final bid specs 09328.pdf - Freese and Nichols, Inc.
final bid specs 09328.pdf - Freese and Nichols, Inc.
final bid specs 09328.pdf - Freese and Nichols, Inc.
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26 05 73.01 ELECTRICAL POWER SYSTEM STUDIES<br />
1.00 GENERAL<br />
1.01 DESCRIPTION<br />
General: This section specifies that the CONTRACTOR prepare a short circuit <strong>and</strong> relay coordination<br />
study <strong>and</strong> an arc flash hazard analysis for the electrical power system as shown on the plans.<br />
Short Circuit <strong>and</strong> Relay Coordination Study, Arc Flash Analysis<br />
The studies shall provide an evaluation of the electrical power system <strong>and</strong> the model numbers <strong>and</strong><br />
settings of the protective relays or devices <strong>and</strong> metering or motor monitoring devices for setting by the<br />
CONTRACTOR. The Studies shall include settings for all motor protective relays <strong>and</strong> electric system<br />
monitoring.<br />
A. Scope:<br />
1. The CONTRACTOR is responsible for providing all pertinent information necessary for the<br />
successful completion of the Short Circuit <strong>and</strong> Relay Coordination Study <strong>and</strong> Arc Flash<br />
Analysis. All cable <strong>and</strong> raceway data, data for existing motors, data from all new Switchgear,<br />
motor control centers, transformers, panelboards, <strong>and</strong> separately mounted fuses, starters or<br />
circuit breakers shall be obtained by the CONTRACTOR. Obtain all existing or new<br />
protective device information to include all present settings. The CONTRACTOR shall obtain<br />
any needed data or information from Contract Documents, various suppliers, the Electric<br />
Utility <strong>and</strong> from conducting his own field investigations. The data obtained shall be organized<br />
<strong>and</strong> submitted to the ENGINEER to show that all the necessary data gathering work has<br />
been done.<br />
2. Calculations shall utilize actual X/R <strong>and</strong> three phase short circuit values obtained by the<br />
CONTRACTOR from the Electric Utility. The use of infinite bus fault current calculation is not<br />
acceptable.<br />
3. The studies shall model the electrical distribution system feeding the building all the way back<br />
to the Utility owned transformer. Contractor shall include all loads normally fed from the utility<br />
owned transformer.<br />
4. Provide a complete short circuit study. <strong>Inc</strong>lude three phase <strong>and</strong> phase-to-ground<br />
calculations. Provide an equipment interrupting or withst<strong>and</strong> evaluation based on the actual<br />
equipment <strong>and</strong> model numbers provided on this project. Generic devices are not acceptable.<br />
Normal system operating method, alternate operation, <strong>and</strong> operations that could result in<br />
maximum fault conditions shall be thoroughly addressed in the study. The study shall assume<br />
all motors operating at rated voltage with the exception that motors identified as "st<strong>and</strong>by"<br />
shall not be included. Electrical equipment bus impedance shall be assumed zero. Short<br />
circuit momentary duties <strong>and</strong> interrupting duties shall be calculated on the basis of maximum<br />
available fault current at the electrical equipment busses. The Study shall be performed<br />
using actual available short circuit currents available <strong>and</strong> system impedances as obtained<br />
from the Electric Utility. An assumption of infinite bus for the purposes of the Study is not<br />
acceptable. Study shall use actual motor X/R <strong>and</strong> subtransient reactance data obtained from<br />
equipment suppliers.<br />
Electrical Power System Studies 26 05 73.01-1<br />
DRP09328
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