Trimming wire

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nizak

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Is it a code violation to trim strands of wire in order to fit into a lug?

I have two 300 KC Mil neutrals that I need to get into a 250 max lug.

Thanks
 
I would say yes but I'm not sure where you can actually find specific wording that prohibits it. The obvious question is that once you remove some strands how do you know how much you've lowered the ampacity of the conductor.
 
I agree with Rob. You can either change the lugs or use reducers like below

1724070901780.png
 
Does the smaller end of reducer also lower ampacity?
 
kec said:
Does the smaller end of reducer also lower ampacity?
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According to these instructions no it does not.

1.NOTES:
TIN PLATED ALUMINUM COMPRESSION PIN ADAPTER.
2.
CONNECTION: COMPRESSION CONNECTIONS ARE MADE IRREVERSIBLE AND MAINTENANCE FREE.
3.
APPLICABLE STANDARDS: CONNECTORS ARE ONLY UL LISTED AND CSA CERTIFIED WHEN INSTALLED WITH THE BURNDY ENGINEERED SYSTEM AND SELECT OTHER CRIMP TOOL MANUFACTURERS IN ACCORDANCE WITH ONE OR MORE UL
CATEGORIES. UL LISTED AND CSA CERTIFIED WIRE-CONNECTOR ADAPTERS. TESTED IN ACCORDANCE TO UL 486A-486B / CSA C22,2 NO.65
4. TEMPERATURE AND VOLTAGE RATING:
A. UP TO 35kV WITHOUT COVER. CONNECTORS ARE MARKED AL9CU TO DENOTE ALUMIUM(AL) OR COPPER (CU) WIRE UP TO 90°C.
B. ONE COVER SUPPLIED WITH THE CONNECTOR.
C. RATED 600 VOLT UP TO 90°C.
D. MADE FROM THE FOLLOWING MATERIALS: EPDM RUBBER, SANTOPRENE, OR PVC.
5. WIRE ACCOMMODATE TYPES (SEE TABLE): DUAL RATED TO ACCOMMODATE ALUMINUM AND COPPER WIRE.
A. ALUMINUM WIRE (AL): CLASS B (CONCENTRIC, COMPRESSED, COMPACT)
B. COPPER WIRE (CU): CLASS B (CONCENTRIC, COMPRESSED, COMPACT) OR CLASS C.
C. COPPER FLEX (CU): SEE TABLE FOR APPLICABLE WIRE CLASSES.
6. FEATURES:
A. SOLID PIN DESIGN ELIMINATES “HOW TIGHT IS TIGHT” TORQUE REQUIREMENT PROBLEM AND ELIMINATES OVER TORQUING ON STRANDED PIN ADAPTERS THAT COULD DAMAGE THE PIN AND CONNECTION.
B. SOLID PIN IS RATED FOR THE FULL AMPACITY OF THE INCOMING CONDUCTOR.
C. INLINE AND OFFSET PIN DESIGNS ARE AVAILABLE. OFFSET PIN DESIGN PROVIDES ADDED FLEXIBILITY IN LIMITED SPACE APPLICATIONS AS THE CONNECTORS CAN BE ROTATED.
D. BARREL TYPICAL ROLL MARKINGS (AS SPACE PERMITS): CRIMP ZONE IS INDICATD BY KNURL BANDS, BURNDY CORPORATE NAME OR LOGO, UL LOG (IF APPLICABLE), CSA LOGO (IF APPLICABLE), WIRE SIZE, DIE COLOR CODE, INDEX NUMBER.
E. BARREL DESIGN: BARREL END AT THE WIRE HAS AN INTERNAL FLARE, ALLOWING FOR SMOOTH WIRE INSERTION.
F. PRE-FILLED WITH PENETROX™A13, WHICH IS AN OXIDE INHIBITOR.
G.COLOR-CODED END CAPS TO MATCH THE DIE COLOR CODE. THIS ALSO PREVENTS PARTICLES FROM ENTERING THE BARREL.
7. INSTALLATION TOOLING AND DIES ARE CONSTANTLY BEING UPDATED. FOR THE LATEST INSTALLATION TOOLING INFORMATION, REFER TO THE MASTER CATALOG ON THE BURNDY WEBSITE.
8. DIMENSIONS IN BRACKETS [ ] ARE IN MILLIMETERS ROUNDED OFF TO THE NEAREST MILLIMETER, UNLESS OTHER SPECIFIED AND ARE FOR REFERENCE ONLY.
9. FOR PROPER INSTALLATION INSTRUCTIONS, SEE PRODUCT INSTALLATION GUIDE ON THE LAST SHEET.
10 NOT UL LISTED OR CSA CERTIFIED WITH THESE DIES.
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kec said:
Does the smaller end of reducer also lower ampacity?
Click to expand...
infinity said:
I would say yes but I'm not sure where you can actually find specific wording that prohibits it. The obvious question is that once you remove some strands how do you know how much you've lowered the ampacity of the conductor.
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Would dividing the number of strands by the ampacity give a relatively accurate value of what each strand carries?

I know it’s sounds rudimentary but in a pinch it could provide a close number.
 
nizak said:
Would dividing the number of strands by the ampacity give a relatively accurate value of what each strand carries?

I know it’s sounds rudimentary but in a pinch it could provide a close number.
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If you only removed enough strands so that it fit tightly into the terminal before tightening it would work for 100 years without issue.
 
nizak said:
What rating would You be referring to?
Size?
Torque?
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The problem I have with the solid pin adapters is that most larger terminations are only listed for use with Class B or C stranded conductors. There is at least on manufacture of pin adapters that uses a stranded conductor for the pin.
 
nizak said:
Is it a code violation to trim strands of wire in order to fit into a lug?

I have two 300 KC Mil neutrals that I need to get into a 250 max lug.

Thanks
Click to expand...
disregarding listing one could be using the 300K for voltage drop reasons and the actual load may be less than ampacity of a 250K conductor which possibly would never introduce any significant heating of said connection. But is there any recognized way of determining what is acceptable here? Does any lug manufacturer or conductor manufacturer tell us how the ampacity of the termination is to be adjusted when removing strands? NEC certainly does not have any information on how to do this. An inspector would have to default to making you follow any instructions that come with listings and there really is nothing that addresses this that I know of. A pin connector would be limited to anything covered in its listing.

Pin connectors likely are intended to mostly be used for situations of oversized conductor for voltage drop reasons where the load would typically be no more than the smaller sized lug is designed for.
 
I had to do it not long ago. 100amp service on a Saturday and SH left material in a room for pick up Friday night.

They gave me 4/0 aluminum when I only asked for #2awg aluminum.
 
This is from a PDF for the 2017 NEC. I no longer have access to more current PDF copies of the NEC. I believe that this article would not allow the conductor strands to be cut. It is article 110.14 A

(A) Terminals. Connection of conductors to terminal parts shall ensure a thoroughly good connection without damaging the conductors and shall be made by means of pressure connectors (including set-screw type), solder lugs, or splices to flexible leads. Connection by means of wire-binding screws or studs and nuts that have upturned lugs or the equivalent shall be permitted for 10 AWG or smaller conductors. Terminals for more than one conductor and terminals used to connect aluminum shall be so identified.

Thanks, Bill
 
Honestly I dont see what the issue is, as long as you keep the remaining strands so they fit snugly in the lug, and your OCPD is not more than the ampacity computed from a size or two down from the max the lug can take. With Aluminum conductors in particular, it could be done very neatly and with no question. IF you run your sawzall or bandsaw around an aluminum conductor about 2/3 of the way through the outer ring of strands, you can then bend them back and forth and they will break off very neatly and cleanly. Then, because it is a compact conductor, you can measure what remains if you have a set of dial calipers to confirm that what is left as sufficient ampacity. Might be a deal breaker if a ring removal left a conductor that was too large to fit, but removing the next ring would not have enough ampacity.
 
electrofelon said:
Honestly I dont see what the issue is, as long as you keep the remaining strands so they fit snugly in the lug, and your OCPD is not more than the ampacity computed from a size or two down from the max the lug can take. With Aluminum conductors in particular, it could be done very neatly and with no question. IF you run your sawzall or bandsaw around an aluminum conductor about 2/3 of the way through the outer ring of strands, you can then bend them back and forth and they will break off very neatly and cleanly. Then, because it is a compact conductor, you can measure what remains if you have a set of dial calipers to confirm that what is left as sufficient ampacity. Might be a deal breaker if a ring removal left a conductor that was too large to fit, but removing the next ring would not have enough ampacity.
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It maybe works in theory, yet no real studies by the correct agencies to allow acceptance of that method either.
 
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