We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in
Copper two-hole compression lug, long barrel, brown colour code, straight tongue 1.53 in wide, 1.75 in hole centres

3M

3M 31166 Two-Hole Compression Lug 500 kcmil 1/2 in Stud Long Barrel

SKU CH-CV5Y-8FPKN

A two-hole compression lug for 500 kcmil copper wire with a 1/2 in stud and long barrel

  • TypeElectrical Connectors
  • Rated for 35 kV maximum voltage
  • Seamless copper barrel resists cracking
  • Two-hole NEMA spacing at 1.75 in centres
  • UL Listed and CSA Certified for code compliance
  • Long barrel design accepts 500 kcmil copper conductor

500 kcmil Copper Compression Lug

The 3M 31166 is a two-hole copper compression lug rated for stranded copper conductors up to 500 kcmil. It accepts a 1/2 inch stud and features a long barrel design for extended crimp engagement. The lug is UL Listed and CSA Certified for use up to 35 kV maximum voltage. Brown color coding and die code 20 identify the correct installation tooling.

Long Barrel Seamless Crimp Performance

A seamless barrel construction eliminates a potential split path during high-compression crimping. The long barrel provides additional surface contact between the connector and conductor strands. This geometry distributes mechanical stress evenly across the crimp zone under sustained electrical and thermal loading. Copper material ensures consistent conductivity throughout the connection lifecycle.

Two-Hole Mounting Constraints

Hole centres are fixed at 1.75 inches apart, dictating the compatible busbar or terminal pad drilling pattern. The tongue width measures 1.53 inches and sits at a straight angle relative to the barrel axis. Barrel inside diameter is .83 inches and outside diameter is 1.06 inches, defining the conductor fit and insulation clearance envelope. No inspection hole is present on this model.

Highlights

  • Rated for 35 kV maximum voltage
  • Seamless copper barrel resists cracking
  • Two-hole NEMA spacing at 1.75 in centres
  • UL Listed and CSA Certified for code compliance
  • Long barrel design accepts 500 kcmil copper conductor

Specifications

Brand3M
TypeElectrical Connectors

Questions about this item

How much heat does the 31166 lug generate when carrying 500 kcmil current all day?

The copper lug itself produces negligible heat; temperature rise depends on the crimp quality and the conductor's ampacity, not on the lug alone.

What crimp tool and die are required to install the 31166 lug on 500 kcmil copper wire?

Use a hydraulic crimper with a die coded 20 (brown colour code) to achieve the UL-listed, CSA-certified connection.

Will the 31166 lug fit on the same 1/2 in stud spacing as my existing 1.75 in centre-to-centre bus bar?

Yes, the lug has two holes on 1.75 in centres for a 1/2 in stud, matching that standard bus-bar pattern.

Also in this aisle

People compared these

Same shelf, same checkout — eight coins and a 30-minute rate lock.