Accommodating movement between floors (due to shrinkage settlement) in log homes

[HomeInspectorKenton]

In a situation in which conductors would normally be run between 1st and 2nd floors inside vertical conduit, when a log wall might settle up ro 7 inches over time due to log shrinkage, how can that be accommodated? With plumbing drain and vent pipes, slip joints can be used, but not with conduit because of the potential loss of conductivity. For water supply pipes they use a coil of copper tubing that flexes to accommodate movement. Can a coil of armored cable be used for this purpose? Is there another alternative?

 

[mopowr steve]

In a situation in which conductors would normally be run between 1st and 2nd floors inside vertical conduit, when a log wall might settle up ro 7 inches over time due to log shrinkage, how can that be accommodated? With plumbing drain and vent pipes, slip joints can be used, but not with conduit because of the potential loss of conductivity. For water supply pipes they use a coil of copper tubing that flexes to accommodate movement. Can a coil of armored cable be used for this purpose? Is there another alternative?

If your concerned exclusively about conductivity what makes you think that as an expansion fitting collapses it would loose continuity? I don’t see how en expansion fitting for metal conduit has continuity to begin with without added bonding jumper across it.
Had pvc been used with an expansion coupling this would be a non-issue.

 

[tom baker]

7" is a lot of contraction. Would MC cable work ?

 

[hbiss]

In a situation in which conductors would normally be run between 1st and 2nd floors inside vertical conduit, when a log wall might settle up to 7 inches over time due to log shrinkage, how can that be accommodated?

Simple to solve but unusual problem. If the plumbers used a coil or loop of soft copper tubing there is no reason we couldn't do something similar. The first thing that comes to mind is to put a loop of greenfield at that point. Since this is a conduit run you would pull a ground along with the other conductors.

You certainly could make the whole run MC cable with a loop at that point.

-Hal

 

[winnie]

What is the reason for requiring conduit at that location?

Depending on why conduit is used, cable wiring methods might not be appropriate....or it might make more sense to use a cable wiring method with conduit protective sleeves.

Jon

 

[hillbilly1]

7” is quite a lot, on the ones I wired, the carpenters only allowed for 4-5” for the interior walls and trim. Must be a pretty tall wall. I never run anything in the log wall that was more than two logs deep. Switches are run in a chase in the door trim, never in the logs. If your running emt, plenty of room for expansion joints there.

 

[HomeInspectorKenton]

Yes, 3-4" is plenty for most partition walls and settling spaces over openings.
7" is rare and would be top to bottom of a two story home built with green logs, and they're out there but not many like that. It's a general question, not about a specific home, but we've got about 25,000 members and sooner or later... well, you know the kinds of crazy things you run into over the years! If it's permissible, MC cable is probably what an inspector would hope to find. A slip joint in EMT might be OK if the connection was good enough (right?). The conductor would buck a bit but probably wouldn't damage it.