THE
OBJECTIVES:
a)
Determine if the potential for a hazardous arc-flash exists
in equipment workers
may work on or near while the equipment is exposed and energized.
b) Determine the minimum safe working distance (arc-flash
boundary) from the
equipment.
c) Determine the appropriate PPE required to avoid a permanent
injury from an arcflash.
d) Reduce or eliminate as many of the potential arc-flash hazards
identified in the
analysis as possible.
e) Inform workers of the results and provide the arc-flash
hazard training required
for “qualified persons”.
Want to
know more about completing an Arc-Flash Hazard Analysis or
the cost of each
of the following four phases – contact John Klingler,
PE at:
Klingler Electrical Safety, LLC
812-240-9134
John@KlinglerElectricalSafety.com
PHASE I - SITE ASSESSMENT AND DATA COLLECTION
The first phase of any arc-flash hazard analysis is the
collection of field data necessary to
calculate potential incident energy at power distribution
equipment. Phase I is the labor
intensive phase of the arc-flash hazard study, typically
taking half of the total effort
required to complete the analysis. Data is collected
on-site by qualified persons in
appropriate PPE; preferably assisted by a qualified
facility employee or someone
knowledgeable of the plant electrical equipment and
facility layout. Availability of
facility one-line electrical drawings can be very
helpful in the data collection process.
Data collected for the analysis is similar to that
required for short-circuit and protective
device coordination studies; including transformer
nameplates, conductor sizes/number
per phase/lengths, motors larger than 75HP, circuit
breaker catalog numbers and settings,
fuse catalog numbers, and on-site generator nameplates.
Generally all the data is
collected without disturbing facility operations.
Proper labeling of each disconnect - as to
its purpose (in accordance with NEC® 110.22),
is required in order to complete an
accurate analysis. If the facility has overhead plug-in
buss ducts a man-lift and operator
must be provided to collect the information.
Authorization and contact information are required
to contact the servicing electric utility
to provide the available fault MVA and power angle
or X/R ratio for the facility.
PHASE II - ENGINEERING CALCULATIONS AND HAZARD ANALYSIS
Phase II is a multi-facetted phase beginning with
the input of the data from the one-line
diagrams and collected data into the PTWprogram developed
by SKMSystems
Analysis, Inc. Using the PTWprogram the following
values are determined for each
point of concern in the facility.
-
Bolted fault current
- Arc fault current
- Fault clearing time
- Arc-flash boundary
- Personal protective clothing requirements
This
information will be provided in the “Arc-Flash Hazard
Analysis” report.
The report will also include “Findings” of
concern: 1) inadequate interrupting ratings, 2)
improper coordination of protective devices,
and 3) an itemized list of arc-flash hazards
greater than a Hazard/Risk Category 1, and most
importantly, “Recommendations” for
corrective actions for each of the “Findings” of
concern.
Phase II is completed or reviewed and approved by a licensed Professional
Engineer.
PHASE III - REPORT PRESENTATION, LABELING, AND
CONSULTING
Phase III includes delivery of the report and
a presentation of the results of the “Arc-
Flash Hazard Analysis” including “Findings” and “Recommendations”.
The NEC®and NFPA 70E require labeling of equipment
to warn of potential arc-flash
hazards. Subject to the requirements of the
facility, labels are provided for each analyzed
point of concern.
The labels provide information about voltage, arc-flash boundary, and required PPE.
As part of Phase III, consulting assistance
can be provided to develop or update the
facility’s Electrical Safety Program and Electrical Policies
to address the “Findings” of
the Arc-Flash Hazard Analysis. This may also
include assistance in selection of the
appropriate PPE.
PHASE IV - TRAINING
Completion of the arc-flash hazard analysis
requires proper training. The training
provided is designed specifically for electricians,
technicians, contractors, vendors and
service personnel. It covers the electrical
safety topics required for “qualified” persons
and can be customized to cover the facility’s
Electrical Safety Program and Electrical
Policies. This training is provided on-site
at times selected by the facility. The training
can be a one-day class covering only NFPA 70E
and the results of the arc-flash hazard
analysis, or a two-day class including the
facility’s
Electrical Safety Program, Electrical
Policies, and other pertinent electrical safety
subjects.
