combo... high and low voltage wall switch?

[kleach]

I have a gas fireplace with a blower. The blower is 110 the gas switch is 24v. Only 6 ft away or so.
I have gone through several home depot double switches..
they last for a very short time... then the static or interference takes over...
I would like to know if there is a switch on the market that has the built in proper protection between the high and low voltage in the same switch.
I want to "light switches" one for the blower one for the fireplace on the same faceplace...
does this exist or do i have to build it?

-Ken

[darthvader]

This is done all the time with 2 single pole light switches in a double box

[kleach]

I was trying to make this happen in a single box (top and bottom)

[darthvader]

ah, i don't know, i have never seen it done before

[uniservice]

I was trying to make this happen in a single box (top and bottom)

They make a single box double wall switch, spst. Cover is the same as a duplex receptacle. Look at Cooper, #271V Johnstone has em........

[billygoat22]

You could use a double switch like above poster- looks like duplex outlet but w/ switches.

Some have a tab that needs to be broke off to separate the two switches since they come with a jumper on the "supply" side to power off a single wire. Break the tab off for separate power supply/circuit.

[billygoat22]

Does the switch fail, or just some wacky stuff w/ the logs?

[hearthman]

Against NEC to have low voltage in same box as line voltage.

[uniservice]

Oops. Forgot about the NEC. Hearthman is right!!!!!!!!

[nchvac]

Seems it would be against the NEC, but I can't think of anywhere that Millivolts DC is mentioned in the NEC. But if it shorted out, it would kill the valve and be a hazard on 18 gauge wire to be carrying 15 amps of breaker capacity, so I am sure it is against the code.
I worked on one this morning with one switch for the fan, 1 for the Low voltage DC and a recepticle. I had to change out the control switch because it had a ohm reading varying from 1 to up to 50 ohms, depending on what I have no idea. Lady couldn't get the unit to work yesterday and went down stairs this morning to find the logs on. The high ohm readings are too much for the thermopile to overcome. Changed switch and it works good now.

[pacnw]

Against NEC to have low voltage in same box as line voltage.

If it is against code, and I know that some have referenced a section, then why is it allowed/passed in EVERY home I go into? I have worked on 10-12 the last couple weeks, all newer construction (<5 years old).

My unit is this way, individual switches in double gang box, one for fan and one gas valve. I read somewhere that there is a divider that can be installed to separate the 2, is that good enough?

I have noticed a couple that the gas valve was run in 14/2, marked low voltage though, would this make a difference in code?

[nchvac]

No one has referenced a section. Though I do not deal with DC wiring, I am a licensed electrician, and will point out what I have located in the code in about 10 minutes time. The NEC is very strung out, and has to read in steps, so I am not saying I am not missing something. What I will do is I will go to an Electrical Forum I am on and ask those guys if they know of anything else.

First and foremost, the low voltage wire has got to be rated for at least the high voltage in the box. That is code and is found throughout and in the wiring section

Article 725-Classes 1,2,3 Remote Control, Signaling and Power-Limited Circuits
Definitions: Class 1 Circuitry-the portion of the wiring system between the load side of the over current device or power-limited supply and the connected equipment.

725.41A-Class 1 Power limited circuits. These circuits shall be supplied from a source that has a rated output of not more than 30 volts and 1000 volt amperes.
725.48B-Class 1 circuits with Power Supply Circuits. Class1 circuits shall be permitted to be installed with power supply conductors as specified in 725.48B (1-4)

725.48B (1) In a Cable, Enclosure or Raceway. Class 1 circuits shall be permitted to occupy the same cable, enclosure, or raceway only where the equipment powered if functionally associated. (2) In factory or Field Assembled Control Centers.

Sooooo, unless there is another article, which I have 2 more places to reference, what I am reading here is that you can have a low voltage remote control circuit and high voltage circuit in the same junction box. BUT, the last part where it says the equipment powered must be functionally associated will not allow you to have an extra receptable, as I sometimes see. Now if that can be called a control center due to it's listing, then it can power whatever as long as it is doing what it is listed to do.

I will look further and post if I find more. Again, I AM NOT SAYING THIS IS FINAL, BUT THIS IS WHAT THIS PARTICULAR ARTICLE SAYS. The NEC is very complicated to understand and can be interpreted variously. I am sure there is a reason others say that code doesn't allow this, I just have not found it. And it may go back to the t'stat style wire not being rated. Remember, it is key with these mvdc devices that we not have too much resistance, and larger wire will cause more resistance, so I don't know that you can go up to larger wire and still function. If you can, your length will be limited.

There may be something in the definition of what a Field Assembled Control Center can be. I am almost going to go out on a limb and say this is how they are able to make up the box with the additional receptacle, but I am waiting on some counsel from those who know more than I on that one.

[nchvac]

Does the switch fail, or just some wacky stuff w/ the logs?

I have had 2 that for whatever reason started giving large resistance numbers, probably from corrosion or just a weak connection. Any resistance in addition to the wire itself is just about too much for these millivolt circuits to overcome. I was clued in on that by a factory tech a couple years ago. If you jump out at the valve and it works, you need to be looking at your wire and switch to see what the problem is.

Don't throw the switch away due to this resistance. It will work fine on a 120v circuit. Just don't sell it as new stock of course.

[hearthman]

NEC 800.133

exception allows in same gang box if separated by a permanent partition or listed divider which effectively separates them into two boxes. The idea is to keep communications wires at least 1/2" from line voltage.

HTH

[nchvac]

Article 800 is for Communications Systems. This is not communications, it is remote signaling. You have to go to the correct section of the code for it to apply. Communications will be for telephone wire or ethernet, etc.

Example is that conductors can be ran in PVC in damp and wet locations and in metal buildings. But when that metal building is used for Assembly, you have to go to the Assembly section of the Code and find that to use PVC it has to be encased in 2 inches minimum of concrete. It isn't good enough that something is in the code, it has to be for the application.

Frowny Face.