Emergency Transfer Cabinet

EMERGENCY TRANSFER CABINET.

A.) General.

1.) Emergency Transfer Cabinets are fully UL listed automatic transfer switches. They are designed for any application where power to adequate safety illumination; typical applications include public spaces such as hotel conference areas, office buildings, or theatre and concert hall house lighting.

2.) Emergency Transfer Cabinets sense the normal supply voltage and automatically transfer the load circuits to the emergency power feed(s) when a phase failure is detected. When the supply is restored, transfer back to the normal supply is also automatic.

B.) Mechanical.

1.) Cabinets shall be of sheet steel construction of no less than 16 gauge and shall be wall mounted as follows:

a.) 2 way Emergency Transfer Cabinet: Four 0.31" (6.35mm) mounting holes on 19" (482mm) horizontal and 21.875" (556mm) vertical centers.

b.) 4 way Emergency Transfer Cabinets: Four 0.44" (11.2mm) mounting holes on 22.75" (578mm) horizontal and 39.87" (1012mm) vertical centers

c.) 6 and 8 way Emergency Transfer Cabinets: Four 0.44" (11.2mm) mounting holes on 28.75" (730mm) horizontal and 45.87" (1165mm)

vertical centers.

2.) The cabinet shall be factory pre-wired and dressed. The contractor shall provide and terminate normal, emergency, sense and load wiring on screw terminals or lugs within the cabinet.

3.) Cable entry points shall be via the top, side and bottom panels of the cabinet. Note: 4" (100mm) clearance shall be required on the right hand side panel for test switch access.

4.) Normal feed, load terminals and single phase emergency feed terminals on the power switches shall accept up to #8 AWG, 3 phase emergency feed terminals up to #2/0 AWG wires. Sense terminals shall accept up to #14 AWG wires. All terminations and internal wiring shall be accessible via a hinged latched door.

5.) Emergency Transfer Cabinets shall be convection cooled and shall maintain the temperature of all components within the ambient temperature range defined in the Environmental Specification.

6.) Cooling fans shall not be required.

7.) The cabinet shall be finished in powder coat semi gloss light grey paint.

C.) Standards.

1.) The emergency Transfer Cabinet shall be UL listed and evaluated to UL1008 standard for safety, and shall comply with the requirements of NEC Articles 230-83, 700 and 701.

D.) Electrical.

1.) The Emergency Transfer Cabinets shall comprise voltage sensing circuitry and transfer switches to automatically transfer load circuits from the normal to the emergency power feed(s) when the normal supply fails.

2.) The Emergency Transfer Cabinets shall be designed for use with 120/208 volt 3Ph 4W dimmer cabinets or building services and shall be available in the following configurations:

a.) 2, 4, 6 and 8 (20A) load circuits each with an individual single-phase emergency power feed.

b.) 2, 4, 6, and 8 (20A) load circuits with a single 120/208 volt 3Ph 4W emergency power feed.

3.) The 3 phase emergency power feed shall have a maximum rating of 40A per phase for the 4 and 6 way cabinets, 60A for the 8 way cabinet.

4.) Emergency Transfer Cabinets for 3 phase emergency power feeds shall have a 20A magnetic branch breaker per load circuits.

5.) Breakers shall be rated for a minimum of 10,000A interrupting capacity.

6.) Voltage sensing relays shall cause automatic transfer when the voltage of one or more phases of the normal feed drops to 55% (i.e. 65 volts) or below.

7.) The transfer relays shall have both mechanical and electrical interlocks for safety.

8.) On restoration of the normal supply, load circuits shall be transferred from the emergency feed(s) to the normal supply automatically.

9.) An integral test switch shall be provided to simulate normal power source failure for periodic verification of system operation. Access inside the cabinet for test purposes shall not be necessary.

E.) Documentation.

1.) System riser and connection drawings shall be supplied as specified. Installation instructions shall be supplied with each Emergency Transfer Cabinet.

F.) Environmental Specification.

1.) For Emergency Transfer Cabinets and associated equipment, the following recommendations shall apply:

a.) Ambient temperature extremes: 32-104º Fahrenheit (0-40º C)

b.) Relative humidity: 10-90% non-condensing

c.) General conditions use only.

d.) Office level cleanliness - Interior