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8.3 Serviceman servicing
8.3.1 An electrical component that may require adjustment, servicing, or maintenance not specified in the
operator’s manual shall be located and mounted with respect to other components and with respect to
grounded metal parts so that it is accessible for electrical service functions without subjecting the
serviceman to the likelihood of electric shock or injury to persons. Access to components for servicing
shall not be impeded by other components or by wiring in the direction of access.
8.3.2 The electrical components mentioned in 8.3.1 include a fuse and an adjustable control.
8.3.3 All conductive internal parts that are accessible to service personnel and that are usually expected
to be at ground potential (heatsinks and the like), but are energized and involve a risk of electric shock,
shall be marked in accordance with 57.23.
8.3.3 revised October 15, 2004
9 Assembly
9.1 An uninsulated live part shall be secured to the base or surface so that it will be prevented from
rotating or shifting in position as the result of normal stresses if such movement might result in a reduction
of spacings below the minimum acceptable values. See Section 28, Spacings.
9.2 A component such as a rectifier element, control switch, lampholder, attachment plug receptacle, or
plug connector shall be mounted securely and shall be prevented from turning by means other than
friction between surfaces.
Exception No. 1: A switch, if the following conditions are met:
a) The switch is a plunger or other type that does not tend to rotate when operated–a toggle
switch is considered to be subject to forces that tend to turn the switch;
b) The means for mounting the switch makes it unlikely that operation of the switch will loosen
it;
c) Spacings are not reduced below the minimum acceptable values if the switch rotates; and
d) Normal operation of the switch is by mechanical means rather than by direct contact by
persons.
Exception No. 2: A lampholder of the type in which the lamp cannot be replaced, such as a sealed neon
pilot or indicator light, if rotation cannot reduce spacings below the minimum acceptable value.
9.3 A small stem-mounted device having a single-hole mounting means may be prevented from rotating
by a lock washer properly applied.
9.4 If a switch or circuit breaker is mounted such that movement of the operating handle, either linearly
or rotationally, between the on and off positions results in one position being above the other position, then
the upper position shall be the on position. This requirement does not apply to a switching device having
two on positions such as a double throw switch.
OCTOBER 15, 2004UL 45820
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