Page 1 - Flexible-Stranded-Wire

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Wire Connectors Investigated
for Flexible Stranded Wire
Flexible Stranded Wire
To be UL and NEC compliant while using flexible stranded wire, it was necessary to use crimp-type ring lugs
investigated for flexible stranded wire. By using Marathon’s UL 486A-B investigated screw-type pressure connec-
tors in place of crimp lugs, you can save up to 66% of termination costs in material and labor.
Marathon’s wire approvals, in addition to Classes B
and C, now include stranding Classes G, H, I and
K. The photo shows two distinctly different strand-
ing classes, both 250 kcmil. The wire on the left,
Class B, has 37 strands. The wire on the right,
Class K, has approximately 2499 strands. A table
providing information on wire sizes, Classes and
strand count can be found on the next page.
For specific rating information view our online datasheets at
Screw-type mechanical pressure wire connectors
investigated to UL 486A-B for flexible stranded wire
UL 508A (Industrial Control Panels), Section 29.3.11
Affected Standards:
UL 486A-486B (Wire Connectors Standard)
UL 508A (Industrial Control Panels Standard)
UL 1059 (Terminal Block Standard)
NEC (National Electric Code) 110.3 (A)7 and (B)
NEC 690 (in 2008)
29.3.11 Flexible conductors, including welding cable and machine tool wire identified as “Flexing”
or “Class K”, shall be retained by terminals that have been evaluated to the Standard for Wire
Connectors, UL 486A-486B for the size and type of conductors involved.
Added 29.3.11 effective March 1, 2007
Datasheets available at