more flexible wire

[winnie]

Again: The OP doesn't really need 'more flexible' wire. What is needed is wire insulation that has better high temperature survival.

This wire is being used between the junction box (pecker head) and some other part of the system, so it needs to be one of the wire types considered suitable for use in a raceway; neither MTW nor DLO cable is listed for that application (however the cable might have multiple ratings; for example you can buy MTW wire that also has a THHN rating, and is thus suitable for either application).

Finally, Don's question about the temperature in the junction box is a good one. It may be that there is a design issue such that the JB is too hot...or it may be that the JB is simply near the peak allowed temperature. Since conductors are rarely applied near their peak temperatures, we are often surprised at the amount of insulation degradation when they are used in this fashion.

-Jon

 

[guschash]

We used fiberglass insulation, in the glass plant I worked at. Pretty flexible and did not crack.

 

[Doug S.]

Again: The OP doesn't really need 'more flexible' wire. What is needed is wire insulation that has better high temperature survival.

FIRST, I am not picking on you Jon, however, you bring up a point of interest for me.

I have through the few years of my profession ran in to many THHN junctions were insulation breakdown has occurred (the stuff just crumbles off) and I am fairly certain it has NOT reached 90?c. (#12 feeding a fractional hp mtr, no copper discoloration, and the like) I am fortunate enough to be an on-site guy, so you "get to know" your equipment, and the previous statement is not just a loose observation, nor is it proof, but a theory based on experience. The opp seems to be experiencing something I think many of us have seen. The insulation only becomes brittle at tight radius bends, and near the junction, hence leading myself and others to believe the wire is not the correct wire for the app, based on the fact it's packed into a pecker-head.

Am I nuts? ( Yes I know the pecker-head can experience higher temps... )

Curious,
Doug S.

 

[dreamsville]

Doug's experienced my conundrum

Doug's experienced my conundrum

Doug, you hit it right on the head. Thank you.
Since this thread has started I've replaced the offending THHN wire with XHHW-2. It has a rubber insulation and I believe it will hold up better to the application.