Compact conductors

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olly

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Berthoud, Colorado
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Master Electrician
Correct me if I'm wrong. Most all of wire made these days is considered a compact conductor? Does it list it on the insulation? Ive never seen it. I was told 90% of wire is made to be a compact conductor.
 

iwire

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Correct me if I'm wrong. Most all of wire made these days is considered a compact conductor? Does it list it on the insulation? Ive never seen it. I was told 90% of wire is made to be a compact conductor.

All of the aluminum wire I get is of the compact type.

None of the copper wire I get is compact.

You can tell compact conductors by the shape of the strands, if the individual strands are not round you have a compact conductor.

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jumper

Senior Member
Who told you that?

I thought most conductors were actually just regular stranded and compact conductors would have to be specifically ordered/asked for.

I am pretty sure I have never used them. I have never ordered them nor have seen them speced on my jobs.
 

GoldDigger

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Correct me if I'm wrong. Most all of wire made these days is considered a compact conductor? Does it list it on the insulation? Ive never seen it. I was told 90% of wire is made to be a compact conductor.
In my experience most general purpose wire (excluding service conductors and MV/HV) is neither compact nor even compressed.
I think you will also be more likely to find compact construction in Al wire, since it is softer.
Compact construction makes stranded wire more difficult to bend for the same metal cross section and stranding.

I doubt that compact will be specified on the wire itself; you would have to look at the product specifications.

That said, for service, transmission, and distribution lines compact stranding does seem to be popular. For overhead lines it reduces the wind resistance cross section for the same amount of metal and for cables and insulated wires it also reduces the voltage stress on the insulation surrounding the wire.
 

augie47

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IN an earlier post fmtjfw pointed out the following:


UL White Book 2013 ZKST Thermoset-Insulated Wire and ZLGR Thermoplastic-Insulated Wire:
....
Wire and cable employing compact-stranded copper conductors is so identified directly following the conductor size, wherever it appears (surface, tag, carton or reel), by ??compact copper.?? The abbreviations ??CMPCT?? and ??CU?? may be used for compact and copper, respectively.

Tags, reels and cartons for product employing compact-stranded copper conductors have the marking: ??Terminate with connectors identified for use with compact-stranded copper conductors.??
....

AL wires are also in the same sections.
 

iwire

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Location
Massachusetts
I think you will also be more likely to find compact construction in Al wire, since it is softer.

My understanding is the entire point of making AL compact is so AL conductors of the same ampacity as copper conductors will fit in the same conduit.
 

jumper

Senior Member
Well, what do you know, I've been installing compact AL and never paid attention.

I went to Southwire's site and as Bob said it is compact AL. AA-8000.

Damn, I know I never figured compact wire for conduit sizing. Ooops.:ashamed1:
 

roy g

Member
roy g

roy g

what is the difference between a connector rated for compact conductor and one not rated for compact conductor. how does the affect a connection to a breaker lug
 

mkgrady

Senior Member
Location
Massachusetts
Years ago I had to install mv power cable in an existing duct bank. I went to the customer and informed them that their existing 4" conduits are only 3". We had to get compact strand copper and a special shielded cable (unishield) to make it work.
 

GoldDigger

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Location
Placerville, CA, USA
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Retired PV System Designer
what is the difference between a connector rated for compact conductor and one not rated for compact conductor. how does the affect a connection to a breaker lug

The biggest differences are probably the provision for a smaller diameter and a less rough surface that deforms less easily (compared to normal stranded). Both are closer to the behavior of solid wire. I would guess that a connector rated for solid of the same wire size would do quite well with compact stranded. But:
The most important factor in the listing is probably just that all of the tests were run specifically with compact stranded instead of just normal stranded and/or solid.
 

kwired

Electron manager
Location
NE Nebraska
what is the difference between a connector rated for compact conductor and one not rated for compact conductor. how does the affect a connection to a breaker lug

Not sure if there is any issues with a set screw type lug.

When it comes to crimp on connectors, you need to pay closer attention as they usually will have different size marked for compact vs stranded, and even different values for solid and ACSR as well (if intended for those types).
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
Also as a point to be mentioned. Copper is not compact because it would not be nearly as flexible per it's mass weight. Not all wire manufacturers just produce compact aluminum, some still produce compressed. I can say with 100% certainty that Encore Wire Corporation only produced Compact Aluminum and the Copper is standard.
 

don_resqcapt19

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Staff member
Location
Illinois
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retired electrician
I have installed 15kV copper with compact strands. The customer supplied the cable, 3 conductor jacketed MC listed for direct burial. I think that is the only time I have seen compact stranded copper.
 

mkgrady

Senior Member
Location
Massachusetts
That sounds $$$$.
Yup it was a six figure change order. The cable was something new at the time and made by anaconda. They have since been bought by another company but I can't remember the name. The cable was quite a bit smaller than regular stranded copper shielded mv cable. We installed about 27,000 feet of 15kv cable and it powered an entire us navy yard in cowhampshire ( you know, the one in New Hampshire that is really in Maine)
 
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