Traditionally, bare wire terminals used on Power Blocks and Fuse Holders have only been evaluated for use with rigid (Class B & C) wire. The majority of MSP’s terminals have been evaluated for use with flexible stranded wire classes such as Class G, H, I (DLO) and K per UL 486A-B. This enables customers to be UL and NEC compliant while using flexible classes of wire without the use of crimp type terminals. We also supply a range of studded products to allow for the use of crimp terminals, which are recommended for larger wire sizes (greater than #1 AWG).
Flexible stranded wire classes also bring additional considerations to address such as an increase in wire diameter and the number of strands per a given wire size. The photo to the right shows two 250 kcmil wires of different classes. The one on the left is the traditional Class B with 37 strands. The one on the right is a finely stranded Class K. Although they are the same wire classification of 250, you can see the Class K is larger in diameter. This illustrates the need to specify a terminal to accept a larger standard wire size. The table below shows the increase in strand count per each wire size.