Title: Electrical Safe Work Practice
1Electrical Safe Work Practice
2Standard Outline
- .331 Scope
- .332 Training
- .333 LOTO MADs Safe Work Practices
- .334 Use of Equipment Portable, Fixed, Test
- .335 PPE and Warning
3- Based in part on NFPA 70 E
4Premises Wiring
- Installations of electric conductors and
equipment within or on buildings or other
structures, and on other premises such as yards,
carnival, parking, and other lots, and industrial
substations
5Equipment
- A general term including material, fittings,
devices, appliances, fixtures, apparatus, and the
like, used as a part of, or in connection with,
an electrical installation.
6Qualified Person
- One familiar with the construction and operation
of the equipment and the hazards involved.
7Qualified Person
- If their work exposes them to electrical hazards
which would otherwise be protected according to
Subpart S They must protect themselves against
ALL the electrical hazards. - Hazards include Shocks, Electrocution, Arc
Blast, Burns, Explosions.
8Unqualified Person
- Normally protected by Subpart S.
- However
- If their work exposes them to electrical hazards
which would otherwise be protected according to
Subpart S They must be trained.
9.332(a)Training
- Employees who face a risk of electric shock that
is not reduced to a safe level by the electrical
installation requirements of 1910.303 through
1910.308.
10.332(b)(2)Training
- Employees who are covered by paragraph (a) of
this section but who are not qualified persons
shall also be trained in and familiar with any
electrically related safety practices not
specifically addressed by 1910.331 through
1910.335 but which are necessary for their
safety.
11.333 Work Practices
- Live parts (50 Volts or more) shall be
de-energized before working on them. - Unless the employer can demonstrate infeasibility
or greater hazard.
12.333Work Practices
- Written procedure.
- De-energize equipment release stored energy.
- Apply locks tags.
- Verify de-energization test.
- Re-energize.
13.333Work Practices
- Capable of working live familiar with
techniques, PPE Insulating, shielding
materials, insulated tools. - Overhead lines MADs.
- Adequate illumination no blind reaching.
- Shielding provided for enclosed spaces.
14Tools
Rated insulated tool . Tool should be marked
with rating.
- Non-Rated tool with cushioned grip.
15Insulated Tools
16.333Work Practices
- No conductive materials or equipment.
- Nonconductive ladders.
- No conductive apparel.
- Housekeeping no steel wool or conductive
liquids.
17.334(a) Use of Portable Equipment
- Covers cordsets (extension cords).
- Cord Plug connected equipment.
- For qualified unqualified workers.
18.334(a) Use of Portable Equipment
- Dont abuse, damage, or use for a rope. (a)(1)
- Visually inspect before use. (a)(2)
- Shall be removed from service not used until
repaired. (a)(2)(ii)
19.334(a) Use of Portable Equipment
- Extension cords shall be grounded unless used
with double insulated tools. (a)(3)(i) - Dont mess with the grounding pin. (a)(3)(ii)
- No 3-wire grounding adapters, unless the ground
continuity is maintained. (a)(3)(iii)
20.334(a) Use of Portable Equipment
- Damp/Wet locations require equipment approved for
same. (a)(4) see .303(b)(2) - Dont plug in or unplug stuff with wet hands.
(a)(5) - Twist lock connectors must be locked before use.
(a)(5)(iii)
21.334(c)Test Equipment
- Test instruments used only by qualified
employees. - Visually inspected before use, including leads
and probes. - Rating of equipment (voltage)
- Test leads rated for full voltage.
- Designed for environment.
22.335Protective Equipment
- Employees working in areas where they are no
potential electrical hazards shall use
electrical PPE. - PPE 1910.132 - 1910.138.
- Electrical Protective Equipment ASTM F
Standards. - Textile Clothing NFPA 70E ASTM F1506.
231910.137(b) In-service Care and Use
- Maximum use voltage to conform to Table I-5.
- Equipment damage inspection
- No holes, tears, cuts, or punctures no ozone
cutting or checking no embedded foreign objects
no swelling, softening, hardening, etc.
241910.137(b)(2)(ii)Air Testing of Rubber Gloves
251910.137(b)(2)(viii) Rubber Insulating
Equipment Test Intervals
26Electric Arc Hazards
- Electric Arcs can reach temperatures of 34,000oF
- The arcs can vaporize metal, burn skin, and
ignite clothing. - Vaporized copper expands 67,000 times in volume.
- High pressures can develop in enclosures, causing
covers and molten metal to fly.
27Arc Hazards
- When clothing ignites, it can greatly increase
the amount of skin area burned, and the chance of
a fatality. - Heat levels of 1.2 cal/cm2 per second for one
second can cause second degree burns to exposed
skin. - Most arc exposure times are less than 1 second.
28Arc Hazards
- Regular cotton work clothing will typically not
ignite at heat levels up to 1-2 cal/cm2. - Heavy denim might work for about 5-10 cal/cm2.
29Arc Heat Example
- 480 Volt arc in a box. 6 cycles, at a 12 inch
distance. - 16,000A 8 - 11 cal/cm2
- 24,000A 9 14 cal/cm2
- 38,000A 17 24 cal/cm2
- 50,000A 32 38 cal/cm2
30Available Fault Current Example
31.335(a)(1)Protective Equipment
- Maintain periodically test according to .137.
- Protect the insulating capability against damage.
- Nonconductive head protection.
- Face Eye Protection for arc blast.
32.335(a)(2)Protective Equipment
- Shall use insulated tools and handling equipment
(ASTM 1505 specifications). - Fuse pullers.
- Nonconductive rope.
- Protective shields barriers.
33.335(b)Alerting Techniques
- Signs
- Barricades
- Attendants
34Thank You For Your Interest in Job Safety
Health.