# Low Voltage/ High Voltage



## MikeD

i posted this under another thread....i'm new to this so i'll post it here as well....
can anyone help me here?....i'm wiring a house and i have high and low voltage cables running through the same holes in the studs...i've asked soem people and they said that this is ok...i've read that because of the way that the cat5 is wrapped, this eleiminates interference from high voltage romex...but what about the co-ax?....will I have problems???????


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## 480sparky

MikeD said:


> ...but what about the co-ax?....will I have problems???????


Co-ax is short for co-axial. Meaning one conductor is wrapped around the other. The center conductor carries the signel, the outer conductor is the shield.

Unless you run them parallel for quite a distance, you generally won't have any problems.


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## MikeD

thanks....


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## yankeewired

*Not a violation*

Cat5 and coax can be installed thru the same bored holes. Bored holes are NOT a raceway therfore it is allowed however TIA standards differ from the NEC . It's not the best practice to run paralell to line voltage conductors, try and avoid if it's possible. Both types of cables are by design resistant to emi (electromagnetic interference) and rfi (radio frequency interference) however If you get a customer who wants every ounce of performance out of their network you could be causing yourself a big headache that can be easily avoided during your rough -in .I personally stay one stud away and have had IT guys test the install for data transfer rates and have passed nicely. Also, watch out for any sharp bends in you runs.Lastly If your terminating the cables make sure they are done to the standards, It will easily fail if utp is untwisted too far for example.


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## wirenut1110

We interpret that as conductors through holes, staples, whatever is the same as conductors through conduit. As long as they have the same voltage rating ie. 600 volts, then they can be. The 3 houses I've ever wired in my ife, I never ran high and low in the same hole, not even the same space to eliminate call backs (whether my problem or not) seems like it's never been proven but common sense. When it comes to phone/data and coax, even in residential, i've just always run homeruns for ech "drop" and ran them away from everything else so when the customer called back I could honestly say "not my problem"


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## Idaho Abe

*Coax cables*

Make sure that you listed cables. In our area the cable companiews will not hook up to non listed cables. It is also a NEC violation.


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## rivalshad

It can cause packet loss in cat5/6 cabling when used on computers using TCPIP. I can't give you the exact code but I'm pretty sure there is one stating that low voltage wiring can not be in the same raceway as high voltage conductors.


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## cdnelectrician

Baaaad practice! The CEC prohibits this!


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## pudge565

Just went over this in Tech today must be 3' away from the high voltage. Not sure of the code section but it is code.


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## Billy_Bob

When running low voltage cables along with the electric cables, it is sort of like listening to AM radio in your car when you drive under a power line and get that bzzzzzz sound...

For that reason, I like to run my low voltage cables away from the electric cables as much as possible.

Also with coax cable, there is cheap cable and good quality cable. The cheap cable has poor "shielding", and the more expensive cable can have 4 layers of shielding like RG-6 Quad shield coax cable.

I think you can get just about any low voltage cable which is shielded. This costs a young fortune though.

As an example where this may not matter or could matter is a doorbell! In years past it was a simple ding/dong electro-mechanical switch. Shielded cable would be a waste of money. But these days, wired doorbells could be electronic. These can pick up a "hum" from doorbell wiring which is run next to electrical lines. Shielded doorbell wiring and running the doorbell wire away from electrical lines should keep the hum out or drastically reduce it.


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## Kletis

pudge565 said:


> Just went over this in Tech today must be 3' away from the high voltage. Not sure of the code section but it is code.


If you are referring to National Electrical Code I think that this statement is incorrect. Please let me know if you can find a reference because I would like to know.

Having said that, it is poor practice to run them near each other. When I used to rope houses I would run my low volt conductors a couple feet away when possible and on the next stud bay over going down the wall. Sometimes this did not work out, but I did whenever possible.


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## Jim Port

Like others have said it is not a Code violation, but, do feel it to be a poor practice. I believe BICSI does have something in their wiring standard, but I think it requires 12" seperation.

Here is a graphic from Mike Holt.


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## pudge565

You guy are right I asked him and told me it is a manufacturer recommendation. When he taught it he told us that it had to be 3' away so i took it that it was code.


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## kawaikfx400

We NEVER run co-ax or cat5 within any holes with high voltage. TO much of a risk of a callback. I beleive you can cross at a 90 degeree angle and your ok. But definitely cant run parallel or through the same hole. Good rule to follow.


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## Nosparxsse

Nope never.:no:

good way to get that call saying, "Hey when someone calls I hear this Buzzz in the backgound."


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## Misha1980

I'll ask here as it's along the same lines. Is there a code prohibiting Fire Alarm Circuits and Data lines from being in the same Cable tray? I know the IDnet lines on a simplex system are low voltage, and shielded, but if I put a probe up to one I can here the signal louder than all get out. Just curious about this, it came up on the last job I was on. I recommended running them separately, our low voltage foreman said it was fine....everything did certify to CAT6.


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## Node

kawaikfx400 said:


> We NEVER run co-ax or cat5 within any holes with high voltage. TO much of a risk of a callback. I beleive you can cross at a 90 degeree angle and your ok. But definitely cant run parallel or through the same hole. Good rule to follow.


Exactly like he said
And I always do 12" apart if ran in parallel, if not a little more. Never anything like 3', but its not a bad idea if you think of it. Never hurts for that extra bit of overkill.


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## Howieburk

You can run low and high voltage in the same raceway if the insulation on the low voltage wiring is rated no lower than the highest voltage in that raceway.


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## volty

*Mixing different systems*



Howieburk said:


> You can run *low and high* voltage in the same raceway if the insulation on the low voltage wiring is rated no lower than the highest voltage in that raceway.


Kind of, in theory, but almost never in practice:
411.3(B)(3), Lighting systems 30 volts or less ("low voltage"),
600.32(A)(2), Neon secondary over 1000 volts ("high voltage"),
630.42(C), Welding cables ("lower voltage"),
640.21(B or C), Audio systems between equipment, amps, speakers ("low voltage"),
725.136(A), Class 2 and 3 ("low voltage"),
760.136(A), Power-limited fire alarm ("low voltage"),
770.133(A), Conductive optical fiber cables (NO voltage),
800.133(A)(1)(c), Communication wires and cables ("low voltage"),
810.18(B), antenna lead-in conductors, ("low voltage"),
820.133(A)(2), CATV ("low voltage"),
830.133(A)(1)(d), Network powered broadband ("low voltage").
Can't do it.

647.4(B), Sensitive Equipment ("lowish voltage", 60 volts).
Probably.

620.36 Elevators
725.48(A), Class 1 circuits ("low or high voltage") (Chapter 3 methods).
OK

So 300.3(C)(1) does allow the mixing in general, and you might make use of it sometimes, but as 90.3 shows, chapters 5, 6, and 7 modify chapters 1 through 4. That makes it rarely useable for most of us.

It is best for most of us to discard the phrases low voltage and high voltage. Over 600, 1000, or 1500 volts, depending on location and type is considered "high voltage", while 480 volts should be considered "low voltage", in the big picture.

Of course if you're working on a digital chip, 4 or 5 might be high, so context always matters. Using the true system designations can help us look for the actual code sections that apply.:thumbsup:


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