ETC Unison DRd Dimming Rack Enclosure - Manual (Page 9)

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Prepare for Installation 5
C h a p t e r 1
Prepare for Installation
Unpack and Inspect
Before you begin installation, check your shipment and confirm it arrived complete and
undamaged.
Step 1: Check the shipping container for physical damage.
Step 2: If you find damage, document it to help with a claim against your shipper.
Step 3: Unpack your order and check the contents against the packing list to be sure
your order is complete.
Step 4: If you discover a problem, call the ETC Systems Group the closest office of
purchase. See “Contacting ETC” on page 2.
Main Circuit Breaker Protection
Before you begin installing the DRd enclosure, make sure you have installed a main circuit
breaker cabinet or other readily accessible input power disconnect device. In certain
bussed and cross-bussed systems, this disconnect device may be the Unison AX series
auxiliary enclosure with a main circuit breaker.
Using 90° Copper Wire
To comply with UL requirements:
Use Copper Conductors Only, the torque rating for each Non-Class 2 field-wire
connector, and “Use 90°C conductors at the 75°C Ampacities”, where readily visible in
the field wiring compartment; Class 2 adjacent to each Class 2, field-wiring connector.
Use only 90°C-rated copper wiring installed in accordance with all applicable local electrical
codes.
W A R N I N G : DRd enclosures installed without an accessible power disconnect device
cannot be serviced or operated safely. Follow all local codes and
restrictions.
Before removing dimmer or control modules for service, de-energize main
feed to DRd and follow appropriate Lockout/Tagout procedures as
described in NFPA Standard 70E. It is important to note that electrical
equipment such as dimmer enclosures can present an arc flash safety
hazard if improperly serviced. This is due to available large short circuit
currents on the feeders of the equipment. Any work on energized equipment
must comply with OSHA Electrical Safe Working Practices.
C A U T I O N : A two-wire circuit with separate hot and neutral conductors is required for every
branch circuit that will be connected to the DRd enclosure. Shared neutral (multi-
wire) branch circuit arrangements are not recommended for phase control
dimming systems due to harmonics and potentially elevated neutral currents in a
shared neutral arrangement.
For retrofit installations where shared neutral circuits are already installed, or
enclosure lighting installations where the enclosure has a shared neutral, consult
ETC Technical Services for installation guidelines.