Thread: Low Voltage In Stack Vent?

I'm stumped as to why a low voltage wire would be inserted into the stack vent. Is there some kind of sensor or something that is used like this?
a.jpg

did you look on the roof? whats at the other end? Whatever it is , It's wrong

Originally Posted by wayne soper

did you look on the roof? whats at the other end? Whatever it is , It's wrong

Unfortunately, I couldn't see up there. This was an odd house with a very high platform atop a very high and steep roof.
There was a tv antenna up there. There was also an alarm system in the house, so maybe another horn up there.
But it makes no sense to use the vent if it's going up to the roof. They could have just kept it alongside or punched a little hole in the roof.
Doesn't matter too much. I was just curious if anybody has run across some legitimate (but not necessarily right) reason to do this.

Is there some sort of Central Vac system installed in the house?

Originally Posted by James Kollhopp

Is there some sort of Central Vac system installed in the house?

Nope. But interesting question. If there was, what do you think this might have been?

I was going to guess they mounted the antenna to the vent pipe and ran the wire down it, but the wire doesn't look like the antenna wire that I've seen. You said there was a antenna up there, how was it mounted?

I'm not sure of any situation where you can drill a hole in the stack pipe for wires???

Originally Posted by Mike Kleisch

I was going to guess they mounted the antenna to the vent pipe and ran the wire down it, but the wire doesn't look like the antenna wire that I've seen. You said there was a antenna up there, how was it mounted?

I'm not sure of any situation where you can drill a hole in the stack pipe for wires???

Antenna is not on the vent, but a horn could be (again, I couldn't see up there or access it).

The only situation I could conceive of where this might be okay is if there is something that is directly applicable to the vent, like sensing gas or something.

I can't think of why you'd want or need to do anything in there, and if nobody has heard of anything like that, I'm pretty sure this is somebodies misguided idea of getting the wire outside to a horn. Probably not the antenna, since it would have to travel along the flat roof for about five feet and up another two feet of chimney to get to it.

Thanks for pondering with me.

Last time I saw low voltage wires going into a pipe like that, it was associated with the central VAC system. The pipe was different, but it looked similar. It was a rough-in inspection and the system wasnt completely installed, so it had me scratching my head for a minute. Are there any power assisted type vent caps on any of these vents penetrating the roof?

You can't see where either end of the wire terminates?

Originally Posted by Tan Da

I'm stumped as to why a low voltage wire would be inserted into the stack vent. Is there some kind of sensor or something that is used like this?
a.jpg

misguided attempt at supplying electric to the roof. Appears to be standard 16 or 18 AWG stranded cord. Looks like it may be coming from open junction box via plug.

xmas decorating, heat tape to prevent freezing, work on roof etc.

In any event it doesn't belong IN any vent connected to sanitary system. Methane is flamable, noxious, and explosive at low concentrations.

Originally Posted by H.G. Watson, Sr.

misguided attempt at supplying electric to the roof. Appears to be standard 16 or 18 AWG stranded cord. Looks like it may be coming from open junction box via plug.

xmas decorating, heat tape to prevent freezing, work on roof etc.

In any event it doesn't belong IN any vent connected to sanitary system. Methane is flamable, noxious, and explosive at low concentrations.

No, the junction box is not open and has nothing to do with this.
But Yeah, I'm sure the offending cord is for something like that.

The oddest thing to me about this is that it would be much harder to drill a hole in that pipe and go fishing for the wire than to just go direct through the roof or alongside the pipe penetration.
But whatever; People are goofy. Can't say I've never done something and realized later that it wasn't really the best way to do it.

Looks like lamp cord. Are you sure that is low voltage and not line voltage? Regardless, if that is a gas vent or air duct, it cannot be used as shown. Even if this pipe is not being used as a vent or air duct, the penetration and application is unsuitable. Recommend electrician track it down then kill it or grill it.

So, why is this chase open? Looks like you're missing a ton of fireblocking.

Originally Posted by Bob Harper

Looks like lamp cord. Are you sure that is low voltage and not line voltage? Regardless, if that is a gas vent or air duct, it cannot be used as shown. Even if this pipe is not being used as a vent or air duct, the penetration and application is unsuitable. Recommend electrician track it down then kill it or grill it.

So, why is this chase open? Looks like you're missing a ton of fireblocking.

Yeah, it probably was line. It seemed smaller than typical cord gauge at the time, so my mind went to low.

The chase isn't actually open between floors. It was just an odd space with a half wall in it.

Originally Posted by Tan Da

Yeah, it probably was line. It seemed smaller than typical cord gauge at the time, so my mind went to low.

The chase isn't actually open between floors. It was just an odd space with a half wall in it.

Were you able to see where the other end goes (the end going towards the floor)? It appears to be standard Lamp Cord and is not a low-voltage cable, although it may be used for that purpose if it was cheap and easily obtainable.

Two thoughts....

If there are/were antennas on the roof adjacent to this pipe, I would suspect an "easy" way to get power to a RF amplifier connected to the antennas. The question would be, did they leave the power supply in the house and send the low-voltage power on the larger gauge lamp cord, or did they send AC up the stack and have the amplifier and power transformer on the roof. Either way, it not a safe installation.

Or, the wire may come out of the pipe at another location in the house for whatever the purpose.

Originally Posted by Tan Da

I'm stumped as to why a low voltage wire would be inserted into the stack vent. Is there some kind of sensor or something that is used like this?
a.jpg

This practice is used in home theater installation. Connection to the bass output on your amplifier sends reverberation through out the house on all the pipes making for a dramatic experience while watch your favorite movie………or it’s just a hack job extension cord to the roof.
Safely disconnect this wire, remove it, plug the hole and get some fire stop blocking in this chase.
Always interesting and unusual stuff.

It's those green types again... plug the other end of the cord in a socket and burn off all those harmful methane gasses.