Conditioned Power Center 21
Section 5 - Installation
5.6.2 Output Voltage Fine Adjustment
The transformer secondary of the power conditioners is a 5 wire
Wye configuration (three phase conductors, one neutral and one
safety ground). Output voltage can be adjusted plus-or-minus five
percent ( + 5%) (as shown in Figure H to the right) to accommodate
site-specific voltage differences . This is accomplished by moving
the output lugs and connections on the transformer secondary.
Consult the information found in Section 10.4 on page 37 of this
manual for detailed information on the location of the transformer
secondary taps and the settings necessary to make fine
adjustments up or down.
IMPORTANT! Output power feeds connect directly to the lugs provided at the transformer secondary. If
the CPC series power conditioner is equipped with the Power Management Option, it will be necessary (if
changing output voltage taps) to also move current transformers to the appropriate transformer
secondary tap at the same time the output lug and associated wiring is moved.
The presence of a code legal safety ground on both the input and the output
circuits of the power conditioner is required to prevent fire hazards and to ensure
personnel safety. If a safety ground connections cannot be made or are made
incorrectly, do not proceed with the installation until this problem is corrected. Failure to observe this
warning may result in fire or electrical shock hazard in the event of an electrical fault.
The CPC series product family is considered to be information technology equipment for the purposes of the
National Electrical Code as defined in NEC Article 645. Before proceeding, please review any requirements for
proper grounding of the conditioner. This is critical for proper operation as well as personnel safety and fire
prevention. Grounding requirements and guidelines can be confusing. Contact the manufacturer if you are unsure
about proper grounding methods or techniques.
The National Electrical Code (NEC), in Article 250-20d, describes a "separately derived system" as one in which
the output neutral is bonded to safety ground. The key advantage of such an arrangement is the complete
elimination of neutral to ground (common mode) voltages and noise at the point of power delivery to a critical
load. The power conditioner meets all the requirements for a separately derived system as defined by U.S. and
Canadian electrical codes.
Figure H