wire marking

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K2500

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When a wire is marked "Type MTW or thhn orTHWN-2" what type is it, one the other or all of them? This has me a little confused.
 
Atleast us NC guys say it is. ;)

Afternoon Dennis.

Roger
 
Well, now that I look outside, I guess I should have said evening. :)

You're welcome K2500

Roger
 
K2500 said:
So a wire marked as such plus SUN-RES would be suitable for an OH service drop?
Click to expand...

In most cases (if not all) it would.

Roger
 
I disagree on MTW. I would order MTW for wiring panels and sure enough they would deliver THWN. MTW has a very soft insulation without the thermoplastic outer coating. It is also rated 90c. This type of wire is not intended for pulling in conduit.
It resembles automotive wire in appearance and flexibility.
I have seen some MTW thats looks and feels just like THHN?
I wonder if there are different types of MTW?
 
John Valdes said:
I disagree on MTW. I would order MTW for wiring panels and sure enough they would deliver THWN. MTW has a very soft insulation without the thermoplastic outer coating. It is also rated 90c. This type of wire is not intended for pulling in conduit.
It resembles automotive wire in appearance and flexibility.
I have seen some MTW thats looks and feels just like THHN?
I wonder if there are different types of MTW?
Click to expand...

Just curious, John. What size wire do you use for the control wiring in a panel. I like to use #16, but a lot of places want #14. Given that most of these wires are carrying less than 2 amps. Why do they insist on 14 gauge?:-?
 
John Valdes said:
I disagree on MTW. I would order MTW for wiring panels and sure enough they would deliver THWN. MTW has a very soft insulation without the thermoplastic outer coating. It is also rated 90c. This type of wire is not intended for pulling in conduit.
It resembles automotive wire in appearance and flexibility.
I have seen some MTW thats looks and feels just like THHN?
I wonder if there are different types of MTW?
Click to expand...

John, disagreeing is your prerogative, but a word of advice, don't go making any bets. :wink:

Click Here for Southwires spec.

Roger
 
John Valdes said:
I disagree on MTW. I would order MTW for wiring panels and sure enough they would deliver THWN. MTW has a very soft insulation without the thermoplastic outer coating. It is also rated 90c. This type of wire is not intended for pulling in conduit.
Click to expand...

Where is it stated that MTW cannot be installed in conduit? if that were the case, it would be almost useless to even manufacture it.
 
Well, I learned something new.

I have seen MTW used for things like start/stop stations and remote sensors/flow meters, etc. I guess they must have been in violation. :confused:

I guess THHN/THWN is the only choice for that stuff.
 
Pete I do not think it is exactly prohibited from conduits, what I think is it is application limited.

We could not use MTW for branch circuits but we could use it for control circuits of equipment.

Where I am now we use a lot of it in 16 and 18 AWG....I think I better get the hydraulic wire bender. :D
 
Bob,
We could not use MTW for branch circuits but we could use it for control circuits of equipment.
Click to expand...
Why not? It appears to me that 310.8(A) would permit the use of MTW in any dry location.
310.8 Locations
(A) Dry Locations Insulated conductors and cables used in dry locations shall be any of the types identified in this Code.
Click to expand...
Don
 
don_resqcapt19 said:
Bob,

Why not? It appears to me that 310.8(A) would permit the use of MTW in any dry location.

Don
Click to expand...

Don I am not sure, I am asking.

What do the Application Provisions in T310.13 mean?

It looks to me those provisions limit MTW to wet and dry locations for machine tool wiring.

I also notice that they changed the wording of MTWs Application Provisions from 2002 to 2005.

Bob
 
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