What’s the proper (if there is one) way to run new wiring from a basement to a second floor through a vent shaft? This home was built in 1926 and has a shaft running behind the kitchen wall that contains two large vents that are no longer in use. It’s just dead space. I’m sure the wire can’t be left “dangling” in mid-air (secured at the top and bottom of the run, with the wiring between those points unsecured to anything within the shaft)- but securing it to the framing inside the shaft is difficult because there’s no access unless the walls are opened up, and the homeowner really doesn’t want to do this.
Thanks for any help on this.
Steve
Replies
Well, if the vent shaft serves any venting purpose at all it's likely to be interpreted as a plenum and only plenum-rated wiring is allowed. In any event, for safety's sake (and to guarantee that it won't be interpreted as a plenum), the shaft should have draft stops installed at intervals.
If the space is really not used as a vent, then nothing applies -- you get a free ride.
As for support: there is an exemption in the Code that absoves thee of fastening or support requirements when fishing in enclosed walls.
~Peter
Thanks for the information. Is not having draft stops a major risk? This is a fairly large vent shaft- about a 3.5 ft by 3.5 ft- with two 12 inch vents inside, which are cut off at the attic and basement. It would be much easier not to open up walls to secure the new wiring inside the shaft, or install draft stops, but I'm looking to advise the homeowner on the proper way to do this. I appreciate the feedback.Steve
pm22 is right. Free reign on the fishing in walls unsecured.
Ask a building inspector about your specific case regarding the draft stop. You coud ask him "theoretically speaking" if nessecary.
A little drywall or plywood and some fire caulk would probably do the trick.
Or, if you want the space for a future service chase, several companies make removable firestop pillows. They are like sponge bricks in plastic bags that you just stuff in the opening. You can pull them out, pull something through the space and stuff them back in...over and over. If there is a fire, they expand and stop any draft from helping the fire spread.If you haven't drawn blood today, you haven't done anything.