Med. Voltage Switchgear C37.20.2-Wire sizing

[DGrant041]

I am having a problem finding a wire I can use in UL listed switchgear AND will fit onto an AB SLC 500/5000 series PLC. UL does not have a standard for Listing Medium Voltage Switchgear so they differ to ANSI/IEEE C37.20.2.

7.3.3.2 Wire size
Wire must be suitable for the anticipated maximum steady-state load. The size chosen also must accommodate voltage drop within the switchgear, including the effect of intermittent heavy loads (shunt trip coils, inrush from relays, and the like). The following criteria shall be used as minimums:

EXCEPTION: Multiple-conductor cable (two or more insulated wires inside a common insulated jacket) used in logic-level and/or supervisory circuits may use wire sized as required by the circuit.

We've been using 20 AWG wire on the doors for indicating lights and PLC's for many years. UL and ANSI/IEEE say minimum of 18 ga. That would be fine but we can't seem to fit that into AB SLC 500/5000 PLC's that have the vertical style cards or into lugs that would normally accept (2) 20AWG.

Does anyone know a solution to this problem? (ie A wire type smaller than SIS to fit into the lugs & PLC.) UL has been NO help despite many alternative recommendations from us.