Wire for Control Panels

[TwoBlocked]

You guys that do panel work know how nice some MTW/TFFN is that will lay wherever is is placed, but other MTW/TFFN wire is better than THHN but is still tough to manage. I've notice the nice stuff usually has silver colored markings on it, but besides that, I haven't noticed it as a specific "type" listed on the labelling. Is it brand name thing or what?

So how do I ask for "The Right Stuff"?

 

[Jraef]

MTW (machine tool wire) just describes the insulation type and voltage rating. The difference in workability has to do with the strand count. Basic cheapest MTW has 19 strands, the stuff that is easier to use can have upward of 168 strands. The higher the strand count, the more expensive the wire is for the same gauge.

The problem is, the high strand count may require the use of special lugs and terminals. Wire standing comes in "Classes", B through M. Class B is typically 7-9 strands, Class C is the 19 strand stuff and as far as I know, all lugs and terminals are OK for using Class B and C. But once you go to Class D or higher, that's where you find out that the lugs and terminals are not listed for that, so you need to buy special. So you may have used some Class G stranded MTW and unknowingly connected it to lugs and terminals that were not rated / listed for that.

 

[TwoBlocked]

But it seems the insulation on the not-so-good is shinier than the really-good stuff.

 

[LarryFine]

Maybe unroll several feet and pull it straight first.

 

[Todd0x1]

But it seems the insulation on the not-so-good is shinier than the really-good stuff.

is your not shiny stuff mtw/tff with no nylon outer jacket?

 

[TwoBlocked]

Maybe unroll several feet and pull it straight first.

It helps, but it's not the same.

 

[TwoBlocked]

is your not shiny stuff mtw/tff with no nylon outer jacket?

The somewhat shiny stuff has no nylon out jacket, either. I'll have to look more careful on the markings to see what the strand count is, like Jref says. That's probably the difference.