HomeMy WebLinkAbout105F ARC FLASH AND FAULT CURRENT - 23-00093 - Liberty GMC - ElectricalWeb Sites:
https://www.rockymountainpower.net/working-with-us/business-customers/arc-flash-fault-current.html
https://www.pacificpower.net/working-with-us/business-customers/arc-flash-fault-current.html
Revisions
Arc Flash
Arc flash analysis determines the arc flash boundary, the incident energy at working distance, and the level
of personal protective equipment required for personnel to work within the arc flash boundary.
The Occupational Safety and Health Association (OSHA) and National Fire Protection Association (NFPA)
mandate arc flash analysis to determine the Hazard Risk Category (HRC) which establishes the level of Flame
Resistant (FR) clothing required for personal protection.
NFPA 70 E, Article 130.5 states, "The arc flash hazard analysis shall be updated when a major modification or
renovation takes place, and is to be reviewed periodically, not to exceed 5 years.
Secondary Fault Current
NFPA 70 (National Electric Code), Article 110.24 requires electrical service panels be labeled with available
fault current. This helps ensure properly sized equipment is installed, reducing the probability of damage
caused by electrical faults.
Electrical power system fault duties tend to increase as systems are modified. Rocky Mountain Power and
Pacific Power's policy is to provide secondary fault current at the transformer assuming an infinite source.
Tables found in tab "Fault Current Infinite Bus" provide these values. Transformer size must be confirmed.
Customers must submit*the following information on the "Request Form":
·Facility Point Numbers(s) see Fig#1 on "Request Form" tab
·Service Voltage (240/120, 208Y/120, 480Y/277)
·Phase (Single-Phase, Three-Phase)
*Call 1-888-221-7070 for "Request Form" submittal information
Arc Flash Request
Upon receipt of completed "Request Form" customer is provided:
·System Impedance on primary side of distribution transformers
·Average transformer impedances
·Transformer fusing information
Secondary Fault Current Request
Upon receipt of completed "Request Form" customer is provided:
·Transformer size
·Fault Current Infinite Bus table
Disclaimer
Rocky Mountain Power and Pacific Power recommend customers de-energize electrical conductors when contact or faults
are possible. In providing the information contained herein, the recipient acknowledges and understands that Rocky
Mountain Power and Pacific Power provides this information based on the information in its files and other information
available to it at the time of the request. The data will change over time based on changes in load and other dynamic
elements of Rocky Mountain Power and Pacific Power's electrical system. Rocky Mountain Power and Pacific Power has
not independently verified the accuracy of this information for the purposes for which it may be used by the recipient.
Furthermore, recipient understands and acknowledges that Rocky Mountain Power and Pacific Power has no
Commercial and Industrial Arc Flash and Secondary Fault Current Information Requests
Each year Rocky Mountain Power and Pacific Power provide arc flash and secondary fault current information
to electrical consultants and electricians. To ensure consistency Rocky Mountain Power and Pacific Power
utilize an Arc Flash/Secondary Fault Current "Request Form".