(1)
Application.
437-002-2314 provides for safe
work practices for high-voltage and high-power testing performed in
laboratories, shops, and substations, and in the field and on electric
transmission and distribution lines and equipment. It applies only to testing
involving interim measurements using high voltage, high power, or combinations
of high voltage and high power, and not to testing involving continuous
measurements as in routine metering, relaying, and normal line work.
Note to paragraph (1): Oregon OSHA considers
routine inspection and maintenance measurements made by qualified employees to
be routine line work not included in the scope of
437-002-2314, provided that the
hazards related to the use of intrinsic high-voltage or high-power sources
require only the normal precautions associated with routine work specified in
the other paragraphs of this rule. Two typical examples of such excluded test
work procedures are "phasing-out" testing and testing for a "no-voltage"
condition.
(2) General
requirements.
(a) The employer must establish
and enforce work practices for the protection of each worker from the hazards
of high-voltage or high-power testing at all test areas, temporary and
permanent. Such work practices must include, as a minimum, test area
safeguarding, grounding, the safe use of measuring and control circuits, and a
means providing for periodic safety checks of field test areas.
(b) The employer must ensure that each
employee, upon initial assignment to the test area, receives training in safe
work practices, with retraining provided as required by
437-002-2300(2).
(3) Safeguarding of
test areas.
(a)The employer must provide
safeguarding within test areas to control access to test equipment or to
apparatus under test that could become energized as part of the testing by
either direct or inductive coupling and to prevent accidental employee contact
with energized parts.
(b) The
employer must guard permanent test areas with walls, fences, or other barriers
designed to keep employees out of the test areas.
(c) In field testing, or at a temporary test
site not guarded by permanent fences and gates, the employer must ensure the
use of one of the following means to prevent employees without authorization
from entering:
(A) Distinctively colored
safety tape supported approximately waist high with safety signs attached to
it,
(B) A barrier or barricade
that limits access to the test area to a degree equivalent, physically and
visually, to the barricade specified in paragraph (3)(c)(A) of this rule, or
(C) One or more test observers
stationed so that they can monitor the entire area.
(d) The employer must ensure the removal of
the safeguards required by paragraph (3)(c) of this rule when employees no
longer need the protection afforded by the safeguards.
(4) Grounding practices.
(a) The employer must establish and implement
safe grounding practices for the test facility.
(A) The employer must maintain at ground
potential all conductive parts accessible to the test operator while the
equipment is operating at high voltage.
(B) Wherever ungrounded terminals of test
equipment or apparatus under test may be present, they must be treated as
energized until tests demonstrate that they are deenergized.
(b) The employer must ensure
either that visible grounds are applied automatically, or that employees using
properly insulated tools manually apply visible grounds, to the high-voltage
circuits after they are deenergized and before any employee performs work on
the circuit or on the item or apparatus under test. Common ground connections
must be solidly connected to the test equipment and the apparatus under test.
(c) In high-power testing, the
employer must provide an isolated ground-return conductor system designed to
prevent the intentional passage of current, with its attendant voltage rise,
from occurring in the ground grid or in the earth. However, the employer need
not provide an isolated ground-return conductor if the employer can demonstrate
that both of the following conditions exist:
(A) The employer cannot provide an isolated
ground-return conductor due to the distance of the test site from the electric
energy source, and
(B) The
employer protects employees from any hazardous step and touch potentials that
may develop during the test.
Note to paragraph (4)(c)(B): See Appendix C to
Division 2/RR for information on measures that employers can take to protect
employees from hazardous step and touch potentials.
(d) For tests in which using the
equipment grounding conductor in the equipment power cord to ground the test
equipment would result in greater hazards to test personnel or prevent the
taking of satisfactory measurements, the employer may use a ground clearly
indicated in the test set-up if the employer can demonstrate that this ground
affords protection for employees equivalent to the protection afforded by an
equipment grounding conductor in the power supply cord.
(e) The employer must ensure that, when any
employee enters the test area after equipment is deenergized, a ground is
placed on the high-voltage terminal and any other exposed terminals.
(A) Before any employee applies a direct
ground, the employer must discharge high capacitance equipment through a
resistor rated for the available energy.
(B) A direct ground must be applied to the
exposed terminals after the stored energy drops to a level at which it is safe
to do so.
(f) If the
employer uses a test trailer or test vehicle in field testing, its chassis must
be grounded. The employer must protect each employee against hazardous touch
potentials with respect to the vehicle, instrument panels, and other conductive
parts accessible to employees with bonding, insulation, or isolation.
(5) Control and
measuring circuits.
(a) The employer may not
run control wiring, meter connections, test leads, or cables from a test area
unless contained in a grounded metallic sheath and terminated in a grounded
metallic enclosure or unless the employer takes other precautions that it can
demonstrate will provide employees with equivalent safety.
(b) The employer must isolate meters and
other instruments with accessible terminals or parts from test personnel to
protect against hazards that could arise should such terminals and parts become
energized during testing. If the employer provides this isolation by locating
test equipment in metal compartments with viewing windows, the employer must
provide interlocks to interrupt the power supply when someone opens the
compartment cover.
(c) The
employer must protect temporary wiring and its connections against damage,
accidental interruptions, and other hazards. To the maximum extent possible,
the employer must keep signal, control, ground, and power cables separate from
each other.
(d) If any employee
will be present in the test area during testing, a test observer must be
present. The test observer must be capable of implementing the immediate
deenergizing of test circuits for safety purposes.
(6) Safety check.
(a) Safety practices governing employee work
at temporary or field test areas must provide, at the beginning of each series
of tests, for a routine safety check of such test areas.
(b) The test operator in charge must conduct
these routine safety checks before each series of tests and must verify at
least the following conditions:
(A) Barriers
and safeguards are in workable condition and placed properly to isolate
hazardous areas;
(B) System test
status signals, if used, are in operable condition;
(C) Clearly marked test-power disconnects are
readily available in an emergency;
(D) Ground connections are clearly
identifiable;
(E) Personal
protective equipment is provided and used as required by Division 2/I, Division
3/E, and Division 2/RR; and
(F)
Proper separation between signal, ground, and power cables.