Is it safe to tie wrap electrical cords?

[bgclarke]

Not sure where this should have been posted, but this section seemed to be the closest for the subject.

I have a small rack that has 7 devices in it, plus 5 devices in my TV stand. The electrical cables for my devices are a mess, with most of then just laying bunched up on the floor.

Is it safe (magnetically and fire wise) to bunch up each individual cord and use zip ties to shorten them or just leave them loose like they are now?

[Jake]

I think running parallel is better then coiled. Also, I would recommend velco ties. A lot easier to adjust or add a cable later on. Dollar store usually is a good place to find them.

[57]

If you're talking about "coiling" up an electrical cord and then using a tie to "shorten" the cord, so that it's basically similar to when you bought it (coiled up except for a couple of extra feet uncoiled), this is not a good idea, because it can concentrate the heat into a smaller volume. Best to leave them uncoiled, or perhaps one long loop, instead of say 5-10 loops tied.

It also depends on the power draw of the coiled cord. If it's only going to a STB (say 20-30Watts), that's a lot different from a large HDTV at 300-400 Watts...

Power cords should be separated as much as possible from signal cables, and they should run perpendicular to each other when possible.

I basically let my cords, cables "hang" from the back of each device on my rack.

[hugh]

Learned something new today!

[Steve0]

this is not a good idea, because it can concentrate the heat into a smaller volume.

Is that correct? Why are your cables creating heat? Shouldnt you be using heavier guage if they are creating heat?

I would of thought if there was a reason to argue against that, it would be that coilinng will add inductance to the wire. I have my doubts how significant that would be though.

If you do decide to use zip ties, dont pull them to tight, because you could damage the insulation on the cables.

[57]

Originally Posted by Steve0

Shouldnt you be using heavier guage if they are creating heat?

Most people use the electrical cords that come with their equipment. If the equipment draws a lot of power, they can get a bit warm due to the resistance. Although a heavier gauge has less resistance and will not get as warm, I don't know many people who replace their electrical cords going to their equipment.

[Stoakley Audio]

Just make sure if you're going to run your power across audio or video lines to cross at 90 degrees. For my rack, I ran all my power seperately and video/audio seperately and then crossed at 90 degrees when I had to.

It's what we also do when running lines from TV mobiles to patch rooms and so on.

Cheers!

[JohnnyG]

Definitely takes Stoakley's advice with regard to power and signal cables!

I'm not sure that heat would ever be a concern, but you should never coil cables that carry any power, because that creates an electromagnet and electromagnetic interference is not something you want in your AV system!

[bgclarke]

Thanks for all the info guys.

Definitely learned a lot from that question.

[donimo]

I'm not so sure about some of these points, but I'll throw in my 2 bits as well

-If your power cable get even warm to the touch, get better ones as these ones are either flawed or greatly insufficient for the task. This goes for ANY electrical device you have (short of say a pocorn maker, electric kettle etc, as these have special "heater cables")

-an electromagnet and electromagnetic interference are 2 different things.

-ideally it would be best to shorten each cable to suit each device.

-finally, you gots to be runnin some mad pimpin gear to even notice any EMI effects that might theoretically occur from coiled cables etc. Mine are folded and velcroed behind the cabinet and upscaled dvd's look perfect, as does the sound. If you were truly concerned about it, buying gear to filter/sheild out the noise would be the best route, as even standing in the middle of a feild you can measure 60hz with an occiliscope and your fingers (personally tested).

Just my 2 cents, like I say.

[Chevalde3]

From an electrical engineer standpoint:
-Power cables can be tie wrapped flat loosely (away from any signal wires below) without any problem but be shure that the insulation is not kinked with the Tye-wrap
-Coax/shielded audio, video, SPDIF or RF type should never be coiled tightly (under 30 cm diam.). You will probably kink the internal insulation (between center conductor and shield) and change the electrical characteristics which is bad for ghosting(video +RF) or high frequency cut-off (audio). These and the next one are sold in such configuration at the store but they shall never be flat tie-wrapped
- Never coil fiber optic (TOSLINK) even if it is seen sometimes under a 50 cm diam.
- Cheap zip cord speaker can be coiled but not expensive ones
*And please dont let the cats/puppies chew them up. They can be "zapped" badly on high current/voltages amps or power cords
Of course I do personnally leave all my cables falling in the back of the furniture like most of you because tie-wrapping loosely takes too much space behing the components but if you can: do it!

[Bent]

Originally Posted by Steve0 View Post
Shouldnt you be using heavier guage if they are creating heat?

A coiled cord wound once essentially doubles it's thermal density - if you were carrying 2 amps over the length of the cord and wrapped it once so it was in contact with itself for a full turn, you'd have the equivalent of 4 amps in the same space.

We've done impromptu experiments were a 100 foot spool of SJTOW (oil resistant extension cord cable) had a male receptacle installed on one end, and a female on the other. It remained on the spool wound as tightly as it came from the factory and witnessed that by carrying a 5 amp load (a construction/worksite halogen light) it would get warm enough to melt and start to smoke within 6 hours when indoors. A fire would have followed shortly thereafter.

[bhowden]

Wow! Although I would never have guessed at the result, I cannot argue with your real world experiment. Do you know the guage of the extension cord you were using?

To pick nits a little bit, I don't think a doubled wire would be equivilent to double the aperage. Power (ie heat) is I squared * R. The resistance (R) is the same so doubling the wire up would double the heat in the same area, not quadruple it.

Brian

[Bent]

To nitpick in return, I didn't anywhere in my post say doubling up a conductor would quadruple anything, I said that looping a conductor around a loop for one full turn, that you'd have double the thermal density... watts/unit of surface area would go up (essentially double), the concentrated heat within the double wrap would be twice that of a single run. Multiply this by a factor of 100 (or more in my test run's case where there was more than 100 turns) and there's nowhere for the heat to dissipate.

The cord we used was #14 copper, a Leviton male plug on one end and a Leviton female plug on the other - more than adequate for 5 amps, at least when not in tightly coiled configuartion.

[catalin]

I as well wouldn't think that coiling wire would cause increased heat or any kind of serious problems. Anyone ever thought of asking the manufacturer of the equipment?
If they're designing the wiring to be coiled up 'flat' then I wouldn't think they'd be a problem.