Question about gas fireplace wiring

[hausdok]

Here's one for the brethren. The issue was discovered by a client who'd been in his new home doing some of his own painting.

When he removed the switch covers from the dual fan/igniter switches on a gas fireplace, in order to paint, he found that only the fan switch was enclosed in box and the other switch, the one that ignites the fireplace, is not inside of a box and is simply secured to the backside of the switchplate and projects into the wall cavity.

When he informed me of this, I looked behind the switchplates on the other two fireplaces and found the identical setup. Now, I don't customarily pulls switchplates, and neither does anyone else here, but can any of your electrical gurus tell me whether this is the way it's supposed to be with gas fireplaces?

The wires on the switches that aren't inside the boxes are 16-gauge or smaller, so I'm assuming that the fireplace ignition system is low-voltage and this has something to do with why these aren't inside the same box as the fan switches.

Can anyone explain?

ONE TEAM - ONE FIGHT!!!

Mike

[charlieb]

IF they are low voltage they are not allowed to be in the same box as line voltage. It can be open to the cavity. Open back "clip on boxes" are available @ the ogange box. Dual boxes are also manufactured. The only ones I've seen in this configuration are nail ons.

[randynavarro]

Originally posted by hausdok

. . . but can any of your electrical gurus tell me whether this is the way it's supposed to be with gas fireplaces?

I'm not a guru but I know this is acceptable.

The wires on the switches that aren't inside the boxes are 16-gauge or smaller, so I'm assuming that the fireplace ignition system is low-voltage

Yes

and this has something to do with why these aren't inside the same box as the fan switches.

Also correct. Low voltage control wires aren't required to be in boxes - think phones, alarm wires etc..

Can anyone explain?

Sounds like you've already figured it out yourself!

(Edited) Thinking about it more, perhaps you're asking how the fireplace ignites using low voltage? A little thermopile is right next to the pilot light. The flame at the thermopile generates enough millivolts to activate the gas valve. When the wall switch is flipped, the contacts are closed and the gas valve opens.

Someone can correct me if I'm mistaken.