OSHA Electric Arc Flash Protection

Electric Power Generation,
Transmission, and Distribution
Electrical Protective Equipment—
Electric Arc Protection
Electric Arc Protection
Electric Arc Protection
CON EDISON ARC FLASH DOCUMENTARY
Principle Requirements
Assess workplace for hazards from flames or
electric arcs
If there is exposure, estimate incident energy
Prohibit clothing when incident energy could ignite
clothing
Require FR under certain conditions
Select clothing with an arc rating greater than the
estimated incident energy
§1910.269(l)(8) & §1926.960(g)
Appendix E Guidelines
Assessment guidelines with examples
Estimating available heat energy
Selecting an appropriate calculation method
Selecting reasonable input parameters (in particular, distance
to arc and arc gap)
Tables for single-phase arc in open air
Selecting protective clothing and other protective
equipment
Appendix E to §1910.269 & Subpart V
Assessment Guidelines—
Sources
Sources of electric arcs
Unguarded, uninsulated live parts
Switches that arc in normal operation
Sliding parts subject to faults
Electric equipment subject to failure
Sources of flames
Open flames
Ignitible material near flames or arcs
Appendix E to §1910.269 & Subpart V
Assessment Guidelines—
Probability of Arc
Whether conductive objects can fall on live parts
Whether employee is inside MAD
Whether operation of electric equipment is part of
normal operation or occurs during servicing
Evidence of impending failure
Appendix E to §1910.269 & Subpart V
Assessment Examples
Task
Normal operation
Servicing and
maintenance
Exposure
Proper
maintenance and
no evidence of
impending failure
No
Evidence of arcing
or overheating
Yes
Evidence of
inadequate
maintenance
Yes
All
Yes
Assessment Examples
Task
Inspection with
exposed live parts
Exposure
Worker outside of
MAD and holding
no conductive
objects
No
Worker holding
conductive object
Yes
Worker inside MAD
Yes
Using open flames All
Yes
Guidelines for
Calculation Methods
Appendix E to §1910.269 & Subpart V
Notes on Calculation
Methods
Heat flux calculator
NFPA 70E Task Table
2012 edition
2015 edition
ARCPRO
v. 2.0
v. 2.01
Appendix E to §1910.269 & Subpart V
Guidelines on Arc Gap
Appendix E to §1910.269 & Subpart V
Appendix E IncidentEnergy Tables
Appendix E to §1910.269 & Subpart V
Arc-Rated Protection
Outer layer of clothing must be FR for incident
energy exceeding 2.0 cal/cm2
Arc-rated protection must cover entire body, with
certain exceptions:
Protection for hands (rubber gloves with protectors or, for
exposures ≤ 14 cal/cm2, heavy-duty (12-oz) leather work
gloves)
Protection for feet (heavy work shoes or boots)
Protection for the head under certain conditions
§1910.269(l)(8) & §1926.960(g)
Head and Face
Protection
Starts at 9 cal/cm2 for single-phase arcs in air
Starts at 5 cal/cm2 for other exposures
May be hard hat and face shield for these exposures:
< 13 cal/cm2 for single-phase arc in open air
< 9 cal/cm2 for other exposures
For open-air, single-phase arc exposures, the required
arc rating is reduced by 4 cal/cm2
§1910.269(l)(8) & §1926.960(g)
Compliance Deadlines
Incident energy estimates—January 1, 2015
Use FR clothing when incident energy exceeds 2.0
cal/cm2—April 1, 2015
Arc-flash protection—April 1, 2015
Everything else—July 10, 2014