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Electrical Installation
Field wiring must comply with all federal, state and local regulations. Circuit breakers, fuses, wiring and wire size must be installed per the National Electric
Code (NEC). Voltage applied to Multistack chillers must be within plus/minus 10 percent of nameplate voltage. Voltage imbalance between phases may
not exceed two percent. According to NEMA Standard MG-1-1998, a two percent voltage imbalance will cause a current imbalance of six to 10 times the
voltage imbalance. Voltage imbalance between electrical phases must be kept to a minimum. Most Multistack chillers come with a single point of electrical
connection (up to 500 amps) to simplify installation. The main electrical conduit feeding the power junction box may enter from either the top, bottom,
or left side of the panel when facing the panel. Chillers requiring more than 500 amps will have multiple electrical connection points (per the 500 amp
requirement).
Optional Single Module Field Connection
For single module installations, the power junction box can be deleted, but a power phase monitor must be installed. The main electrical feed can connect
directly to the module circuit breaker.
Junction Box Support Electrical Junction Box
Junction Box Support Leg
1. Attach the electrical junction box support. Line up the orange posts to ensure support is not backwards. The threaded plate slides in between frame.
2. The electrical junction box may be installed on either end of the chiller module.
3. Remove cover plate on appropriate end of the junction box, then bolt junction box to the support.
4. Cut the junction box support leg to length and fasten to the bottom of box and then to the oor, if necessary.
5. Three-phase wire and the ground wire, sized according to the nameplate rating, should be run through the junction box.
Buss bar Installation
NOTE: Contact the local Multistack representative before installing the buss bar. Depending on the start-up representative’s policy, the attachment of
the buss bar system, and power phase monitor to the electrician’s wire and lugs may be the responsibility of the electrician or the Multistack autho-
rized start-up technician.
1. Remove the buss duct covers. 2. Remove the isolation switch cover
NOTE: There is a dedicated chiller ground in this panel that must connect to a true earth ground.
DANGER: To avoid the risk of electrical shock, personal injury or death, disconnect all electrical power to the unit before performing any mainte-
nance or service. The unit may have more than one electrical power supply. Assume all electrical wires are live, energized wires. Use lockout/tagouts.
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