Cat Releases Temporary Connection Boxes for Mobile Generator Sets


These facility connection boxes provide an easily accessible docking station to quickly connect a rental generator set to a building’s electrical system, delivering temporary power in a matter of seconds.

Caterpillar has introduced a flexible new family of Cat temporary connection boxes for mobile generator sets.

These facility connection boxes provide an easily accessible docking station to quickly connect a rental generator set to a building’s electrical system, delivering temporary power in a matter of seconds. Typical markets include healthcare, pharmaceutical, industrial, manufacturing, and light commercial construction.

Permanently mounted on the outside of a building, Cat temporary connection boxes feature a NEMA 3R weatherproof, wall-mounted enclosure with a door for cable access. Four configurations are offered to meet a range of needs.

The lug-to-lug tap box is designed for an application in which the end-user’s connections to their distribution system are simply connected via lugs into the box, where mobile generator set cables are quickly landed to a second set of lugs. This configuration supports 200 to 3,000 amps.

An enclosed circuit breaker arrangement is also available for those who don’t have a spare circuit breaker inside their building or are in need of additional circuit isolation for both safety and system protection. Supporting 200 to 800 amps, a circuit breaker disconnect and circuit protection are already built into the box and ready to utilize on a moment’s notice.

Two quick-connect weatherproof camlock configurations are also available with varied ampacity. The wall-mounted camlock tap box supports 400 to 2,400 amps, and the freestanding camlock tap box supports 1,600 to 4,000 amps.

“Understanding where and how to connect to your facility’s emergency power system is an essential component of a well-designed contingency preparedness plan,” said Tom Caldwell, rental power general manager at Caterpillar. “The new Cat temporary connection boxes are designed with ancillary connection options, ensuring that Cat XQ mobile generator sets, which are immediately available through our extensive Cat dealer network and at Cat Rental Stores, can be safely and quickly connected to supply critical power during emergencies or when performing service on existing permanent units.”

Various options suited to meet individual needs can be selected that facilitate ease of use with Cat XQ mobile generator sets. For safety, a phase reversal relay provides visual indication of correct phase rotation. A remote start signal connection is also available so that the temporary generator set can be called on by the facility’s existing transfer switch, and a block heater shore power receptacle includes two 30-amp twist-lock receptacles wired to an internal disconnect to keep the mobile unit pre-warmed and ready for any outage.

“These boxes have been engineered to provide a simple connection for a mobile generator set or load bank, assuring the facility has a solid mechanism for maintaining and testing their permanent assets without interrupting their back-up power capabilities,” said Marc Godwin, switchgear business development manager for Caterpillar. “A prime example are legally required emergency systems that provide power to hospitals and many other locations where reliable electric power is critical to ensure the safety of building occupants.”

These new Cat temporary connection boxes are designed to help facility managers comply with recent updates to the U.S. National Electric Code (NEC) standards for emergency and standby power systems. The NEC requires facilities with an emergency generator set permanently installed in a standby application to provide an alternate source of electrical power in the event that the normal electrical power source is disabled for maintenance or otherwise unavailable.

Cat temporary connection boxes are now available for customers across North and South America. A white paper was recently published about how the Electric Power industry can use connection boxes (docking boxes) for maintenance and is available at

Cat dealers have the ability to provide and install rental generator sets that may be quickly connected via these connection boxes in the event of a non-scheduled service need for the facility’s permanent generator set.