Out of dozens of docking station arrangements, which one is best?
Portable generator docking stations may be specified in many different arrangements, each ideally tailored to the specifics of a given project. After reviewing hundreds of applications, and a few dozen docking station designs, one specific configuration looks to me as the “best all-around” solution for most projects.
While looking at the pros and cons of various docking station designs, I considered operator’s safety, value to owner, ease of operations, and emergency power availability. Here is the configuration that checked off all of the boxes for me.
The Foxfab Dual-Breaker Dual-Purpose Docking Station in Configuration #504
The Foxfab FFCC-C3 (wall-mount) and FFCC–P2 (pad-mount) dual-breaker dual-purpose docking stations, when designed as Configuration #504, offer a combination of features that simplify generator interlock operations, enhance serviceability, and minimize power disruptions during generator testing. In this article, I will describe the technical and operational advantages of these docking stations, and how Specified.Works can support clients in the design, specification and delivery of this solution.
At its core, the Foxfab dual-breaker dual-purpose docking station are designed to provide safe transfer from a permanent emergency power source to a portable generator power source, and to allow connection of a load bank for testing of the permanent generator.
It is important to note that a dual-breaker dual-purpose docking station can be designed in a few different ways. The electrical position of the circuit breakers, and the points of connection for the permanent generator, for the portable generator, and for the load bank, can vary between designs. My preferred arrangement is identified by Foxfab as Configuration #504, as shown on this one-line diagram:
This specific dual-breaker dual-purpose design includes these key features:
- Dual-Breaker Configuration: The docking station is equipped with two circuit breakers—one for the permanent generator and one for the portable generator. This configuration allows safe switching between power sources, all from one physical location, right at the docking station.
- Interlock Mechanism: The Kirk Key interlock mechanism ensures that only one breaker can be closed at a time, ensuring safety and NEC-compliant operation.
- Load Bank Connection: The dual-purpose nature of Foxfab’s Configuration #504, allows the permanent generator to be load bank tested, with the load bank connection made at the outdoor docking station (no load bank cables running from the street to the generator room).
- Continuous Load Connection: The Foxfab dual-breaker design allows the building loads to maintain connectivity to the permanent emergency power source, while a technician is working to connect a portable generator to the docking station. This is not possible with docking station arrangements that utilize kirk keys on permanent generator output breakers, or on camlock access covers.
- Enhanced Serviceability: This arrangement enables servicing and load bank testing of the permanent generator WHILE the portable generator is available to (or actively feeding) the loads.
Benefits for Facility Owners
A Foxfab dual-breaker dual-purpose docking station in Configuration #504 offers these benefits:
1. Streamlined Interlock Operations
The integrated interlock mechanism is a standout feature of the Foxfab docking station. In other docking station arrangements, switching power sources may require operation of Kirk Keys that are located in different areas of the facility, often not in close proximity. In emergency situations, traveling from an outdoor docking station to a permanent generator located indoors (to open its output breaker), and back to the docking station (to close its connectivity to the portable generator), can lead to a substantial amount time that I think of as “emergency-power-naked” (the amount of time the facility is without an available emergency power source). The Foxfab dual-breaker design shortens this “naked” time by allowing interlock operations to be performed directly at the docking station.
Technical Insight:
- The set up of a portable generator can take considerable time. Aside from power cables, the technician must also make engine-start signal connections, and verify proper generator power output. The Foxfab dual-breaker design allows all of this to be performed while the permanent generator remains available to the building loads. Once the portable generator is made “available”, the Foxfab dual-breaker docking station ensures that load transfer is executed with minimal load interruption. Both permanent and portable generators may in fact be running simultaneously, but only one is connected to the building loads via the docking station’s integral circuit breakers.
2. Enhanced Serviceability and Testing
A significant post-installation challenge of emergency power systems is the ability to perform generator maintenance while ensuring minimal downtime. The use of a Foxfab dual-purpose docking station can be a big help in this area. More than just offering the physical point for connection of the load bank, Foxfab’s Configuration #504 allows the permanent generator to undergo load bank testing WHILE the portable generator is connected and actively supporting building loads.
Technical Insight:
- Load bank testing is often performed after major generator repairs to verify the permanent generator’s performance under simulated conditions, without impacting the actual building loads. As the permanent generator is undergoing maintenance or tests, a portable generator is expected to support the building loads in the event of a utility power outage. With the dual-breaker docking station design, the load may be fed by the portable generator, even when the permanent generator output circuit breaker is closed and connected to an active load bank. In other words, maintenance and testing activities do not need to be suspended, if there is a utility power outage. This is not possible on docking station designs that prevent access to the portable generator camlock panel until the permanent generator output is disconnected from the building loads, or designs that require the permanent generator breaker to be open before the portable generator can be closed unto the building loads.
3. Improved Safety and Simplicity
Safety is a paramount concern in power system design, and the Foxfab Configuration #504 docking station:
- Prevents cross-connection of power sources through a proven interlock mechanism that is fully incorporated within the docking station itself. There is no need to operate various devices at separate physical locations.
- Provides safe connection of a load bank at a predetermined outdoor location. No load cables running through the floor of a facility, no hauling load banks to an upper floor in a high-rise facility, and no improvised connections to the emergency switchgear.
- Ensures operator safety with an NEC-compliant switching arrangement, certified to UL/CSA Standards, and labeled clearly for the operator to confidently perform the necessary tasks.
By integrating these safety features, the docking station provides peace of mind to end-users, ensuring that the system operates reliably under all conditions.
4. Versatility and Scalability
The Foxfab FFCC-C3 and FFCC-P2 in Configuration #504 are suitable for a wide range of applications, from small commercial buildings to large residential or industrial facilities. Its design allows for customization based on specific project requirements, including voltage, current rating (up to 4000 amps), and enclosure types (NEMA 3R, 4X, in aluminum or stainless steel construction). This versatility makes it an excellent choice for design engineers looking to specify a solution that can perform in a wide range of facilities.
The bottom line?
The Foxfab FFCC-C3 and FFCC-P2 docking stations, when specified in Configuration #504, provide significant operational and safety benefits at a great value for the facility owner. For these reasons, I consider this arrangement to be “Best All-Around” for many of the typical applications in commercial and industrial projects.
The FFCC-C3 and FFCC-P2 Series docking stations are designed and manufactured by Foxfab Power Solutions in Surrey, BC. Learn more about the company and see our How to Specify… article for guideline specifications on these products.
Leveraging Specified.Works for Project Success
Want to work with Specified.Works for your next project?
Specified.Works helps you design, specify, and deliver the right docking station for your client. Here’s how!
- Access Detailed Product Information: Specified.Works provides comprehensive data on Foxfab docking stations, including job-specific technical specifications, drawings, and certifications. Designers will have all the information needed to develop their project plans and specifications.
- Simplify Product Selection: Specified.Works helps navigate through product design options to ensure that the selected product meets the project’s requirements.
- Generate Accurate Documentation: Specified.Works supports the design firm with detailed submittal packages, including drawings and data sheets, to have construction plans reflect the equipment accurately, improving communication with contractors and reducing the chance of errors during installation.
- Value Engineering: By reviewing progress plans, Specified.Works can identify design improvements that may represent costs savings for the overall project, without sacrificing long-term value for the end-user.