Square D 9999SO5 Contactor Auxiliary Contact

Product Description

The SQUARE D 9999SO5 is a contactor auxiliary contact designed for use with overload relay assemblies in motor control and load switching applications. Auxiliary contacts expand the signal and control circuit capability of a contactor without interfering with the main power contacts. This accessory mounts directly to compatible contactor or overload relay bodies, giving control panels an additional monitored contact point for interlocking, status indication, or circuit logic. Electricians and control panel technicians typically install this part as part of a motor starter build or a panel retrofit. The compact form factor keeps installation straightforward in tight enclosures.

This auxiliary contact is suited for commercial and industrial motor control installations where contractors require supplementary contact blocks on overload relay assemblies. Common applications include motor starters, reversing contactors, and combination starter assemblies found in mechanical rooms, pump stations, and industrial process panels. It is installed during new panel builds or as a replacement contact block when an existing auxiliary contact fails or is damaged during service.

Key Features

• Auxiliary contact configuration adds supplementary control circuit contact points to compatible overload relay assemblies
• Compact dimensions of 3.1 inches length by 2.3 inches width by 1.4 inches height allow installation in tight enclosure layouts
• Lightweight construction at 0.1 pounds minimizes added load to the contactor assembly
• Direct-mount accessory design integrates with the contactor or overload relay body without additional hardware
• Packaged as a single unit for precise replacement or single-position panel builds

Compatibility

Designed as an OEM-style replacement auxiliary contact for use with overload relay assemblies in compatible contactor configurations.

Installation Notes

Installation should be performed by a licensed electrician. De-energize and lock out the control panel per NFPA 70E and NEC guidelines before handling any contactor or relay components. The auxiliary contact block snaps or bolts onto the contactor or overload relay body according to the assembly design — consult the specific contactor manufacturer documentation for mounting orientation and attachment method. Verify contact alignment and secure attachment before re-energizing the panel.