b) Always assume that power is on until the true condition is determined.
Safety Practices. The following safety practices should be followed by all personnel
performing maintenance on lighted navigational aids:
a) Workers should be trained and familiar with electrical safety.
b) Safety rules should be strictly observed.
c) Commercial test equipment should be Underwriters Laboratory (UL) approved.
d) Prior to beginning any maintenance work on airport lighting circuits, coordinate
the work schedule with the tower, facility manager or public works personnel. Make sure
circuits will not be energized during maintenance, and obtain authorization for local control if
equipment is normally operated from a remote control point.
e) Where maintenance work is to be accomplished on a high-voltage circuit, at least
two electricians should be assigned, with one having a thorough knowledge of the layout of all
airport high-voltage circuits. The duties of the other electrician include:
(1) Keeping other personnel not involved in the work clear of the equipment.
(2) Being familiar with power disconnects and immediately disconnecting the
power source in case of emergency.
(3) Being qualified in first-aid and prepared to render emergency care if
necessary. The observer should bear in mind that prevention of an electrical accident is of
primary importance even though first-aid treatment is available.
(4) Observing the work being done to detect and warn against unsafe practices.
Personal Safety Precautions. The following commonsense safety precautions should
be standard procedure for every electrician:
a) Know the location of main power disconnect devices.
b) Know how to summon medical aid.
c) Remove necessary fuses to de-energize the circuit using properly insulated fuse
pullers. Consult circuit diagrams to identify all fuses involved. Remember that removal of a
fuse does not remove the voltage from the "hot" fuse clip. Discharge all capacitors.
d) Do not depend on interlocks to remove power or on indicating lights to signal that
power is off. Verify that voltage is off by using a voltmeter on the component after opening the