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SAFETY MODEL STAGE 3—CONTrOLLING HAZArDS: SAFE WOrK ENVIrONMENT

Control hazards of fixed wiring

The wiring methods and size of conductors used in a system depend on several factors:

Intended use of the circuit system

Building materials

Size and distribution of electrical load

Location of equipment (such as underground burial)

Environmental conditions (such as dampness)

Presence of corrosives

Temperature extremes

fixed wiring—the permanent wiring installed in homes and other buildings

Fixed, permanent wiring is better than extension cords, which can be misused and damaged more easily. NEC requirements for fixed wir- ing should always be followed. A variety of materials can be used in wiring applications, including nonmetallic sheathed cable (Romex®), armored cable, and metal and plastic conduit. The choice of wiring material depends on the wiring environment and the need to support and protect wires.

Aluminum wire and connections should be handled with special care. Connections made with aluminum wire can loosen due to heat expansion and oxidize if they are not made properly. Loose or oxidized connections can create heat or arcing. Special clamps and terminals are necessary to make proper connections using aluminum wire. Antioxidant paste can be applied to connections to prevent oxidation.

Control hazards of flexible wiring

Use flexible wiring properly

Electrical cords supplement fixed wiring by providing the flexibility required for maintenance, portability, isolation from vibration, and emergency and temporary power needs.

Nonmetallic sheathing helps pro- tect wires from damage.

Page 42

Section 7

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