PB 1.1-2007
Page 17
Section 10
MAINTENANCE
10.1 MAINTENANCE PROGRAM
A maintenance program for panelboards should be conducted on a regularly scheduled basis in accordance
with the following:
10.2 PANELBOARD WHICH HAS BEEN CARRYING ITS REGULAR LOAD FOR AT LEAST 3
HOURS
A panelboard which has been carrying its regular load for at least 3 hours just prior to inspection should be
field tested by feeling the deadfront surfaces of circuit breakers, switches, interior trims, doors, and
enclosure sides with the palm of the hand. If the temperature of these surfaces does not permit you to
maintain contact for at least 3 seconds, this may be an indication of trouble and investigation is necessary.
Thermographic (infrared) scanning has become a useful method of investigating thermal performance.
WARNING—HAZARDOUS VOLTAGES IN ELECTRICAL EQUIPMENT CAN CAUSE SEVERE
PERSONAL INJURY OR DEATH. UNLESS OTHERWISE SPECIFIED, INSPECTION AND
MAINTENANCE SHOULD ONLY BE PERFORMED ON PANELBOARDS TO WHICH POWER HAS
BEEN TURNED OFF, DISCONNECTED AND ELECTRICALLY ISOLATED SO THAT NO ACCIDENTAL
CONTACT CAN BE MADE WITH ENERGIZED PARTS. FOLLOW ALL MANUFACTURER’S
WARNINGS AND INSTRUCTIONS.
Safety related work practices, as described in NFPA 70E, should be followed at all times.
CAUTION—Hydrocarbon spray propellants and hydrocarbon based sprays or compounds will cause
degradation of certain plastics. Contact the panelboard manufacturer before using these products to clean,
dry, or lubricate panelboard components during installation or maintenance.
10.3 INSPECT PANELBOARD ONCE EACH YEAR
Inspect the panelboard once each year or after any severe short circuit.
10.4 ACCUMULATION OF DUST AND DIRT
If there is an accumulation of dust and dirt, clean out the panelboard by using a brush, vacuum cleaner, or
clean lint-free rags. Avoid blowing dust into circuit breakers or other components. Do not use a blower or
compressed air.
10.4.1 Visible Electrical Joints and Terminals
Carefully inspect all visible electrical joints and terminals in the bus and wiring system.
10.4.2 Conductors and Connections
Visually check all conductors and connections to be certain that they are clean and secure. Loose and/or
contaminated connections increase electrical resistance which can cause overheating. Such overheating is
indicated by discoloration or flaking of insulation and/or metal parts. Pitting or melting of connecting surfaces
is a sign of arcing due to a loose or otherwise poor connection. Parts which show evidence of overheating
or looseness should be cleaned and re-torqued or replaced if damaged. Tighten bolts and nuts at bus joints
to manufacturer’s torque specifications.
© Copyright 2007 by the National Electrical Manufacturers Association.
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