November 19, 2001
Mr. Edward M. Corcoran
EMC Code Consultants
12114 Country Lane
Burlington, WA 98233
Dear Mr. Corcoran:
Thank you for your May 24, 2001, letter to the Occupational Safety and Health
Administration's (OSHA's) Office of General Industry Compliance Assistance (GICA).
This letter constitutes OSHA's interpretation only with respect to the requirements discussed
and may not be applicable to any scenario not delineated within your original
correspondence. You made specific statements regarding your understanding of 29 CFR
1910.334(b)(2) and asked for our comments on your interpretation. Your statements have
been paraphrased into questions in this response.
1910.334(b)(2), Reclosing circuits after protective device operation. After
a circuit is de-energized by a circuit protective device, the circuit may not be manually
reenergized until it has been determined that the equipment and circuit can be safely
energized. The repetitive manual reclosing of circuit breakers or re-energizing circuits
through replaced fuses is prohibited.
Question 1: May unqualified personnel reset a circuit breaker or replace fuses
without having a qualified person investigate why the breaker tripped or the fuse blew?
Reply: Paragraph (b)(2) requires an evaluation to determine whether equipment and
circuits can be safely reenergized prior to operating a manual circuit protective device.
However, as the "Note" advises, if employees can verify an overload condition from the
de-energized circuit, then no examination is needed before the circuit is reenergized. In
this situation, an unqualified employee could reset the breaker or replace the fuse once, if
doing so would not expose the employee to electrical parts that are energized above 50 volts.
Question 2: Should an unqualified employee be allowed to reset a circuit breaker
more than once without determining the cause of the circuit malfunction?
Reply: If the breaker referenced in question #1 tripped again, then the circuit and/or
equipment must be examined and repaired by a qualified person before it could be reenergized.
Paragraph (b)(2) prohibits the repetitive manual reclosing of circuit breakers or reenergizing circuits
through replacement fuses.
Question 3: Are equipment operators and foremen considered electrically
unqualified to evaluate and reset circuit breakers?
Reply: According to subsection 1910.332(a), employees exposed to electric shock
or other electrical hazards that are not reduced to a safe level by the electrical installation
requirements of sections 1910.303 - 308 must be trained in the electrical safety-related
work practices contained in sections 1910.331 - 335. Paragraph 1910.333(c)(2) states
that only qualified persons may work on electric circuit parts or equipment that has not
been de-energized under the lockout/tagout provisions of subsection 1910.333(b).
Additionally, paragraph 1910.334(c)(1) stipulates that only qualified persons, i.e., those
familiar with the construction and operation of the equipment and the hazards involved,
may perform testing work on electric circuits or equipment.
Therefore, qualified persons must have electrical-related training sufficient to effectively
avoid the electrical hazards associated with work on, or near, exposed energized parts.
These qualified persons must be capable of working safely on energized circuits. This
capability includes familiarity with the proper use of: special precautionary techniques,
personal protective equipment, insulating or shielding materials, and insulated tools.
The operator or foreman would have to meet the qualifications referenced above (and fully
detailed in Subpart S) before examining or troubleshooting a circuit that is energized above 50 volts.
Question 4: Are operators and foremen allowed to reset circuit breakers where the
operator or foreman must open a piece of electrical equipment and become exposed to
parts energized above 50 volts?
Reply: See reply to Question 3.
Question 5: Would resetting circuit breakers with the manufacturer's metal
enclosure door opened on 480-volt equipment be allowed if the exposed energized
parts are covered by a plexiglass barrier as a substitute for the protection normally
afforded by the metal enclosure when the breaker is tripped?
Reply: Employees may only use electrical equipment that has been tested and
determined to be safe for use in a specified configuration by a nationally recognized
testing laboratory (NRTL). The electrical equipment must be used in accordance
with the manufacturer's instructions or any instructions included with the listing or
labeling. Therefore, the only approved use of the referenced enclosure would be
that prescribed by the manufacturer whose instructions must concur with NRTL test
results, i.e., metal door attached and in its operating position during breaker manipulations.
Thank you for your interest in occupational safety
and health. We hope you find this information helpful.
OSHA requirements are set by statute, standards and regulations.
Our interpretation letters explain these requirements and how they
apply to particular circumstances, but they cannot create
additional employer obligations. This letter constitutes OSHA's
interpretation of the requirements discussed. Note that our
enforcement guidance may be affected by changes to OSHA rules.
Also, from time to time we update our guidance in response to
new information. To keep appraised of such developments, you
can consult OSHA's website at http://www.osha.gov.
If you have any further questions, please feel free to contact the
Office of General Industry Compliance Assistance at (202) 693-1850.
Note: When it can be determined from the design of the circuit and the over
current devices involved that the automatic operation of a device was caused
by an overload rather than a fault condition, no examination of the circuit or
connected equipment is needed before the circuit is reenergized.
Richard E. Fairfax, Director
Directorate of Compliance Programs