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#10372 - 06/07/02 08:27 PM help needed with low volt/home automation wiring
teeland Offline
Junior Member

Registered: 05/12/01
Posts: 4
Loc: Hot Springs, AR
Hope you guys can help me here.

I am almost finished wiring a nice, no cost spared home when the homeowner brings out a home automation contractor to pre-wire the home. I of course stick my nose into the situation because I know that this is going to involve my work. The home automation guy tells me that he is going to daisy chain a 2 conductor, 16 guage wire to every one of MY switches in the house. This is where I almost lose it, but I calm down enough to listen.

Well, I am not at all knowledgable in home automation, but I told him that low volt wire is not permitted in the same box as line voltage. After being assured that he would not mess with my work, I told him that I would check out the NEC to see if there was some kind of application where this is possible.

Here are my questions to all of you "code guru's".

I started at article 725.55 and found that I could use class 1, 2 and 3 wire in switch boxes if they were seperated by a minimum of 1/4" or a non-conductive sleeve. Am I mis- reading anything here or is this my solution?

So after this I keep reading my code book and find article 780-Closed loop and programmed power distrubution.
I thought I had it all figured out now. You can share the same box if you use a hybrid cable. My problem here is I do not understand what a 'hybrid" cable is. This article is small and simple except for my ignorance is this type of wire.

I am now very interested in this application and want to learn more about home automation. I do have a problem however with non-licensed people having access to and working on our devices.

Thank you for any information you guys can give me!

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#10373 - 06/08/02 09:32 AM Re: help needed with low volt/home automation wiring
The Watt Doctor Offline

Registered: 12/23/01
Posts: 443
Loc: Mont Belvieu, TX
If you are worried about different voltages in the same in enclosure, raceway, etc, notice the following: 300-3 (c) Conductors of Different Systems.
(1) 600 Volts, Nominal, or Less.
Conductors of circuits rated 600 volts, nominal, or less, ac circuits, and dc circuits shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway. I would "hit up" some of the guys that know about resi installations. I want to Redsy, sparky, and sparky66wv are up on these installations. Cindy posted a message about these setups as well.

Good Luck,
The Watt Doctor
Altura Cogen
Channelview, TX

#10374 - 06/08/02 10:20 AM Re: help needed with low volt/home automation wiring
resqcapt19 Offline

Registered: 11/10/00
Posts: 2209
Loc: IL
The control wires would be covered by Article 725 and in many cases can not be mixed with the power conductors no matter what the voltage rating of the insulation is. There is a FPN after the section that you cited to refer you to Article 725.

#10375 - 06/08/02 11:12 AM Re: help needed with low volt/home automation wiring
sparky66wv Offline

Registered: 11/17/00
Posts: 2334
Loc: West Virginia
I've only been in one house (mansion) that had lowV switches controlling 120V lights. It was an old, but well installed system, and had a neat doorbell/pager with numbers that dropped down according to which door was ringing. It was all a bunch of relays, contactors, and lowV wire strung everywhere, but no voltages were mixed except in the control wiring box. I made some routine repairs and it still works great!

I haven't had the opportunity to deal with anything modern. The Greenbrier houses have releatively normal wiring, with VDV/Audio guys doing their thing. What they do is some pretty fancy stuff! ...Invisible speakers in the ceiling (better make good connections the first time!), huge HDTV sets, sound system controls in every room (that sounds like crap, my computer has much better bass response on a $60 sound system!), intrusion alarms system and intercom...

None of it is my resposibility, thank goodness!

#10376 - 06/08/02 11:59 AM Re: help needed with low volt/home automation wiring
Cindy Offline

Registered: 06/23/01
Posts: 196
Loc: PDX, OR, US
sorry dont know that much, but the NMS cable i dont think is made anymore, and the flat smart house wire with coax and 12awg and class 2 & 3 cables in the jacket i thought they went out of business too. check this article out, its several months old but has a point of contact at UL and summarizes things pretty well
and this is a SCS system self-promotion but has some good info
walker duct and 4000 series divided molding are ok and using barriers might be ok too. depends on what the 16awg is used for? class? txfmr?
6mm separation might work..... 1/4" ??? i've heard of that before ???? must be some kind of archaic measurement system

#10377 - 06/08/02 12:06 PM Re: help needed with low volt/home automation wiring
Currently Offline

Registered: 04/21/02
Posts: 54
Loc: TN
Dunno much about residential automation but I do know industrial automation. You do not want to mix the two together. Some things to avoid are florescent ballasts, dimmer switches, motors ... etc. Analog signals can be skewed by proximity to these devices.
Discretes are less affected. May want to cover your *$$ by completing the job and getting the inspection signed off before allowing any changes to be done by this guy.
A few photos of potential problem areas before the changes may also cover you.

While I don't have any and don't want any automation in my home, it is coming and within the next 5 years it will be flooding the market. The cost of equipment is going down and will decrease even faster due to economies of scale in the near future. Appliances are being designed as we speak to have embedded operating systems. This will not reduce the need for sparkies, in all probability increase the workload and for those who want to enhance their skillsets will open up to a market that will blow wide open. The impact will be as great as personal computers did for workplaces. (Remember the promises of paperless offices )

Apologizing for getting on my soapbox. I'm in the middle of seeing some unbelievable products being released by my company right now. Small, cheap and powerful.

[This message has been edited by Currently (edited 06-08-2002).]

#10378 - 06/08/02 02:39 PM Re: help needed with low volt/home automation wiring
Bjarney Offline

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
An example of dealing with "partitioning" between 600V and non-600V compartments are touchplate controls, which fit in a ½-inch KO in the dividing wall.

Fairly sure that they are also intended to be mounted in a KO in a ~4-square box with the 24-volt side bellwire leads “floating.”

Is the other guy's stuff listed/labeled? If it isn't, raise heck. If they are, the instructions packed with his stuff should have unambiguous, code-compliant installation methods.

[This message has been edited by Bjarney (edited 06-08-2002).]

#10379 - 06/08/02 08:24 PM Re: help needed with low volt/home automation wiring
eesparx Offline

Registered: 01/21/02
Posts: 26
Loc: Colorado Springs, Colorado
I install home automation & structered wiring packages as part of my eletrical services. The following link will show some of the products I use:

#10380 - 06/10/02 03:56 AM Re: help needed with low volt/home automation wiring
Redsy Offline

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA

Is this a Leviton system?
If, so try and follow the menu to LIN systems. (Also try
I haven't installed them, but I know someone who did.
Some of the systems are designed to operate with low voltage & line voltage in the same wall case.
When in doubt, contact the AHJ for prior approval.

#10381 - 06/10/02 04:14 PM Re: help needed with low volt/home automation wiring
sparky Offline

Registered: 10/18/00
Posts: 5545

These do last a while, as i have services some homes in the area with them, (must have been a fad 30 yrs ago??)
I agree with the group here, listings & AHJ should previal

IMO, Home Automation works best preconcieved, not as a retrofit. Because it has been renewed as a novelty, there seems a wide range of product , and an even wider range of expertise, as well as the sales pitch to go with it.

I got into it with one 'automation' guy who installed these. Seems he could'nt use the grounding prong of the 3-cord male cord caps, and adapted them out.......

The solution was, at the time, to document said problem and forward it to the customer.....


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