Specifications

PIP ELCGL01
Electrical Design Criteria November 2002
Page 8 of 20 Process Industry Practices
3.8 Design Allowance
3.8.1 New electrical systems shall be designed with a minimum spare capacity as
specified on the Data Sheet. Design allowances beyond the minimum
requirements of the NEC shall be applied in sizing feeder circuits,
transformers, switchgear buses, and motor control center (MCC) buses to
allow for future load growth.
3.8.2 Spare devices as specified on the Data Sheet shall be included with the
following equipment:
a. medium-voltage (MV) switchgear, motor starters, and switch lineups
b. low-voltage (LV) switchgear
c. LV MCC branch breakers, fused switches, and starters
3.8.3 Equipped and unequipped spaces as specified on the Data Sheet shall be
included in the following equipment:
a. MV switchgear and motor starters
b. LV switchgear
3.8.4 Future unit spaces as specified on the Data Sheet shall be included in LV
MCCs.
3.8.5 Adequate space shall be provided to accommodate electrical equipment to
effectively use the capacity of the system.
3.8.6 Equipped spaces shall be furnished with all hardware, wiring, doors, and
miscellaneous equipment, including current transformers and monitoring
devices required to permit completion of the unit by the addition of only a
circuit breaker or medium-voltage starter. Equipped spaces shall be capable
of being safely placed in service without shutdown of switchgear or motor
control center lineup. Unequipped spaces shall be provided with doors but
with no other equipment for future use except the power stabs. Unequipped
spaces shall not be used for mounting control switches and other auxiliary
equipment. Power stabs (both line and load side) shall be provided with
covers to prevent accidental contact with live parts when door is opened. For
MCCs, future unit spaces shall be provided with bus and a blank door.
3.9 Power Factor
Power factor shall be corrected as specified on the Data Sheet.
3.10 Harmonics
Power systems that include electronic switching devices shall be designed so that the
total harmonic distortion meets the requirements of IEEE 519.
3.11 Electrical Equipment Rooms
3.11.1 Electrical equipment rooms or walk-in enclosures shall have a minimum of
two doors at opposite ends of the room unless specified otherwise on the
Data Sheet.