I'm doing some work in my (unfinished, never going to be finished) basement. I have to run some new wiring about 2 feet across a concrete block wall. There is one 6-3 cable and 4 12-3 cables. Is it permissible to fasten the 6-3 cable to the wall and then tie-wrap the other cables to it? If not, can I screw anchors into the wall and tie wrap the whole bundle to the anchors?
Is there a better way to do this?
Thanks.
I don't believe the Nec allows bundling cables, although I can't find anything that specifically says this. You certainly can use tie wraps, but it may be easier to screw a slice of plywood to the wall then staple them to it, individually.
Might do it neatly...plastic junction box #1 mounted on concrete with cables input to it. Plastic conduit(s) to junction box #2 mounted on wall. Regular wire coupling the two together. No code problems, no appearance problem (inspectors can be real twits sometimes) and quickly done. The downside, a few buck$ more than a pine board or some such.
Joe
In article , snipped-for-privacy@aol.com (Joe) writes: | On Aug 5, 5:58=A0pm, rangerssuck wrote: | > I'm doing some work in my (unfinished, never going to be finished) | > basement. I have to run some new wiring about 2 feet across a concrete | > block wall. There is one 6-3 cable and 4 12-3 cables. Is it | > permissible to fasten the 6-3 cable to the wall and then tie-wrap the | > other cables to it? If not, can I screw anchors into the wall and tie | > wrap the whole bundle to the anchors? | >
| > Is there a better way to do this? | >
| > Thanks. | | Might do it neatly...plastic junction box #1 mounted on concrete with | cables input to it. Plastic conduit(s) to junction box #2 mounted on | wall. Regular wire coupling the two together. No code problems, no | appearance problem (inspectors can be real twits sometimes) and | quickly done. The downside, a few buck$ more than a pine board or some | such.
Does surface-mount PVC conduit like this have to be schedule 80?
Dan Lanciani ddl@danlan.*com
Of course your local electrical inspector is the final word on this... But electric wires are "happier" when air can circulate around them. If they are tightly bundled, they can build up heat and this can be dangerous. So better if loose in a conduit or run separate...
If these are bundled or put in a conduit, you will have to derate the ampacity. Even with 90c conductors, you can't bundle more than 3 of those 12-3s without derating. The #6 gets into trouble even quicker but at 6 conductors you are still OK for 60a breaker in most applications. The answer would be make 2 bundles. (three 12-3s and a 12-3 with the
6-3).The other issue is you can't support one wiring method with another so put your tywraps around the whole bundle and fasten that to the wall. They do make pads you screw to the wall and then you loop the tywrap through slots on the pad.
I don't have time to dig through my code book, but are the cables even required to be supported on the block wall at all if it is only a 2' span and they are supported on either side of the wall?
I can't picture what his situation is, but no, the cables have to be supported at 4.5' intervals, so if they're supported on either side, they wouldn't have to be supported on the block
two feet? Let 'er hang.
..
OK, That's good news. Doing the two boxes and pipe thing is a bit much, I think, especially since the wires have to go on a wall behind a soil stack that only has, maybe an inch and a half clearance from the wall. So, there wouldn't be room for a decent sized conduit. Also, these would have to be pretty sizeable boxes to hold all those splices.
The exact situation is: The cables come down from a wall above, over the sill plate. Then they run along the block wall, behind the soil stack to a (perpendicular) joist. They follow that joist for a couple of feet (to clear other wiring and a shelving unit), and then through a hole in that joist (and 8 other joists) to the panel. I can anchor them a couple of inches to either side of the stack. It's not the prettiest, but it's not a pretty space to begin with.
OK, That's good news. Doing the two boxes and pipe thing is a bit much, I think, especially since the wires have to go on a wall behind a soil stack that only has, maybe an inch and a half clearance from the wall. So, there wouldn't be room for a decent sized conduit. Also, these would have to be pretty sizeable boxes to hold all those splices.
You would NEVER install boxes, and have a pile of splices unless it was absolutely necessary. What you can't do is support a cable from another cable, but you can certainly do as gfretwell describes, and collect a few cables together and strap them, and again, the cables need to be supported every 4.5' and within
12" at boxes.The exact situation is: The cables come down from a wall above, over the sill plate. Then they run along the block wall, behind the soil stack to a (perpendicular) joist. They follow that joist for a couple of feet (to clear other wiring and a shelving unit), and then through a hole in that joist (and 8 other joists) to the panel. I can anchor them a couple of inches to either side of the stack. It's not the prettiest, but it's not a pretty space to begin with.
Just a followup - I screwed a hunk of plywood (about 6" x 30") to the wall, just below the sill plate, and stapled the 12-3 cables and anchored the 6-3. I does look neater this way, and wasn't a very big deal.
Thanks, folks.
Excellent solution
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