In sci.engr.electrical.compliance Chris Lewis wrote:

| According to :
| In sci.engr.electrical.compliance volts500 wrote:
|
| What about a ceramic conduit? They used to make those a long time ago.
| It was called K&T. So we can just adapt the tubes to be larger, hold a
| whole cable instead of one wire, and run through a duct instead a single
| joist. Maybe glass (not fiberglass) would also work.
|
| Have you ever tried to stretch ceramic conduit? ;-)
|
| I suspect you'd get into trouble with this practise, because the thermal
| insulation value can be quite high. K&T materials simply aren't approved
| anymore.

Why would it need to be stretched? You just drill a hole in each joist
that is the wall of the duct, and slip the conduit across from one to the
other, and fasten it in place so it can't slip out. Now you have a path
through the ductway that is isolated from the duct itself.

This is not a long path. Select a tube wide enough to allow air to flow
through it (between the two ends, not into the duct) with the cable to be
used.

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| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
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