that it will break, short, and cause a fire or loss of power (due to blowing circuit breakers). If there is no power cord plugged into the wall, this can’t heppen (beyond things you can control, that is; if the wiring in the walls is going to short out, there isn’t much you can do about it).
However, if the people who want to leave power cords plugged into the wall are generally careful around them and don’t step on them, then there isn’t much harm that I can see, and the very small risk should balance out the long-term advantage of always having an extension cord ready to go.
The key to using flexible cords is remembering that they are not a substitute for installed wiring in a dwelling, hence their prohibition as such by the NEC. Installed wiring is of larger gauge, and is also physically protected by the dwelling structure. Some extension cords are imported by persons who use counterfeit UL product labeling, creating yet another type of hazard. Unfortunately, we have a difficult time altering human nature, hence the Arc-Fault-Circuit-Interrupter.
If there is nothing plugged into the extension cord, there is no current flowing, so electrically this is not any more unsafe than an unused electrical outlet in the wall.
However, there are other hazards to consider.
[ul]
[li]Someone may trip over the cord if it is left lying on the floor.[/li][li]Someone may see the cord and fashion a noose to hang themselves.[/li][li]Hi, Opal[/li][li]Someone may stick metal objects into the holes and shock themselves.[/li][li]Someone may run over the cord with a vacuum cleaner and cause damage to the vacuum.[/li][/ul]
Seriously, the much greater danger associated with these cords is plugging something into them which draws more current than the cord is rated for, which causes a serious fire hazard.
One thing that small children do almost automatically is pick up things from the floor and put them in their mouths. It that thing is the business end of an extension court it’s reaaaaallllly bad.
[QUOTE=FatBaldGuy]
[ul]
[li]Someone may run over the cord with a vacuum cleaner and cause damage to the vacuum.[/ul] [/li][/QUOTE]
Or, alternatively, someone may run over the cord with a vacuum cleaner, the cord may get damaged by the rotating beater bar and short against the vacuum or itself, possibly electrocuting the vacuumer.
You might also warn them about the fire hazard associated with laying a throw rug over the cord. The backing on carpet is very abrasive; walking on the throw rug may eventually abraid the insulation on the wire. This happened in my own home and I’m an electrician and should know better. :smack: Luckily, nobody was hurt, but we had about $3,000 in smoke damage.
My mother received a nasty shock and burn when the extension cord she had draped over a metal utensil rack to plug her iron into shorted out against the utensil rack. She grabbed a spatula and it grabbed her right back.
I would not consider it “unsafe” to leave an extension cord plugged in. But as others have pointed out, there are some risks in doing so. To avoid these risks, extension cords should be unplugged after use.
Well I remember when my dad took down the unattached garage next to our family house and left the bare electrical wire sticking up out of the ground (in case he was going to build another one in the next twenty years!) and the city telling him to disconnect it. Damn unsafe. Two wires sticking up with current capable of being drawn. No current is drawn until somebody makes the circuit! Same with an extension cord. Don’t do it.
I guess I’d be interested in hearing your reasoning as to why it’s unsafe. There’s nothing inherently dangerous about it except, as people have noted, that it represents a slightly greater chance of shock or fire if physically damaged. However, you might consider that the humble power strip is used in millions of offices and homes and is nothing more than an extension cord with all the unused outlets being equivalent to your extension cord with nothing attached.
See above. All you need to activate the circuit is to either A) attach a load to the wires or B) cross the wires. That is why the “ALL” local codes in the United States make it illegal (because they follow the NEC [National Electric Code] ) to allow extension cords to be used in permanent structures.
And to cite some examples. I have seen local bars brunt down because they allowed “extension” cords to be permanitly set up for the local bands. They end up drenched in water/filth/whatever and make a circuit that feeds a source after the owners have gone home. Electrical outlets are supposed to be a cetain number of inches from the ground, provide a path to ground, be in conduit, ect,ect , ect. That is what the NEC is about, trying to prevent people from doing studip thing with electricity. Not trying to rant, but electricity is to be repected.
That’s why I prefer the kind of power strips that have the “child safety” covers to go in each outlet that isn’t being used.
When I was 12 I had the business end of an extension cord fall apart in my hand, exposing the live leads. Granted, that’s not much of a problem now that the plugs are molded, but once you find yourself completing a 120V household circuit, you never look at an extension cord the same way.
Well, but it still doesn’t answer the question why you think it’s inherently dangerous. The OP didn’t make it sound like you were worried about physical abrasion of the cord causing problems. It made it sound like you were worried that there was actual current flowing through the open socket. I may be reading more into the OP than was there, but I’m genuinely curious as to what your original reasoning was.
As I said, almost every office and home office in the country uses power strips without any significant epidemic of, well, anything as far as I can tell.
OSHA has something to say about it. The page is about household dangers. On the job site you generally have to have a GFCI (ground fault circuuit interrupters) - which you are not likely to see at the other end of the extension cord.
Here’s the word from 2005 NEC, Article 400 Flexible Cords and Cables:
400.8 Uses Not Permitted. Unless specifically permitted in 400.7, flexible cords and cables shall not be used for the following:
(1) As a substitute for the fixed wiring of a structure
(2) Where run through holes in walls, structural ceilings, suspended ceilings, dropped ceilings, or floors
(3) Where run through doorways, windows, or similar openings
(4) Where attached to building surfaces
(5) Where concealed by walls, floors, or ceilings or located above suspended or dropped ceilings
(6) Where installed in raceways, except as otherwise permitted by this Code
(7) Where subject to physical damage
Using an outlet strip for your PC isn’t of concern, so long as the device is in good repair. Yes, it’s arguable that the outlet strip violates 400.8 (1), however I look at the use, and if the device is being applied in a manner consistent with it’s intended use and design ampacity, I don’t get worried. When I see those same outlet strips feeding a tangle of cords that supply the TV, VCR, fish tank heater, and window AC unit, it’s time to wave the red violation flag.
Ditto for extension cords-they are for temporary use. Run the electric drill while you’re up on a ladder, power the electric hedge clippers, and so forth are acceptable uses. When you’re done with the task, the cord is disconnected and put away. When a cord is running around the baseboard of the living or bedroom and has been there since the last election, it’s time to replace it with installed wiring.
Spot on. Good work.
(As if you needed assurance.) 