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15.3 Protection of wiring
15.3.1 Internal wiring shall be protected if, when judged in accordance with 8.1.2, it is accessible.
Exception: Internal wiring need not be protected if it is located and secured within the enclosure so that
it is not likely to be subjected to stress or mechanical damage.
15.3.2 Wires within an enclosure, compartment, raceway, or the like shall be located or protected to
prevent contact with any sharp edge, burr, fin, moving part, or the like that can damage the conductor
insulation.
15.3.3 A hole through which insulated wires pass in a sheet metal wall within the overall enclosure of a
converter or inverter shall be provided with smooth, rounded surfaces upon which the wires may bear, to
prevent abrasion of the insulation.
15.3.3 effective April 13, 1993
15.3.4 Internal wiring within an enclosure or compartment shall be located or protected from surfaces so
that the temperature rating of the conductors will not be exceeded under normal operating conditions.
15.3.5 Mounting screws and nuts shall be designed or located so that sharp edges will not damage
wiring. A screw shall have a flat or blunt end. The end of the screw shall not have burrs, fins, or sharp
edges that might abrade wire insulation, and shall not project more than 3/16 inch (4.8 mm) into a
wireway.
15.4 Electrical connections
15.4.1 Aluminum conductors, insulated or uninsulated, used as internal wiring, such as for
interconnection between current-carrying parts or in a component winding, shall be terminated at each
end by a method suitable for the combination of metals involved at the points of connection.
15.4.2 With reference to 15.4.1, a wire-binding screw or a pressure wire connector used as a terminating
device shall be suitable for use with aluminum under the conditions involved, for example, temperature,
heat cycling, vibration, and the like.
15.4.3 All splices and connections shall be mechanically secure and shall make reliable electrical contact.
15.4.4 A soldered connection shall be mechanically secured before being soldered.
Exception: A wave- or lap-solder connection to a printed-circuit board where components are properly
inserted or secured (as in a surface mounted component) is considered acceptable without any further
mechanical security.
15.4.4 revised October 15, 2004
15.4.5 A splice shall be provided with insulation equivalent to that of the wires involved if permanent
spacing may not be maintained between the splice and other metal parts.
OCTOBER 15, 2004 UL 458 29
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