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Asco 185SE Auto Transfer Switch (1Ph, 100A)


SKU: 1AUSA2100F4 Category Tag Brand:
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This ASCO Series 185SE Service Entrance Power Transfer Switch automatically transfers single phase loads up to 100A and includes a circuit breaker disconnect device for the normal source. An additional circuit breaker for the emergency source is optional. The automatic transfer switch senses the loss of utility power and signals the generator to start and restore power to your home or business – even if no one is home. When utility power has been restored, the Asco Transfer Switch automatically transfers your vital loads back to the utility and shuts the generator down.


  • User-friendly control interface with easy to understand symbols and visual indicators to inform operator of transfer switch and power source status.
  • Listed to UL 1008 for optional standby systems, handling total system load including motors and all other electrical loads.
  • cUL Listed for Canadian installations.
  • Meets Article 702, NFPA-70 National Electric Code (NEC) requirements.
  • Nominal service voltage 240V 50/60Hz, single phase, 3 wire AC systems.  
  • True double-throw contacts with inherent mechanical interlocking to prevent connection of generator and utility sources.
  • Terminals for convenient connection of neutral and ground conductors.
  • Suitable for controlling standby generators with 2-wire automatic starting circuits
  • Available in NEMA Type 1 Indoor (steel) and Type 3R Outdoor (aluminum) enclosures, with hinged door designs.
  • Textured RAL 7035 light beige color aesthetically suitable for residential applications. 
  • Suitable for use as service entrance equipment.
  • Meets all NEC requirements for service entrance equipment.
  • Circuit Breaker disconnect on the normal source for isolation of transfer switch and other electrical equipment. Optional circuit breaker disconnect on the emergency source is also available.
  • Bonding jumper on Neutral and Ground.
  • Silver plated copper ground and neutral bus.
  • Solderless screw type terminals for External Power Connections.
  • Available with a solid neutral.


Push Buttons

On the front control display are three push buttons that control the operation of the generator and the ATS:

  • Transfer Test: Use this button to test the system. This operation starts the generator and transfers the load. Be sure that conditions are safe to do this operation.
  • Bypass Time Delay: Use this button to cancel the active time delay or exercise period (stops the generator after cooldown).
  • Set Engine Exerciser: Use this button to set the automatic generator exerciser.New/Advanced TSC 9 Series Transfer Controller with features specifically designed for Residential and Light Commercial ATS applications. User programmable timers, Simple LED interface.

Indicator Lights

On the front control display are five lights that indicate the status of the sources and the ATS:

  • Utility Acceptable: This light indicates that the utility voltage is acceptable for connection to the load.
  • Generator Acceptable: This light indicates that the generator voltage is acceptable for connection to the load.
  • Load on Utility: This light indicates that the generator voltage is acceptable for connection to the load.
  • Load on Generator: This light indicates that the generator voltage is acceptable for connection to the load.
  • Automatic Generator Exerciser: When the utility is acceptable and the load is on the utility, this light flashes the number of days until the next exercise period. When it is off, no exerciser period is set. The light is also off when the generator is running.

Time Delays

  • Adjustable 1 or 3 second time delay for overriding momentary utility source disruptions
  • Fixed 4 second time delay while on standby source to ignore momentary generator voltage dips
  • Fixed 5 minute time delay before load retransfer back to utility source, to ensure stability of utility power
  • Adjustable 2 or 5 minute unloaded running time delay allows generator to cool down prior to shutdown
  • Fixed 10 second time delay before load transfer to emergency source, to allow generator warm-up and stabilization


NEMA 1 Indoor

  • Listed to UL 50 standard for electrical equipment enclosures
  • Fabricated from 14 gauge steel
  • Finish – textured RAL 7035 light gray polyester powder coating which is aesthetically conducive for residential applications
  • Doors secured with captive fasteners
  • Conduit knockouts on top/bottom, and both sides

NEMA 3R Outdoor

  • Door over door secure construction
  • Listed to UL 50 standard for electrical equipment enclosures
  • Fabricated from heavy gauge aluminum alloy suited to the size and Ampere rating of the switch
  • Highly corrosion resistant
  • Finish – textured RAL 7035 light gray polyester powder coating
  • Doors secured with captive fasteners
  • Gasket enclosure minimizes ingress of water and dust
  • Internal dead front panel for user safety when accessing controls
  • Conduit knockouts on bottom, and both sides


Asco 185 Brochure

Asco 185 Manual

Asco 185 Warranty

Optional Control Interface (Call to order with transfer switch)

  • Factory installed control interface for Generac Air Cooled Gensets – MUST be ordered with transfer switch.

Optional Field Conversion Kits (See Accessories Tab above to order)

  • Strip Heater Kit with Thermostat for outdoor applications with below freezing temperatures to prevent condensation. Requires external 120V electrical source.
  • Auxiliary Switch Position Contact Kit 14A/14B
Model Number






AIC Rating


Cabinet Type

Service Entrance Rated

Engine Start Contacts

Full Dimensions HxWxD (inches)

Weight (NEMA 1)

Weight (NEMA 3R)



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