Stranded Tinned Soft Drawn Copper

[donburde]

I am bidding a job that calls for stranded tinned soft drawn copper and the insulation material called for is THHN/THWN. Anyone ever dealt with this wire? All of my suppliers have been stumped on this one. Could they be implying that I tin the wire ends? I have only seen wire like this in the past for mining and welding applications, never as a thhn or wn. This application is for a marina. Any ideas?

 

[growler]

I am bidding a job that calls for stranded tinned soft drawn copper and the insulation material called for is THHN/THWN. This application is for a marina. Any ideas?

Sounds like something they picked up from boat (ship) builders.

 

[winnie]

Often when I order MTW wire it is tinned. However while THHN/THWN wire is often rated as MTW, not all MTW is rated as THHN.

This company claims to make THHN/THWN with tinned copper wire. I have now idea what the pricing or minimum order would be:
https://www.multicominc.com/product/thhnthwn-2-copper-building-wire/

Good luck!
Jon

 

[GeorgeB]

Bunch tinned

Bunch tinned

MANY years ago, early 1970's, I was an engineering co-op technician at a mobile radio manufacturer. We used bunch tinned cable for in-vehicle runs between components (installed microphone jack, speaker, and remote head). I was not involved with the specification, but our decision makers were convinced it was the most vibration resistant product available. We were told that wiring on marine vessels used it almost exclusively.

It __APPEARED__ to be made of heavily tinned individual strands heated to bond them after twisting. Another term was pre-bonded. I would expect the temperature involved in melding the tin or solder would anneal the copper.

 

[hbiss]

I have some pre-bonded stranded hookup wire here someplace and I can say that its flexibility is somewhere in between solid and stranded. So I can't see where it would be a choice where maximum vibration resistance is needed. We used it because it provided some of the benefits of stranded without having to tin the ends before terminating it when wiring electronic equipment.

I think your spec is for individually tinned strands probably for corrosion resistance.

-Hal

 

[Coppersmith]

That sounds like diesel locomotive cable. The insulation is 90 degree, similar to THHN.

https://www.southwire.com/products/DLODieselLocomotiveCableoem.htm

 

[steve66]

I am bidding a job that calls for stranded tinned soft drawn copper and the insulation material called for is THHN/THWN. Anyone ever dealt with this wire? All of my suppliers have been stumped on this one. Could they be implying that I tin the wire ends? I have only seen wire like this in the past for mining and welding applications, never as a thhn or wn. This application is for a marina. Any ideas?

Sounds a lot like a standard spec paragraph where the engineer has a choice between "tinned" and "untinned". My guess is that they just made the wrong selection.

Or it could possibly be an engineer that doesn't understand the difference.

Tinned (tin coated) conductors are covered by ASTM B33:

https://www.astm.org/Standards/B33.htm

I would ask the engineer for clarification.