Class C Connectors

[Dennis Alwon]

I was at the state meeting in Raleigh this week and Jeff Fecteau from UL was on the board answering questions. He stated that the standard red and yellow wirenuts weren't listed for Class C wire. If you go to Chapter 9 Table 10 you will see that #12 wire has 7 strands and is rated Class B. However rubber cord such as SJO and the like is rated Class C with 19 strands. This means that you cannot connect the wires in sjo cord with the standard wirenuts. I included the link to UL-- do you all read it the same way?

Here is what I found in UL book

Stranded conductor Class — Connectors rated for use with stranded conductors are for the following strand configurations:
Aluminum – Class B concentric, compressed or compact, and SIW (.single input wire)
Copper-clad aluminum – Class B concentric or compressed, and Class C concentric
Copper – Class B concentric or compressed, and Class C concentric Wire connectors additionally rated for use with compact copper conductors are additionally marked ‘‘For compact-stranded copper conductors’’ or equivalent on the connector, or on or within the unit container.

 

[Smart $]

... I included the link to UL-- do you all read it the same way?

Here is what I found in UL book

Link???

I read what you quoted as permitting Class C...???

 

[Dennis Alwon]

Link???

I read what you quoted as permitting Class C...???

I read it as stating it is permitted if it is marked which most are not.

What do you want a link to....

 

[jumper]

What do you want a link to....

IDK, I downloaded the 2012.

http://www.ul.com/global/eng/pages/offerings/perspectives/regulator/electrical/newsletters/

 

[Dennis Alwon]

Oh yeah the white book is available as a free download but I posted the part that was pertaining to the thread

 

[joebell]

Dennis,

Are flexible cords consiered compact stranded or bunch stranded? According to the information I found in The Electricians Handbook it looks as if flexible cords fall under bunch stranded and places it as class K or M. I've been trying to figure out exactly where flexible cord falls in terms of class since the change occurred in 110.14.

 

[Dennis Alwon]

Dennis,

Are flexible cords consiered compact stranded or bunch stranded? According to the information I found in The Electricians Handbook it looks as if flexible cords fall under bunch stranded and places it as class K or M. I've been trying to figure out exactly where flexible cord falls in terms of class since the change occurred in 110.14.

This stuff is confusing to me. If you look at the table you will see that rubber cord clearly has more than 7 strands which would put it in a class C minimum. It may be greater but even so the wire nuts according to Jeff are not listed. I have never seen one fail nor do I expect anyone to do anything differently. I just thought that this was interesting.

I have seen rubber cord terminated on lugs that I am certain were not listed for it.

 

[Dennis Alwon]

Class K for #12 wire must have 65 strands. That would not surprise me that rubber cord has that many strands. That IMO makes it worse.....

Here is a good link for a wire chart for the class of wires

 

[joebell]

This stuff is confusing to me. If you look at the table you will see that rubber cord clearly has more than 7 strands which would put it in a class C minimum. It may be greater but even so the wire nuts according to Jeff are not listed. I have never seen one fail nor do I expect anyone to do anything differently. I just thought that this was interesting.

I have seen rubber cord terminated on lugs that I am certain were not listed for it.

I agree completely, I attended an IAEI event 3 years ago when Fred Hartwell discussed this very same topic in regards to the change associated in 110.14. If flexible cords are classed other than class B or C how does this affect terminations to connector bodies or receptacles as well as lugs and wire connectors.

 

[MarineTech]

Class K for #12 wire must have 65 strands. That would not surprise me that rubber cord has that many strands. That IMO makes it worse.....

Here is a good link for a wire chart for the class of wires

Dennis thanks for the link. Here is another for type K.

http://www.cobrawire.com/x-flex/x-flex.php

For Marine we use UL-1426 as a base, and then add tinning and high stranding like Type K for flexibility. For example:

http://wire.almo.com/Products/mar_ul1426.asp

The primary approach for me, in using the high stranded K cable, termination is done with crimp lugs. The type of crimp (Tool) depends on the lug manufacturer (per wire diameter) and recommended pressure and approach.

 

[Dennis Alwon]

Here is an email I got from Jeff Fecteau

First look at 2011 NEC section 110.14;
Connectors and terminals for conductors more finely stranded than Class B and Class C stranding as shown in Chapter 9, Table 10, shall be identified for the specific conductor class or classes.

If the conductor has stranding then that identified in Chapter 9, Table 10 then it is not a Class B or Class C conductor:

Here he posted the table from Chapter 9 that I mentioned



Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

Now look at UL Product Category ZMVV (Wire Connectors and Soldering Lugs);
http://database.ul.com/cgi-bin/XYV/...n=versionless&parent_id=1073996457&sequence=1

Stranded conductor Class ? Connectors rated for use with stranded conductors are for the following strand configurations:

Aluminum - Class B concentric, compressed or compact, and SIW (single input wire)
Copper-clad aluminum - Class B concentric or compressed, and Class C concentric
Copper - Class B concentric or compressed, and Class C concentric
Wire connectors additionally rated for use with compact copper conductors are additionally marked "For compact-stranded copper conductors" or equivalent on the connector, or on or within the unit container.

Wire connectors additionally rated for use with other Class conductors, such as Class M, are marked with the additional class designation and number of strands.

Here is a table that identifies conductor Classes and the number of strands for each Class conductor, any wire connector other than Class B or Class C is required by ZMVV and UL 486A - 486B to be marked for the conductor Class and number of strands;


Here he posted the link to the chart I posted