Requirements and Expectations for
Electrical Hazard Assessment Projects in
Water and Wastewater Facilities
Presented by: Jay Bielanski, PE,
October 14, 2014
Topics
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Arc flash event
Introduction to electrical hazard analyses
Analysis software
Coordination with electric utility companies
Owner/operator efforts
Coordination of equipment shutdowns
Field collection
Assumptions to complete the study
Arc flash labels
Mitigation strategies
Project costs
Updating the study
Electrical safety program
Arc Flash Event (HRC 3)
Video by Westex, Inc.
Arc Flash Event
Introduction to Electrical Hazard Analyses
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Increase employee safety
Regulatory requirements
– OSHA – 29 CFR Part 1910 – Occupational
Safety and Health Standards
– NFPA 70 – National Electrical Code
– NFPA 70E – Standard for Electrical Safety in the
Workplace
Insurance requirements
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Introduction to Electrical Hazard Analyses
• National Fire Protection Association 70E (NFPA)
• Arc Flash Study
– Arc flash boundary
– Incident energy at the working distance
– Personal Protective Equipment required
• Short Circuit Study
– Ability of the system equipment to handle fault
conditions
• Coordination Study
– Optimal trip settings for selectivity, equipment and
personnel protection
• Shock Hazard Analysis
– Voltage exposure
– Boundary requirements
– Personal Protective Equipment required
Analysis Software
• Software Options
– PowerTools by SKM Systems Analysis
– Network Analysis and Protective Device Coordination by
ETAP
– Arc Flash Suite by EasyPower
Software
SKM
ETAP
EP
Short Circuit
Arc Flash
Coordination
Equipment
Evaluation
Coordination With
Electric Utility Companies
Coordination with
Electric Utility Companies
• Request For Information
Primary service voltage
Secondary voltage
Transformer size
Transformer nameplate impedance
Transformer connection type
Transformer primary protective device
Available three phase fault contribution at the transformer primary
Available single phase to ground contribution at the transformer
primary
– Three phase X/R ratio at the transformer primary
– Single phase to ground X/R ratio at the transformer primary
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Utility A
Utility B
Utility C
Coordination with
Electric Utility Companies
• Data received is often:
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Inconsistent
Maximum fault current values used for sizing services
Minimum or design guideline values for transformers
Estimated, rounded or manipulated numbers
Incorrect or missing!
• Experience is required to interpret data
• Assumptions and estimations may be necessary
to provide realistic results or complete the study
Recommendations
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Electric utility contact should be the first action item!
Letter of authorization from owner to utility
Backup plan in case the utility does not follow through
Be sure that work is accomplished while waiting for a
response
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Field investigation
System modeling
Develop operating scenarios
Prepare deliverables for review (reports, labels, electrical
safety program)
Availability of Facility Drawings
Availability of Facility Drawings
• Factors affecting usefulness of drawings
– Type (as-built, design, shop)
– Date
– Accuracy
• One lines and plan drawings = faster
modeling, field collection and labeling
Availability of Facility Drawings
• Case 1
– 70+ facilities included in survey
– Drawing for only 10% of facilities
– Hand drawn one lines and
elevations were created
Availability of Facility Drawings
• Case 2
– 7 facilities
– No drawings
– As-built CADD drawings were created
as part of project scope
Availability of Facility Drawings
• Case 3
– 15 facilities
– As-built for 80% of facilities
including record drawings of WWTP
projects from 1955 through 2013
– No separate drawings required
Recommendations
• Drawings should be gathered at project inception
• Availability of drawings should be made known to bidders
– Impact on cost and schedule
• If you do not have good drawings, make them a
deliverable!
• Be aware of the effect on the project budget and schedule
• Provide all available information at project kickoff
Owner/Operator Staff
Owner/Operator Staff
• Determine availability of staff
– Designate a tour guide
– Determine the level of assistance to be provided
– Provide an employee able to answer questions
• Develop operating scenarios
– What pumps are running in high and low flow events
– What tie breakers are operated in contingency events
– Are there alternate utility or generation sources
Access to Facilities
Access to Facilities
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Have a schedule and a plan
Follow the schedule and plan!
Ensure all parts of facilities are accessible
Provide a point of contact for each facility should a
revisit be required
Coordination of Equipment Shutdowns
Coordination of Equipment Shutdowns
• THINK SAFETY!
• Is a shutdown possible without impacting
process?
• If it is possible, schedule an outage
• What duration is required for complete collection?
• Have a contingency plan
Coordination of Equipment Shutdowns
• Determine what can be collected without a
shutdown
– Nameplates – Motor control centers, panelboards,
motors, transformers
– Equipment locations and circuit length
Coordination of Equipment Shutdowns
• Determine what might
require a shutdown
– Motor control centers
– Large panelboards,
switchboards, switchgear
– Disconnect switches
– Service entrance equipment
– Equipment that is old or in
poor condition
Recommendations
Coordinate efforts at project kickoff
Develop points of contact
Determine staff availability
Schedule facility access
Schedule equipment shutdowns
Schedule utility outages
Procedure for revisits
Think safety
Prepare to use assumptions where data is not
available
• Have a schedule and a plan
• Impact on cost and schedule
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Field Collection
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Field Collection
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ORGANIZATION!
One-lines
Data sheets
Photos
Data Sheets
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Switchgear (low or medium voltage)
Switchgear cubicles
Motor control centers (MCC)
Motor control center cubicles
Transformers
Generators
Panelboards
Automatic Transfer Switches (ATS)
Motors
Variable Frequency Drives (VFD)
Disconnects (switches, circuit breakers)
Photos
• Good photos can be the most useful tool
• Paint a clear picture of the layout of a facility
• More is better – if they’re organized!
Photos
Recommendations
• Determine deliverables
– One lines/as-built information
– Datasheets/asset information
• Opportunity to add value
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One-line drawing development or verification
Condition assessment
Power reliability/redundancy analysis
Asset management synergies
Engineering Assumptions to Complete
the Study
Engineering Assumptions
• Engineering assumptions are necessary to
complete the study when reliable information
cannot be provided or is not available
• Study parameters (i.e. utility input data)
• Equipment (i.e. cable lengths, SCCRs)
Engineering Assumptions –
Study Parameters
• Utilities often provide maximum possible fault
current output or a wide range of parameters
• NFPA 70E: “Both larger and smaller available
short-circuit currents could result in higher
available arc flash energies.”
• Example:
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Utility transformer: 750kVA
Transformer impedance:
Calculated fault current:
Difference:
MAX = 5.00% MIN = 1.9%
= 18051 A
= 47501 A
= 29450 A
Engineering Assumptions –
Study Parameters
• Operating modes
– What equipment is operating at minimum and
maximum flows?
– What tie circuit breakers are operated in contingency
events?
– Are there standby generators or alternate utility
services?
Engineering Assumptions –
Equipment
• Short circuit current ratings
– Conservative ratings
• Circuit breakers
– Highest possible settings provide conservative results
• Cables
– Sized per National Electrical Code, lengths estimated
• Transformers
– Sized per manufacturer’s application guides
Arc Flash Labels
Arc Flash Labels
• What equipment gets labeled?
• 2011 NEC 110.16 Arc Flash Hazard Warning:
“Electrical equipment, such as switchboards, panelboards,
industrial control panels, meter socket enclosures, and
motor control centers, that are in other than dwelling units,
and are likely to require examination, adjustment,
servicing, or maintenance while energized shall be field
marked to warn qualified persons of the potential electric
arc flash hazards.”
4 Enclosures
36 Enclosures
Arc Flash Labels
• How many labels for larger equipment?
71
6 Labels
Labels
Label Format
• Labels must have at least one of the
following:
– Available incident energy and the corresponding
working distance
– Minimum arc rating of clothing
– Required level of Personal Protective Equipment (PPE)
– Highest Hazard/Risk Category (HRC) for the equipment
• Nominal system voltage
• Arc flash boundary
Label Format
Recommendations
Owner/operator preference for design
What fits with the safety program
Education and training
Label requirements should be established at
project inception and should be consistent
• Impact on cost and schedule
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Mitigation Strategies
Mitigation Strategies
• Low cost
– Settings changes
Mitigation Strategies
• Medium cost
– Fuse replacement
– Breaker
replacement
– Relay replacement
– Trip unit upgrades
– ARMS devices
Mitigation Strategies
• High cost
– Zone Selective
Interlocking
– Optical relays
– Differential
protection
Recommendations
• Explore all options (One size does not fit all!)
Existing settings
Equipment upgrades
Equipment replacement
Advanced strategies
• Remove the worker from the hazard
– Remote operation, remote racking, mimic
panels
Project Costs
Project Costs
• Many determining factors
– How many facilities? What sizes?
– What equipment is included in the study?
– What level of field collection effort is required?
– What equipment is being labeled? How many
labels?
– Are there additional services?
• Electrical Safety Program, CAD drawings, Condition
Assessment, Training
How Many Zeroes Do I Need?
• Small pumping station
– ≈$5,000 - $15,000
• Large pumping station
– ≈$10,000 - $50,000
• Small – mid size treatment plant
– ≈$25,000 - $50,000
• Large treatment plant
– ≈$50,000 - $150,000+
Updating the Study
Recommendations
• Required by NFPA 70E
• Update after any major modifications are
made to the electrical distribution system
– What is a “major” modification?
• Review the study every five years
Electrical Safety Program
Electrical Safety Program
• Do not view the project as a requirement; view it as a
tool!
• Educate personnel – electrical safety program
• Have a consistent electrical safety program at all
facilities
– Consistent labels
– Consistent procedures
• Know how to interpret labels
• Two-level clothing system and other methods to
improve ease of use
Two Level Clothing System
Category 2
Category 4
Summary
• Assemble all facility data and plan to make it
available to potential bidders
• Make important decisions at project inception
• If you do not know, ask!
QUESTIONS?
Thank you for your time!
jbielanski@greeley-hansen.com