I told him if he tied knots in his cable ...

[Konrad]

I've been seeing a lot of this beauty:

I told him if he tied knots in his cable the packets wouldn't be able to fit through it!:banana:
Heh.

"The knot trick"

Urban legend claims that tying knots in your AC power cord can provide a small measure of added protection from lightning surges. The idea is that the extremely high voltage/current from a lightning strike will get "shorted" by an inductive loop, almost instantly generating enough heat to melt through the knotted conductors, thus saving whatever equipment is downline from absorbing most of the surge power. Sort of like a fuse, and anyone can do it for free.

It's been a controversial topic, recommended and debated and denounced by numerous "experts" all across the internet for several years now. Most of these people are just ignorant repeaters (All Glory To The HypnoToad! (http://r33b.net/)), but some are indeed highly qualified and seem to know what they're saying; a few have even established local policies or ordnances which recommend or require this practice.

Critics point out that power line and transformer circuits already act like lightning knots, and numerous system-wide lightning arrestors (including the residential service breakers and grounding rods) are already present; any power surge that unstoppably penetrates so deeply into residential circuits won't be deterred substantially (if at all) by an insignificant extra knot. Some complain that burning wires are even a fire hazard, though I personally suspect the fire hazard would be much the same regardless of whether your $6 power cord or $2000 computer started melting.

The most avid proponents carry things to ridiculous extremes, tying lengthy series of knots on the power cord to every appliance they own. A few fanatics even describe internally hardwiring every receptacle in their home with these knots. Many firmly attest that this miraculous panacea "solved" all manner of power problems or "protected" equipment that would have otherwise certainly fried.

I recall once reading some respectable publication (an older edition of Scott Mueller's Upgrading & Repairing PC's, I think) which briefly mentioned the knot theory as an exciting new discovery (and recommended the practice as a small-gain-at-no-cost tweak) ... something about a study by a university ... University of Washington, maybe.

Does anyone else know more?

[Diamon]

Or you could buy an actual fuse or even a surge protector and just put it on the AC cable to your computer 0_o. I bet the success rate of that would be roughly 8300% higher then what you'd get from tying knots on every single cable you own -_-

[BuzzKillington]

Submit it to mythbusters!

Also, I found it odd... A COX tech told me to plug my router and modem directly into the outlet and to NOT use a surge protector. I didn't listen to him but he said they flex a lot and make your connection less consistent. o.0

[farlo]

that may have some slight truth to it, but only if you're using some cheap HK surge protector from ebay that was got for a dollar.

[Trace]

Stealing my signature are we now?

[x88x]

mDust was referring to Cat5/6/etc cables, not power. I would guess as just a way to get somebody to understand that those cables need to not have any kinks/knots/etc without having to painfully explain why.

On topic of the power knots, I could see it maybe working in some cases, but I'm also of the opinion that anything worth doing is worth doing properly, so imo if you are placing yourself in a position where you need to do this, you're doing something wrong. Put proper fuses/surge protectors/etc in place and you don't have to worry about it. That sorta brings me around to a facet of a pet peeve of mine..that is, people paying ridiculous amounts of money on their computer but ignoring peripherals (ie, mouse, keyboard, monitors, or in this case, power systems). To use your example, yes, it is better to fry a $6 power cable than a $2000 computer, but if you spent $2000 on a computer and can't be bothered to pay $50 for a good surge protector and UPS, then I really have no sympathy if your $2000 computer fries. :P


Also, I found it odd... A COX tech told me to plug my router and modem directly into the outlet and to NOT use a surge protector. I didn't listen to him but he said they flex a lot and make your connection less consistent. o.0

...and stuff like this is why I stopped listening to cable company techs a loong time ago. :facepalm:

[Airbozo]

Submit it to mythbusters!

Also, I found it odd... A COX tech told me to plug my router and modem directly into the outlet and to NOT use a surge protector. I didn't listen to him but he said they flex a lot and make your connection less consistent. o.0

When the PSU on my dell died, they insisted I not plug into a surge protector as this was the cause of the problem. I informed the guy he had it backwards and he argued with me. I "reminded" him that I have been working on computers since before he learned to use the toilet and he put his supervisor on the line who told me the exact same thing. I also argued with him and asked that he provide me with proof of this absurdity or to stop misinforming customers. He had no proof and I escalated the issue to a sr. engineer who eventually refuted the idea and told the support team to stop telling people wrong information.

I got my PSU fed-ex the next morning, installed it and plugged it back into my power strip.

Oh and it really is cheap insurance. I had just finished building my F-I-L a new computer when a lightning strike hit their house. His old line protector smoked and the psu in his computer died. Since the power strip came from APC (I think it was apc), they paid for the PSU replacement!

[Oneslowz28]

I run $40 APC surge protectors on all my major appliances except for kitchen stuff. When I bought my first big screen tv back in 2004 (JVC HDILA 51" rear projection) the manual said to not plug it into a surge protector because of the current it drew.

And now I am going to add a bit of controversy here. Lightening jumps through a mile of air, Air is a good insulator. So if lightening can jump through a mile of insulator, then why do you think a .5" gap in a fuse will stop it?

[mDust]

Stealing my signature are we now?

I believe your signature belongs to me at the moment...;)


I would guess as just a way to get somebody to understand that those cables need to not have any kinks/knots/etc without having to painfully explain why.Indeed.


I would think that if the wiring in your home takes the brunt of the discharge, no knots, fuses or surge protectors are going to stop that voltage. A typical lightning stroke has a peak power output of 1 terawatt...divide that by a typical 30,000 amps and we get (very) roughly 33 million volts. That's more than enough to arc through the air and continue through your electronics on its merry way to the ground.

[Disclaimer: I got this info from wikipedia (http://en.wikipedia.org/wiki/Lightning)and if I end up looking like a doofus, it's their fault not mine.]

[x88x]

II would think that if the wiring in your home takes the brunt of the discharge, no knots, fuses or surge protectors are going to stop that voltage. A typical lightning stroke has a peak power output of 1 terawatt...divide that by a typical 30,000 amps and we get (very) roughly 33 million volts. That's more than enough to arc through the air and continue through your electronics on its merry way to the ground.

On the other hand, if your electrical system is built properly and it takes a lightning hit, the current should never hit you electronics in the first place. That's why we have grounding rods.

[mDust]

That's why we have grounding rods.

...or do we?:think:

[x88x]

...or do we?:think:

:eek: I certainly hope we do. :eek:

...along that note, when my sister bought her house she found the grounding line sitting on the ground about 6" away from the rod...everything was run and the line was plenty long enough, the previous owner just didn't have it connected. :eek:

[Konrad]

Stealing my signature are we now?
I believe your signature belongs to me at the moment...;)
Hey, I'm a noob. I need gimmicks to make people listen. ;)

Of course tying knots in your ethernet isn't going to accomplish anything. A secondary lightning surge carried through phone or cable lines might be enough to fry your modem, it used to happen all the time in past decades when electronics sucked. I doubt it's more than a Reset issue today. Anyhow, this is described as more of an "EMP" sort of effect, a huge voltage spike with insignificant current; good enough to use air as a conductor but insufficient for melting wires.

The reason the knots might (theoretically) be useful on AC lines is because the surge power is easily capable of melting mere 14 gauge wiring (and insulation) in a flash. Yes, it might be enough raw power to conduct through air so a fuse would technically be useless, but can it hurt to attempt to remove the appliance from the circuit? It's not like Zeus is deliberately hurling bolts of punishment at your computer (though it may seem that way). It's just as likely to hit anything else, maybe even hit you or your trashcans instead.

I doubt the knots can do much at best. Maybe give your computer another 1-in-1000 chance in a storm. Maybe. And it's NOT a substitute for any kind of decent power/surge protection system ... still, tying a little knot costs nothing.

I personally prefer a trusty low-tech massive 1500W Hammond isolation transformer with respectable thyrite resistors (screw those feeble surge bars with their wimpy MOVs, they're all semi-disposable anyways).

An interesting problem is that many skyscraper businesses design elaborate lightning protection from top to bottom. Then they place all their servers at the bottom, in the best grounded room. Isn't that the first place lightning is going to travel if when strikes the building?

[x88x]

An interesting problem is that many skyscraper businesses design elaborate lightning protection from top to bottom. Then they place all their servers at the bottom, in the best grounded room. Isn't that the first place lightning is going to travel if when strikes the building?

It depends where the room is and how it is designed. If it is either below the point where the lightning protection lines feed into the ground or is enclosed in a Faraday cage then they'll be completely safe from lightning strikes.

[Diamon]

That's why we have grounding rods.

And rain :)
It's usually raining when lightning strikes here at least and the rain could provide a nice open freeway for the electricity to the ground.

[mDust]

And rain :)
It's usually raining when lightning strikes here at least and the rain could provide a nice open freeway for the electricity to the ground.

Nah, lightning prefers to strike where it will cause the most damage.

I'm sure insurance companies would love to make lightning rods mandatory on residential homes, but currently it's only a recommendation. No building codes that I know require them, and thus, not many homes have them...at least around here. I guess we don't install them until after the lightning strikes our home...:facepalm:

[x88x]

It also helps when you have lots of taller buildings trees around you...if you're not the highest point, chances are good that you won't have to worry much about getting hit. ...though, I did know a family once who had lightning jump from a nearby tree to their house...