ADCP-80-575 • Issue 2 • December 2006

1.12 Ground Connectors

Two #10 studs (with nuts) are provided for grounding the fuse platform chassis. The studs are mounted on 0.625 inch (15.875 mm) centers.

Two crimp ring lug terminals for two #10 AWG wires are provided with each fuse platform. The fuse platform may be grounded using only one stud.

1.13 Alarm Contact Operation

The fuse platform contains circuitry that opens and closes a set of alarm contacts when any fuse on the bus fails or when input power to the bus is lost. These contacts may be used to open or close a loop connected to an external alarm system.

The alarm circuitry uses form C alarm relay dry contacts. During normal operation (power applied and all fuses operational), the normally open (NO) contacts remain open and the normally closed (NC) contacts remain closed. When a fuse fails on either bus or power to either is lost, the NO contacts close creating a connection from NO and common and the normally closed (NC) contacts open creating an open circuit between NC and common. The current rating for each set of alarm relay contacts (either two or three sets of contacts are provided) is 110 Vdc/125 Vac maximum voltage, 1.0 Amp maximum switching current.

1.14 Alarm Contact Connectors

The fuse platform is available with either screw-down barrier terminal strips or wire wrap pins for the alarm contact connections. The following describes both types of contact connections:

Warning: Use of one bus only on a dual bus panel will result in false alarms for the unused bus. Power is required on both buses on a dual bus panel for normal operation.

•Screw-down barrier terminal strip: Six terminals with 3-48 screws are mounted in a barrier type terminal block. The terminals are on 0.25 inch (6.35 mm) centers with a maximum distance between barriers (maximum connecting terminal width) of 0.20 inch (5.08 mm). The alarm terminal strip has two sets of three terminals (NO, C, and NC) for use with two alarm systems. The terminals can accept #16 to #30 AWG copper wire with insulation stripped back. In selecting wire size, follow local code referring to the ampacity guidelines provided in Appendix A of this manual.

•Wire-wrap terminal block: Nine wire-wrap pins are mounted in a terminal block for both buses. The alarm terminal block has three sets of three wire-wrap pins (NO, C, NC), for use with three alarm systems. The wire-wrap pins can accept #22 to #26 AWG copper wire with insulation stripped back. In selecting wire size, follow local code referring to the ampacity guidelines provided in Appendix A of this manual.

1.15Fuse Alarm Indicators

A visual fuse alarm indicator (red LED) is provided on the front of each fuse holder module. The fuse alarm indicator lights when any fuse in the corresponding fuse holder fails. The fuse

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© 2006, ADC Telecommunications, Inc.