# 12/2 Speaker and Cat5e in EMT



## McClary’s Electrical

As long as it's not feeding an amplified speaker I guess it would be fine. I guess it would also depend on what's flowing on the CAT V.


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## Hawkeye_Pierce

mcclary's electrical said:


> As long as it's not feeding an amplified speaker I guess it would be fine. I guess it would also depend on what's flowing on the CAT V.


the cat5e is getting standard network traffic and the speaker run is between an 8ohm speaker and a 400w amp. 

Some of these runs are 50 - 100 feet 

I figured since the network traffic is cooking at 350mhz and the speaker more 20kHz or less that I wouldnt have a problem


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## guest

How critical is the application?

How much work will it be to come back and install a second conduit when there is a problem?

I can tell you from years of doing A/V work that you are setting yourself up for trouble putting them in one pipe, especially with a 400 watt amp driving an 8 ohm load. 

Best to keep them separated. You can easily induce interference in the CAT 5 with that much audio power.


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## Hawkeye_Pierce

mxslick said:


> How critical is the application?
> 
> How much work will it be to come back and install a second conduit when there is a problem?
> 
> I can tell you from years of doing A/V work that you are setting yourself up for trouble putting them in one pipe, especially with a 400 watt amp driving an 8 ohm load.
> 
> Best to keep them separated. You can easily induce interference in the CAT 5 with that much audio power.


I guess this is the informed answer I was looking for. I figured there wouldnt be a problem but its early enough in the game to run two pipes. Just didnt want to waste time if it wasnt necessary


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## chewy

We have the AV guys come and run on our trays and catenarys all the time with no issue but have never had them in the same conduit if that would make a difference I'm uncertain.


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## rnichols

I know job specs for walmarts,targets,etc calls for seperate pipes and for them to be on opposite studs in their own boxes.. I have taken a toner wand to cat5 that was in the same pipe and I could hear the audio bleed over to the cat5 when it was in the same pipe..


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## guest

chewy said:


> We have the AV guys come and run on our trays and catenarys all the time with no issue but have never had them in the same conduit if that would make a difference I'm uncertain.


Then things must work differently in your galaxy or else you've just been one lucky Wookie. :laughing:


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## zappedjack21

You have to keep all High Voltage and Low Voltage wiring seperate. Thats what it says in the National Electric Code. Of course there will be interference. Why take the time and effort on trying when it might not work at the end... Good luck..


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## Hawkeye_Pierce

zappedjack21 said:


> You have to keep all High Voltage and Low Voltage wiring seperate. Thats what it says in the National Electric Code. Of course there will be interference. Why take the time and effort on trying when it might not work at the end... Good luck..


Speakers are LV


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## chewy

mxslick said:


> Then things must work differently in your galaxy or else you've just been one lucky Wookie. :laughing:


Hmm, They put their amps and other Toa gear in our cabinets aswell... everything scans through fine on the Fluke and no problems to date, perhaps thats a scab best left unpicked. :laughing: I'm not too familiar with all the AV and Intercom stuff but everything we do gets certified on a Fluke DTX 1800 and results given to the client for their warranty.


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## Speedskater

If the speaker wire is carrying audio frequency signals and the CAT5 is carrying high frequency digital signals, what's the problem.

Side-note:
Interference wise twisted pair cables are better than well dressed zip cords.
The same goes for Romex® (NM), messy is better than tidy.

But if the CAT5 is carrying old fashion telephone or intercom or alarm signals, the story could be much different!


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## guest

Speedskater said:


> If the speaker wire is carrying audio frequency signals and the CAT5 is carrying high frequency digital signals, what's the problem.


The problem is simple: any MEASURABLE crosstalk WILL result in signal degradation and the effects can be and frequently are unpredictable. In the case of data, it can result in excessive data errors which may or may not be correctable, but waste any of the digital system's error correction capability. In the case of audio, depending on many factors, it can cause amplifier instability, audible artifacts or possible speaker damage if the amplifier becomes unstable and oscillates. (older gear and the overpriced P.A. gear like Bogen, etc. are VERY susceptible to instability induced by bad wiring practices.) 

I have run into a LOT of installations where speaker lines were incorrectly installed and resulted in all kinds of problems from amplifier and speaker failures to feedback and audible noise and oscillation. 

And IMHO the problem is with people who have the attitude of "what's the problem" when they are advised on the right way to do things, they go off and ignore the advice, then come back whining because they ran into the very problems they were warned about. :whistling2::laughing: I ran into this situation with a discussion on Digital cinema servers.


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## Speedskater

I started doing broadcast engineering and pro audio engineering in the mid 1960's. While much audio equipment had design problems in the switch-over from tubes to transistors, that was a long time ago. With more modern equipment, I would not be the least bit uncomfortable running cables and CAT digital cables near each other.


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## guest

Speedskater said:


> I started doing broadcast engineering and pro audio engineering in the mid 1960's. While much audio equipment had design problems in the switch-over from tubes to transistors, that was a long time ago. *With more modern equipment, I would not be the least bit uncomfortable running cables and CAT digital cables near each other.*


And for line-level audio cabling I can agree 100% but in this case we are talking speaker lines driven by a 400 watt amplifier. You do the math to see the current and voltages reached at that power into an 8 ohm load. 

In fact in my latest install for digital cinema I have CAT6, Video and Line level audio all crammed into the same conduit for a run of 50 feet and it is not a problem at all. It is only when power or speaker lines are involved that separation is mandatory. 

It is NEVER a good idea to have speaker - level cabling and anything at lower signal levels in close proximity even with modern equipment. 

A note to those who may not know, in audio "Line-level" is usually all signals PRIOR to amplification for speakers. (Loosely speaking.)


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## zwodubber

This is kind of off the main topic but I use 16/2 with 2 pair UTP siamese cable for some security camera installs. I just ran four runs through 80' conduit and had no signal degradation. They make this with more UTP pairs also...


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## guest

zwodubber said:


> This is kind of off the main topic but I use 16/2 with 2 pair UTP siamese cable for some security camera installs. I just ran four runs through 80' conduit and had no signal degradation. They make this with more UTP pairs also...


Yeah but that 2c is for the (usually) DC camera power and it is designed for the application. 

But thanks for posting it I am sure that someone will find that cable spec useful (I saved it for future use.) :thumbup:


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## zwodubber

mxslick said:


> Yeah but that 2c is for the (usually) DC camera power and it is designed for the application.
> 
> But thanks for posting it I am sure that someone will find that cable spec useful (I saved it for future use.) :thumbup:


Yep, just wanted to bring it up because it's not a common combination people are aware of and it can be great in certain applications.


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## BenRush

*Running Amplified Audio with Network Cabling*



Hawkeye_Pierce said:


> Anything wrong with running speaker wire and Cat5e in the same conduit? Will it cause interference?
> 
> IMO two separate LV conduit runs to the same drop locations seems like a waste of time . . . just wondered if anyone knew better


Well, on a small commercial building I did an install where I ran Cat5e along with 16awg/2c cabling. Both un-shielded. There was only a small space around the perimeter of the ceiling (exposed ceiling and exposed brick walls) in which to run the low voltage cabling, this space was later covered. After completion, at the Network/phone drops an inductance wand was placed at two of the four network jacks and the music was *most definitely* and prominently "bleeding" over. I did not, however, run the speaker and network cable in the same EMT conduit at the individual drops. 

The speaker cables were coming off of a 70 Volt output on a commercial Bose amplifier and going to five speakers. 

I have run and seen other low voltage audio run along side network before, but this is the first and only time I've seen this happen. Maybe, because my cables were run so many and so tightly together. 

_So, there you have it. It can happen. The question is, how harmful is it to network traffic? _


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## BenRush

BenRush said:


> Well, on a small commercial building I did an install where I ran Cat5e along with 16awg/2c cabling. Both un-shielded. There was only a small space around the perimeter of the ceiling (exposed ceiling and exposed brick walls) in which to run the low voltage cabling, this space was later covered. After completion, at the Network/phone drops an inductance wand was placed at two of the four network jacks and the music was *most definitely* and prominently "bleeding" over. I did not, however, run the speaker and network cable in the same EMT conduit at the individual drops.
> 
> The speaker cables were coming off of a 70 Volt output on a commercial Bose amplifier and going to five speakers.
> 
> I have run and seen other low voltage audio run along side network before, but this is the first and only time I've seen this happen. Maybe, because my cables were run so many and so tightly together.
> 
> _So, there you have it. It can happen. The question is, how harmful is it to network traffic? _


Update:

I have activated all of the network jacks in the building and am using them despite the fact that they have music "bleeding" over. No significant problems yet. 
I also emailed a colleague who is an electrical and cabling application engineer with Honeywell, and this is what he said: 

"Whenever cables are run parallel to each other and in close proximity, there is a chance for an induced current from one cable to another. A current on the speaker cable creates a magnetic field that circles around the speaker cable. The Cat 5e cable, in close proximity to the speaker cable, is in the magnetic field. This magnetic field induces a current onto the Cat 5e cable, which is why you detect audio from the Cat 5e cable.* Obviously the induced current doesn’t help performance of the network, but the amount of harm caused won’t necessary be crippling either*. The length of the runs as well as a few other factors will ultimately determine that."

So, the short of it is. Doesn't help but probably doesn't hurt that much either. With an emphasis on "probably", I would say.

All of this is moot, however, in light of NEC code:

NEC 2005 introduced 
a new article 725.56(F) that prohibits audio cables 
(speaker, microphone or line level signals) to be run 
in the same raceway with other Class 2 or Class 3 
circuits (low-voltage power and network cables)
-Bicsi News Jan/Feb 2008


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## bingo.ca

It's fine running them together.
Most homes wired for distributed audio have a 4 con speaker wire run along a cat5e cable for every zone.
A lot of wire manufacturers even have these together, either bonded to each other or in a single jacket. 

Liberty Wire: http://www.libertycable.com/prod_details.php?pitem=AUDIOCAT-SIAMESE
http://www.libertycable.com/prod_details.php?pitem=AUDIOCAT-14

&

Vertical Wire: https://verticalcable.com/productsdetail.php?id=294-2173&cat=25&sub=26

Also keep in mind that even though an amplifier may be rated to 400 watts per channel at 8 ohms from 20Hz-20kHz, this is a max output rating. Most background listen levels will use less than 10 watts of power and lousd-ish levels use less than 50 watts. This also depends on the speaker specs as well and the listening levels in a given air space.


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## BenRush

bingo.ca said:


> It's fine running them together.
> Most homes wired for distributed audio have a 4 con speaker wire run along a cat5e cable for every zone.
> A lot of wire manufacturers even have these together, either bonded to each other or in a single jacket.
> 
> Liberty Wire: http://www.libertycable.com/prod_details.php?pitem=AUDIOCAT-SIAMESE
> http://www.libertycable.com/prod_details.php?pitem=AUDIOCAT-14
> 
> &
> 
> Vertical Wire: https://verticalcable.com/productsdetail.php?id=294-2173&cat=25&sub=26
> 
> Also keep in mind that even though an amplifier may be rated to 400 watts per channel at 8 ohms from 20Hz-20kHz, this is a max output rating. Most background listen levels will use less than 10 watts of power and lousd-ish levels use less than 50 watts. This also depends on the speaker specs as well and the listening levels in a given air space.


Yes, that is common to run a Cat5e next to a 4 conductor speaker cable for Residential distributed audio. However, the Cat5e conjoined with or run along side of the speaker cable is not used as a network cable, which brings up the real question at hand, whether or not one should run a network or communications cable in the same raceway as an audio cable.
NEC code 725.56 clearly dictates that audio can not be run in the same raceway with network cabling.
The Cat5e, in a residential distributed audio application have been re-purposed by the industry as a cable to transmit control and IR signals and sometimes the audio signal as well as in the case of an A-bus type system. So, essentially they are not network or communications cable in that application, even though they are categorized as such.
Basically, the wiring method or cable used is dependent upon the purpose of the circuit and not the cable type. 
Hope this makes sense.


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## Jefe

NEC 725.56(F) aside, category computer network cabling uses balanced, differential circuitry to detect the voltage DIFFERENCE between the two conductors in a twisted pair. When twists are maintained all the way up to terminations in the jacks/receptacles and plugs used in face plates, patch panels and equipment the near and far end crosstalk (NEXT/FEXT) and susceptibility to Alien crosstalk (AXT) should be zero. i.e. speaker wire next to Category structured cabling should not cause a problem.

IEEE 802.3 Ethernet communicating across TIA-568-C cables uses 4D-PAM5 pulse amplitude modulation over 4-pairs with five voltages, −2 V, −1 V, 0 V, +1 V, and +2 V at the drive pins and typically half that voltage across the 100 ohm impedance cables through the isolation transformer couplings. 

Having been shocked (not electrocuted) from 70.7V audio output I appreciate why the code requires separation, perhaps in order to visually inspect in the case of a problem, but that doesn't explain why the 90 volts AC at 20 Hz ringer of a POTS circuit is allowed. 

The rationale for separating speaker wiring from control wiring is, should the speaker wire insulation fail along with the signalling and remote-control insulation fail the system controlled or monitored through the signalling and remote-control to also fail. Excessive induced AXT voltage could cause the common mode rejection circuitry to fail. 

Coax, shielded twisted pair, and Cat cables are often bundled together in a single trunk run across entire buildings through J-hooks or zip tied to rafters.

What the magnitude and probability of voltage from capacitive coupling of nearby electric fields (E); inductive coupling of local magnetic fields (M); electromagnetic coupling of radio signals in space (EM); and conduction through intentional or sneak circuit paths (C) is in conduit versus outside of conduit is anyone's guess. 

An AHJ inspector with too much time on their hands and having a bad day with a string of incompetents theoretically could look at each device in a computer/telecom room/closet rack for PA/mood music amplifiers and observe whether the speaker wires are run in the same conduit as the Cat 5/5e/6/6a/7 structured cable for PCs, VoIP, WAPs, IP cameras, PoS, alarm system, access control, and fire alarm.


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