Joshua Maestas, OHST
Presented to DIOSH Day on 3/2/16
Joshua Maestas
Safety & Technical
Instructor and Consultant
(808)554-4743
jpmaestas@lpmgmtservices.com
http://www.lpmgmtservices.com
• An arc is an electric discharge that travels through the air
either:
– between conductors
or
– from a conductor to a ground
• An arc FLASH is an undesirable electric discharge that travels
through the air either:
– between conductors
or
– from a conductor to a ground
• Dust, impurities, corrosion, condensation
• Contamination or Tracking over insulation
• Spark discharge from:
– Accidental touching
– Dropping un-insulated tools
• Over-Voltages across narrow gaps
– Using a low voltage meter on MV equipment
• Failure of insulating materials
• Equipment Failure
• Critters
• Incident energy  Total Energy Released during an event
𝑈𝑈𝑈𝑈𝑈 𝑜𝑜 𝐸𝐸𝐸𝐸𝐸𝐸
𝑆𝑆𝑆𝑆𝑆𝑆𝑆 𝐴𝐴𝐴𝐴
⇒
𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐
𝑗𝑗𝑗𝑗𝑗𝑗
𝑜𝑜
2
2
𝑐𝑐
𝑐𝑐
• The amount of heat required at a pressure of one atmosphere
to raise the temperature of 1 gram of water 10 C.
or…
= 1 calorie
Held for 2 Seconds
Molten Metal
Extremely High Temps
15,000- 35,000 °F
Pressure Waves
200 lbs/sq inch
Sound Waves
135+ decibels at 2ft
Shrapnel
@700 mph
Copper Vapor:
Solid to Vapor
Expands by
67,000 times
8
Intense Light
• Case 1: Not knowing your equipment
• Case 2: Not following the rules
• Type and location of short circuit
– Arcs inside an enclosure can be 2-12X worse than the same
open-air arc.
• Distance of the Worker or Observer
• Source of Power and System Configuration (Amount of
Current Available)
• Trip time of available circuit protective devices
• Type of PPE worn
• Inhaling high
temperature copper
vapor.
• Scarring of the lungs
can lead to
pneumonia
• More than 100 toxic
substances can be
found in electrical
fumes.
IE in
Cal/cm2
204
150
100
75
No Safe PPE
40
AFB
1.2
Working
Distance
12
18 36
?72
X2 X4
235
Distance in
Inches
Personal Protective Category 1
1.2 cal/cm2 4 cal/cm2
•
•
•
•
•
•
•
•
Arc-rated long-sleeve shirt and pants or arc-rated coverall
Arc-rated face shield or arc flash suit hood
Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
Hard hat
Safety glasses or safety goggles (SR)
Hearing protection (ear canal inserts)
Heavy duty leather gloves
Leather footwear (AN)
Personal Protective Category 2
4 cal/cm2 8 cal/cm2
• Arc-rated long-sleeve shirt and pants or arc-rated coverall
• Arc-rated flash suit hood or arc-rated face shield and arcrated balaclava
• Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
• Hard hat
• Safety glasses or safety goggles (SR)
• Hearing protection (ear canal inserts)
• Heavy duty leather gloves
• Leather footwear
Personal Protective Category 3
8 cal/cm2 25 cal/cm2
•
•
•
•
•
•
•
•
•
•
•
•
Arc-rated long-sleeve shirt (AR)
Arc-rated pants (AR)
Arc-rated coverall (AR)
Arc-rated arc flash suit jacket (AR)
Arc-rated arc flash suit pants (AR)
Arc-rated arc flash suit hood
Arc-rated gloves
Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
Hard hat
Safety glasses or safety goggles (SR)
Hearing protection (ear canal inserts)
Leather footwear
Personal Protective Category 4
25 cal/cm2 40 cal/cm2
•
•
•
•
•
•
•
•
•
•
•
•
Arc-rated long-sleeve shirt (AR)
Arc-rated pants (AR)
Arc-rated coverall (AR)
Arc-rated arc flash suit jacket (AR)
Arc-rated arc flash suit pants (AR)
Arc-rated arc flash suit hood
Arc-rated gloves
Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
Hard hat
Safety glasses or safety goggles (SR)
Hearing protection (ear canal inserts)
Leather footwear
Dangerous
>40 cal/cm2
• No Safe PPE Exists
• The following steps will minimize risk to personnel and
equipment while performing switching:
– Secure authorization before performing any switching, preferably in
writing as part of a MOP.
– Review one-line diagram to identify all equipment affected by
operation.
– Perform a system walkthrough to verify diagrams and identify
location specific hazards.
• The following steps will minimize risk to personnel and equipment
while performing switching:
– Devices used to open circuits under load conditions must be designed to
interrupt the current involved.
– Personal protective equipment shall be worn as determined by a flash
hazard analysis or as required by the Tables in the Electrical Safety Policy.
– Identify the immediate blast zone. If the switch fails, where will the blast
go?
– If you cannot operate the device remotely, stand off to the side that offers
the most protection from an anticipated blast.
• The following steps will minimize risk to personnel and
equipment while performing switching:
– Notify all personnel affected by the switching operation.
– Unload the circuit, if practical.
– Keep all others out of the area.
– Make sure panel covers and doors are secure.
– Do not reach across the panel door, if avoidable.
• The following steps will minimize risk to personnel and
equipment while performing switching:
– Take a deep breath and hold it.
– Once the worker is prepared to operate the switch, it should be
operated as if it may fail.
– Before re-energizing, verify that all locks, blocks and tags have been
removed and a qualified person has tested the circuit safe to reenergize