When should we use rectangular versus round cover mounted control units for NEMA contactors and starters?

Issue:
When selecting a cover mounted control unit (such as HOAs, pilot lights, and push buttons) for NEMA contactors and starters when should we use square/rectangular control units and when should we use round control units

Product Line:
NEMA Contactors and Starters

Environment:
All NEMA Contactors and Starters

Cause:
Selecting the correct cover mounted control unit for NEMA Contactors and starters.

Resolution:
Square/rectangular mounted control units are for use in the pre-series K NEMA type 1 enclosed starters and contactors. Series K and later NEMA type 1, 3R, 4, 4X, and 12 use the round operators. Series K was introduced in 11/2010.

9999SP28R, 9999SP2R, 9999SP3R, 9999SP4R, 9999SP5R, 9999SP12R, 9999SP13R, 9999SP14R, 0000SP15R, 9999SA2, 9999SA3, 9999SA10, 9999SC2, 9999SC8, 9999SC9, 9999SPL28R, 9999SPL28G, 9999SP29R, 9999SPL29R, 9999SPL29G