Milsoft Utility Solution’s Arc Flash Analysis software facilitates faster and easier assessment of arc flash hazards and electrical incident analysis. Identify and analyze high risk arc flash areas in your electrical power system with greater flexibility by simulating and evaluating various mitigation methods in your arc flash study.

1. Arc Flash Review:
Requirements, Results, Issues,
and Strategies
Keith Mullen, P.E.

2. Arc Flash Review
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WindMil & LightTable Requirements
Consensus Standards
Analysis Methodology
Sample Results
Issues Uncovered
Hazard Reduction Strategies
Assessment Integration
Questions

3. Arc Flash Review: Requirements
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Accurate Connectivity Model
Up-to-Date Source Impedances
Complete Equipment & Device Definitions
Add Transformer Protection
Accurate Construction Codes
Establish Device Links to LightTable
Analysis Parameters Based on Operating Practices

4. Arc Flash Review: Standards
NFPA 70E
Hazard/Risk Categories
Hazard/Risk
Categories
Calculated Arc Energy
(Cal/cm2)
(J/cm2)
0
1.2
5.0
1
4.0
16.7
2
8.0
33.5
3
25.0
104.6
4
40.0
167.4
>4
> 40.0
>167.4

5. Arc Flash Review: Standards
IEEE Standard 1584 Method
 Voltages from 208V to 15,000V
 Frequency from 50Hz to 60Hz
 Bolted fault currents from 700A to 106,000A
 Grounding of all types and ungrounded
 Equipment enclosures of commonly available sizes
 Gaps between conductors from 13mm to 152mm
 Faults involving three phases

6. Arc Flash Review: Standards
IEEE 1584
Factors for Equipment and Voltage Classes
System Voltage
(kV)
Typical Gap Between
Conductors (mm)
Distance Factor
10-40
2.000
Switchgear
32
1.473
MCC & Panels
25
1.641
Cable
13
2.000
Open Air
102
2.000
13-102
0.973
13
2.000
13-153
2.000
Switchgear
153
0.973
Cable
13
2.000
Equipment Type
Open Air
0.208 - 1
>1-5
Switchgear
Cable
Open Air
> 5 - 15

7. Arc Flash Review: Analysis Methodology

8. Arc Flash Review: Sample Results

9. Arc Flash Review: Sample Results

10. Arc Flash Review: Sample Results

11. Arc Flash Review: Sample Results

12. Arc Flash Review: Sample Results
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Lee method is the most conservative
IEEE method is more conservative than
ARCPRO at low-end fault values
IEEE method and ARCPRO yield consistent
results at various fault levels
Parameters in the NESC Table 410.1 must align
with equipment specifications and operating
practices

13. Arc Flash Review: Sample Results

14. Arc Flash Review: Sample Results

15. Arc Flash Review: Requirements
Urban System
 Feeder breaker and fuses clearing faults
 Limited variations in faults and clearing times
Rural System
 Larger variety and layers of protective devices
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Significant variations in faults and clearing times

16. Arc Flash Review: Sample Results

17. Arc Flash Review: Sample Results

18. Arc Flash Review: Sample Results

19. Arc Flash Review: Sample Results

20. Arc Flash Review: Sample Results

21. Arc Flash Review: Sample Results
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Transformer protection is critical to arc
clearing time
System impedance can influence calculated
hazard levels on transformer low-side
Line devices upline of transformer fuse can
reduce arc clearing time
Arc flash results can be significantly impacted
by transformer impedance

22. Arc Flash Review: Issues & Strategies

23. Arc Flash Review: Issues & Strategies

24. Arc Flash Review: Issues & Strategies

25. Arc Flash Review: Issues & Strategies

26. Arc Flash Review: Issues & Strategies

27. Arc Flash Review: Integration
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Operating procedures and clothing systems
should align with arc flash results
Hazard levels should be re-evaluated with
changes to system configuration and fault levels
Adjustments to coordination scheme should
include an arc flash assessment
Planning studies should include the impact of
recommendations on hazard levels

28. Arc Flash Review: Questions
Keith Mullen
Senior Engineer & Project Manager - Nashville
R. W. Beck, Inc.
tel 615.431.3212 fax 615.824.7570
131 Mir Parkway, Suite 300
Hendersonville, TN 37075
kmullen@rwbeck.com