Guys, does anyone have an NEC section or reliable source (pictures or videos would be awesome) of how to combine low voltage (12 or 14 VDC or VAC) and 120VAC or 240VAC in same enclosure?

I have this:


[Link: automationdirect.com]

It works great, but I had to place my 22/2 trigger wire (from Russound's C5 zone 15 trigger out) in the same space as 120VAC that's cutting power off to my Crown CDI1000.

Everything that I have even seen in the code or training stated not to mix low and line voltage.
Somewhere I seen 3 theories:
1. anything under 600VAC is considered low voltage. I always though it was 50.
2. as long as low voltage cable is rated higher than line voltage in that enclosure, we're fine. My line voltage is 120VAC -- the 22/2 is rated for 300V -- am I OK?
3. line and low voltage are mixed in all kinds of applications including HVAC systems (24VAC T-Stat wire into 120VAC furnace); washers/dryers (with LV relays activating motors/heaters) all in same enclosure; 3 phase motors (with their LV starters), etc.


So while this project is in my own house, I want to understand how to do this properly for when time comes to do this at a client's house.

As you've already mentioned, low voltage controls higher voltage in the same enclosure.

I think where the low voltage can't mix with higher voltage stems from the fact they are there not to control each other. So since, in your case and other cases as you mentioned, that the low voltage is there to control the high voltage. It's ok.

But to put the 120 outlet in the same box with the HDMI outlet, then that's illegal.

That's my theory, whether is right or not. I don't know.

KOT

I've read that the low voltage wires should be rated for 600V, if in the same box.

I'm sure there is a 'right' and better way to do this, though, as I've seen relays mounted on the outside of line voltage junction boxes.

It's difficult for me to determine which relay you are using, from that spec sheet link.

If you don't get an answer here, call Automation Direct for some guidance or additional literature. They were very helpful with me choosing terminal al blocks.

The insulation characteristics of the wire connected to low voltage could be the key to having both in the same enclosure.

This gives another reason to call Automation Direct, though. Relay sockets I've seen like the one you show have the common high voltage on one side, low voltage for the coil in the middle, and switched high voltage switched contacts on the other. I believe there must be sockets with high voltage on one side and low voltage on the other side to help achieve physical separation.

For years I've seen Lutron six-circuit controllers with high voltage and low voltage in the same box. It's a deep metal box, to be sure, but high and low are in the same box.

800.133 Installation of Communications Wires, Cables, and Equipment. (A) Separation from Other Conductors. (1) In Raceways, Cable Trays, Boxes, and Cables. (c) Electric Light, Power, Class 1, Non–Power-Limited Fire Alarm, and Medium-Power Network-Powered Broadband Communications Circuits in Raceways, Compartments, and Boxes.
Communications conductors shall not be placed in any raceway, compartment, outlet box, junction box, or similar fitting with conductors of electric light, power, Class 1, non–power-limited fire alarm, or medium-power network-powered broadband communications circuits.
Exception No. 1: Where all of the conductors of electric light, power, Class 1, non–power-limited fire alarm, and medium-power network-powered broadband communications circuits are separated from all of the conductors of communications circuits by a permanent barrier or listed divider.
Exception No. 2: Power conductors in outlet boxes, junction boxes, or similar fittings or compartments where such conductors are introduced solely for power supply to communications equipment. The power circuit conductors shall be routed within the enclosure to maintain a minimum of 6 mm (0.25 in.) separation from the communications circuit conductors.


Exception No. 2 is what you are looking for.

Russound equipment definitions would have to be stretched a damn far way to designate them as communication equipment. Otherwise, yes, #2 would be the proper exception. The same goes for Lutron controllers we've been wiring for years.

The wire separation is the sole part of that section that can be applied.

Awesome, except if there is 6mm separation from these terminals (top is control, bottom is common rail (in my case 120VAC)), that would be really close. Notice the total height of the base is 28.8mm.

Ernie, not sure how I can ensure wire separation in this case and there definitely is no physical separation where one side of base is for line voltage and the other for low voltage.

It may be hard to tell from picture but going in pairs of connectors (DTDP unit shown):
Top set of connectors are normally open relay contacts
2nd from top is a set of normally closed relay contacts
2nd from the bottom is the relay energizing coil, in my case 12VDC
Bottom set is the common relay rail.


But hey, I see a UL certification on the product sheet and the unit itself, so I'm not going to question it.




I just don't see any practical way of ensuring the wiring separation between line and low voltage wires.

Sorry, In this case I'm using [Link: automationdirect.com] 782-2C-12D, because I wanted to seperate both power and neutral connectors. In reality, I could have used 781-1C-12D and just run the power (black) wire thru it.

I love those little guys.
They do look way to small to be able to carry the 15Amp current they're rated for :-)

for the high/low voltage trigger application we use those [Link: functionaldevices.com], connect two 4in. Square metal boxes via chase nipple, make low voltage splices in one box and high voltage in another. So you have clean look with two metal boxes clearly marked and It's NEC compliant .

Honestly I would check with your local inspector to see what they will accept since villages can have their own addendum to national code. Article 725 covers much of your situation.

"Section 725-54(a)(1), Exception No. 2 in the NEC allows low-voltage cables and higher-voltage conductors to be in the same enclosure where the higher voltage conductors are not greater than 150 volts to ground and are introduced solely to connect to the equipment. Where using this exception, the low-voltage conductors must be installed and insulated as Class 1 conductors.

Some installations require that Class 2 or Class 3 circuits enter an enclosure, an outlet box, or certain raceways, such as wireways and surface raceways as covered in Article 352, to enable connecting the circuit to the equipment. These Class 2 or Class 3 conductors or cables must be separated from the power conductors by either a barrier or a raceway within the enclosure. The barrier is normally made of the same material as the enclosure but the NEC does not specify the type of material for the barrier."

[Link: ecmweb.com]

I was going to suggest a simple 12v triggered outlet, e.g. Xantech AC1, until I compared the prices of the relay and the AC1. Heh.

When you wrote 'enclosure', did you mean "inside of the rack or structured wiring enclosure" or "inside of a junction box"? If the latter, the 6mm separation is supposed to be observed, but in a rack, I don't think I have ever seen DIN rail with relays where the terminals were more than 6mm apart, although the LV and HV wires were bundled separately and kept apart.

Both, although I'm wondering if this can even be installed in the rack or SMC.
If you look at the base module, there is no way to conceal the terminal screws ,although they are recessed, or the wire ends. This is very similar to circuit breaker, albeit on a smaller scale.
I would bet money that this has to be installed inside an enclosure and not in an open field, which coincidentally is how I had installed my 2nd unit; Oops :-0

As I understand it, "exposed screws" means they're outside of the plastic housing, so anything that could come into inadvertent contact, can. These are recessed and someone would have to try to access them.