When selecting an ASCO transfer switch, discussions often reference the term frame type. This article explains the term and its relevance to switch ratings.
Background Information
Selecting a transfer switch involves ensuring that its ratings meet or exceed the requirements of the application in which it will be used. For ASCO transfer switches, ampacity ranges are grouped into different frame types. Understanding frame types is useful in discussing transfer switch selection and is referenced when transfer switches are ordered.
ASCO Frame Type Basics
For ASCO transfer switches, models are organized, in part, by frame type. This refers to the specific category of the transfer switch, which includes amperage range, internal cabling and bus, connectors, switching mechanisms, controllers, communication devices, mechanical bracing, accessories, and more.
A specific type of frame can be used to build models with different ampacities. For instance, an ASCO SERIES 300 J-frame transfer switch can be obtained with ampacities ranging from 150 to 600 Amps (A). If an application requires a greater ampacity, then a different frame type must be used.
ASCO Withstand and Closing Ratings Table
The amount of current that ASCO Switches are rated to carry is specified in a table of Withstand and Closing Ratings (WCRs). An abbreviated WCR table for ASCO SERIES 300 transfer switches is shown in Figure 1. When selecting any ASCO transfer switch, users should refer to the latest version of the table for ASCO 7000, ASCO 4000, or 300 series switches, which can be accessed by searching for Engineering Application Information - Withstand and Closing Ratings For Transfer Switch Equipment (Publication 1128) on the ASCO Power Technologies website. For more information regarding WCR ratings, see the ASCO White Paper entitled UL1008 Transfer Switch Withstand and Closing Ratings.
Background Information
Selecting a transfer switch involves ensuring that its ratings meet or exceed the requirements of the application in which it will be used. For ASCO transfer switches, ampacity ranges are grouped into different frame types. Understanding frame types is useful in discussing transfer switch selection and is referenced when transfer switches are ordered.
ASCO Frame Type Basics
For ASCO transfer switches, models are organized, in part, by frame type. This refers to the specific category of the transfer switch, which includes amperage range, internal cabling and bus, connectors, switching mechanisms, controllers, communication devices, mechanical bracing, accessories, and more.
A specific type of frame can be used to build models with different ampacities. For instance, an ASCO SERIES 300 J-frame transfer switch can be obtained with ampacities ranging from 150 to 600 Amps (A). If an application requires a greater ampacity, then a different frame type must be used.
ASCO Withstand and Closing Ratings Table
The amount of current that ASCO Switches are rated to carry is specified in a table of Withstand and Closing Ratings (WCRs). An abbreviated WCR table for ASCO SERIES 300 transfer switches is shown in Figure 1. When selecting any ASCO transfer switch, users should refer to the latest version of the table for ASCO 7000, ASCO 4000, or 300 series switches, which can be accessed by searching for Engineering Application Information - Withstand and Closing Ratings For Transfer Switch Equipment (Publication 1128) on the ASCO Power Technologies website. For more information regarding WCR ratings, see the ASCO White Paper entitled UL1008 Transfer Switch Withstand and Closing Ratings.