Distance Low voltage needs to be from High voltage
- Thread starter hcbenz
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hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: Distance Low voltage needs to be from High voltage
Well, what are we talking about here? What voltage is high voltage, where is the wiring and what kind. What kind of low voltage wiring and where is it being installed?
-Hal
Well, what are we talking about here? What voltage is high voltage, where is the wiring and what kind. What kind of low voltage wiring and where is it being installed?
-Hal
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: Distance Low voltage needs to be from High voltage
All can be run through the same holes if you wanted to. There is no NEC restriction on spacing.
That said, you may want to maintain some spacing because of hum and noise from the 120V wiring and some LV wiring though I have never seen this to be a problem. Certainly not with coax and twisted pair.
-Hal
All can be run through the same holes if you wanted to. There is no NEC restriction on spacing.
That said, you may want to maintain some spacing because of hum and noise from the 120V wiring and some LV wiring though I have never seen this to be a problem. Certainly not with coax and twisted pair.
-Hal
Re: Distance Low voltage needs to be from High voltage
The separation from "line voltage" depends on a couple of things, both of which depend on your desire to be better than required and how sure you want to be that induction won't be a problem!
The two things to consider are (1) is the wire/cable running parallel? maintain at least 12" . crossing perpendicular or diagonally? at least 3" and for as little length as possible. No code that I'm aware of, but you won't be sorry.
The separation from "line voltage" depends on a couple of things, both of which depend on your desire to be better than required and how sure you want to be that induction won't be a problem!
The two things to consider are (1) is the wire/cable running parallel? maintain at least 12" . crossing perpendicular or diagonally? at least 3" and for as little length as possible. No code that I'm aware of, but you won't be sorry.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Distance Low voltage needs to be from High voltage
"The high voltage is regular 110 120. The low voltage is rg6 cat5 22/4 22/8 ect. It a residential dwelling"
Keep in mind the NEC does not define high and low voltage. To a POCO, 120 is low voltage, to a fire alarm tech, 120 is high voltage.
There is no NEC requirement for separation, NM cable is a wiring method, the same are EMT. If there is no separation for EMT, then the same for NM cable.
However separation is required for proper performance, not in the same stud bay and cross at right angles.
"The high voltage is regular 110 120. The low voltage is rg6 cat5 22/4 22/8 ect. It a residential dwelling"
Keep in mind the NEC does not define high and low voltage. To a POCO, 120 is low voltage, to a fire alarm tech, 120 is high voltage.
There is no NEC requirement for separation, NM cable is a wiring method, the same are EMT. If there is no separation for EMT, then the same for NM cable.
However separation is required for proper performance, not in the same stud bay and cross at right angles.
brannen
Member
- Location
- Charlotte, NC
Re: Distance Low voltage needs to be from High voltage
I believe the 12" horizontal and 3" /90 degree perpendicular seperation are EIA/TIA standards and not NEC.
I believe the 12" horizontal and 3" /90 degree perpendicular seperation are EIA/TIA standards and not NEC.
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: Distance Low voltage needs to be from High voltage
He is talking about separation of wiring within walls and ceilings of a residential building. 725.55 covers separation of conductors and communications wiring in raceways, enclosures and manholes.
Not exactly the same thing.
-Hal
He is talking about separation of wiring within walls and ceilings of a residential building. 725.55 covers separation of conductors and communications wiring in raceways, enclosures and manholes.
Not exactly the same thing.
-Hal
macmikeman
Senior Member
- Location
- Planet macmikeman
Re: Distance Low voltage needs to be from High voltage
I could easily be wrong once again on this but but back when I was an apprentace I was taught that the door bell wiring (two cunductors twisted around each other, no sheath) could not be run thru the same holes as the nm and needed to be seperated by two inches. Now I cannot find any code reference so I am not really sure if this is right or wrong.
I could easily be wrong once again on this but but back when I was an apprentace I was taught that the door bell wiring (two cunductors twisted around each other, no sheath) could not be run thru the same holes as the nm and needed to be seperated by two inches. Now I cannot find any code reference so I am not really sure if this is right or wrong.
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: Distance Low voltage needs to be from High voltage
There is no code reference that would prohibit it.
-Hal
There is no code reference that would prohibit it.
-Hal
luke warmwater
Senior Member
Re: Distance Low voltage needs to be from High voltage
Except in Cecil County, MD.
Their ammendments require the 2" seperation.
Except in Cecil County, MD.
Their ammendments require the 2" seperation.
macmikeman
Senior Member
- Location
- Planet macmikeman
Re: Distance Low voltage needs to be from High voltage
I first went to work down in Fort Myers Fla. I wonder if it was a Lee county requirement.
I first went to work down in Fort Myers Fla. I wonder if it was a Lee county requirement.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Distance Low voltage needs to be from High voltage
Small world
Back in the "70's" I worked for B&R electric off pondsetta west of US41. I worked on the 2, 10 story condo's at the north end of the old US 41 bridge.
Small world
macmikeman
Senior Member
- Location
- Planet macmikeman
Re: Distance Low voltage needs to be from High voltage
Hurk, I was with Three D electric, and later Claude Jansen Electric over in Cape Coral, then last for Sun Electric which I think is the only one still going of the three. I graduated from Cypress Lake High School.
Hurk, I was with Three D electric, and later Claude Jansen Electric over in Cape Coral, then last for Sun Electric which I think is the only one still going of the three. I graduated from Cypress Lake High School.
arjo_reich
Member
Re: Distance Low voltage needs to be from High voltage
Parallel runs of video / data lines should maintain at least a 12" distance to avoid interference bleeding in from the 120/240 circuit runs.
Perpendicular runs are fine, but if you can maintain a 3" distance when going perp to higher voltages the better.
...
The problem is not a regulation of any kind but the fact that both RG-6 Quad shied - as well as any inferior type of coaxial - and any type of unshielded twisted pair (UTP) do not resist the hum that higher voltages give off.
The net result is an increase in attenuation on your video or data lines. On video lines it's often so negligable that you cannot notice it - UNLESS it is for an HDTV run then you'll see a very fast degredation of signal if you don't maintain the distances.
In data networks, on 100 Mbps systems, if you're less than 12" you might notice that you're only getting 70-90 Mbps. However, if you were to run that parallel through the same holes, you may find some of the longer runs only get 10-40 Mbps.
This is because the digital data signals are being lost because of the interference and being forced to be resent from whatever originated the signal.
--
Hope that helps,
R. Joe Reich
As a software engineer, this is one I *can* chime in on...
Parallel runs of video / data lines should maintain at least a 12" distance to avoid interference bleeding in from the 120/240 circuit runs.
Perpendicular runs are fine, but if you can maintain a 3" distance when going perp to higher voltages the better.
...
The problem is not a regulation of any kind but the fact that both RG-6 Quad shied - as well as any inferior type of coaxial - and any type of unshielded twisted pair (UTP) do not resist the hum that higher voltages give off.
The net result is an increase in attenuation on your video or data lines. On video lines it's often so negligable that you cannot notice it - UNLESS it is for an HDTV run then you'll see a very fast degredation of signal if you don't maintain the distances.
In data networks, on 100 Mbps systems, if you're less than 12" you might notice that you're only getting 70-90 Mbps. However, if you were to run that parallel through the same holes, you may find some of the longer runs only get 10-40 Mbps.
This is because the digital data signals are being lost because of the interference and being forced to be resent from whatever originated the signal.
--
Hope that helps,
R. Joe Reich
analarmtech
Member
800.52 Installation of Communications Wires and Cables
(A) Separation from Other Conductors
(2) Other Applications
Communication wires and cables shall be separated at least 50mm (2in) from conductors of any electric light, power, Class 1, non-power-limited fire alarm, or medium power network-powered broadband communication circuits.
Exception No 1: Where either (1) all of the conductors the electric light, power, Class 1, non-power-limited fire alarm, or medium power network-powered broadband communication circuits are in a raceway or in metal sheathed, metal clad, non-metallic-sheathed, type AC, or type UF cables, or (2) all of the conductors of communications circuits are enclosed in raceway.
(A) Separation from Other Conductors
(2) Other Applications
Communication wires and cables shall be separated at least 50mm (2in) from conductors of any electric light, power, Class 1, non-power-limited fire alarm, or medium power network-powered broadband communication circuits.
Exception No 1: Where either (1) all of the conductors the electric light, power, Class 1, non-power-limited fire alarm, or medium power network-powered broadband communication circuits are in a raceway or in metal sheathed, metal clad, non-metallic-sheathed, type AC, or type UF cables, or (2) all of the conductors of communications circuits are enclosed in raceway.
The NEC requires 2" separation (or a barrier), as previously noted. EIA/TIA used to have specific spacing requirements but I believe these have been removed from the more recent versions and replaced with general language along the lines of keep far enough separation to minimize e-m interference.
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