Auxiliary Transfer Switch Contact Kit

This guide explains how the Auxiliary Transfer Switch Contact Kit works and how it compares to dynamic load‑management options like SACM and Load Manager. Use it to decide when a simple “always‑off on generator” lockout is the right choice versus when you need intelligent, multi‑load control.

What the Auxiliary Transfer Switch Contact Kit Does

• The kit (part G005621‑0) is a dry‑contact accessory mounted in the ATS. When the home is on generator power, it opens or closes a low‑voltage control circuit to lock out one specific load (for example, electric heat or a particular HVAC unit). It can also drive a properly rated external contactor to inhibit an entire subpanel. This prevents overloads with a simple, reliable, single‑load lockout strategy.

How This Differs from SACM and Load Manager

• SACM (Integrated Smart Air Conditioning Module): Manages up to four AC units by interrupting their thermostat control wires in priority order. It staggers starts to reduce inrush and sheds/restores AC loads dynamically as generator capacity allows—more than a fixed lockout.
• Load Manager: Coordinates multiple managed loads and automatically sheds a load if it causes an overload. If a managed load trips the generator within 15 seconds, that load is locked out for 30 minutes before a retry; the timer resets when utility returns or the generator is shut down. This is system‑wide, dynamic control rather than a single always‑off lockout.

Where It Fits in Common Installation Approaches

• Partial‑home (circuited) installations: Use the kit to guarantee a known high‑demand load stays off during outages while your selected “essential circuits” remain powered. This provides a simple safety margin without adding dynamic controls. For background on partial vs whole‑home transfer switch placements, see our comparison article.
• Whole‑home installations: If your generator is sized close to your home’s demand, you can combine whole‑home coverage with smart load management (SACM/Load Manager) to keep most loads available, or use the auxiliary kit to hard block a single non‑critical load that would otherwise risk overload.

Choosing Between Options

• Choose the Auxiliary Contact Kit when one specific load should always remain off on generator (for example, electric heat strips or a workshop subpanel). It’s cost‑effective, straightforward, and compatible with both partial‑home and whole‑home ATS installs.
• Choose SACM when you want to keep comfort loads available but intelligently sequenced—ideal for homes with multiple AC units where staggering starts prevents nuisance trips.
• Choose Load Manager when you need priority‑based control across several appliances and automatic shed/restore behavior, including time‑based lockouts after an overload.

Examples

• You have a smaller generator and electric heat strips: use the auxiliary contact kit to disable the heat strips whenever the generator is running, ensuring the rest of the home remains powered.
• You have two or more AC units: use SACM to prioritize and stagger AC operation so cooling remains available without overloading the generator.
• You want whole‑home coverage with a right‑sized generator: use Load Manager to shed lower‑priority loads first and automatically retry them after the lockout period.

Related Resources

• What Is an Auxiliary Transfer Switch Contact Kit?
• What Is an Integrated Smart Air Conditioning Module (SACM)?
• What Is the Difference Between Partial and Whole‑Home Automatic Transfer Switches?
• How long will my load be locked out if it causes an overload when using a SACM or Load Manager?