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SAFETY MODEL STAGE 3—CONTrOLLING HAZArDS: SAFE WOrK ENVIrONMENT

5 times the diameter of the cable so that insulation at a bend is not damaged. Extension cords come with insulation in a variety of types and colors. The insulation of extension cords is especially important. Since extension cords often receive rough handling, the insulation can be damaged. Extension cords might be used in wet places, so adequate insulation is necessary to prevent shocks. Because exten- sion cords are often used near combustible materials (such as wood shavings and sawdust), a short in an extension cord could easily cause arcing and a fire.

Arc-fault circuit breaker.

Insulation on individual wires is often color-coded. In general, insu- lated wires used as equipment grounding conductors are either con- tinuous green or green with yellow stripes. The grounded conductors that complete a circuit are generally covered with continuous white or gray insulation. The ungrounded conductors, or “hot” wires, may be any color other than green, white, or gray. They are usually black or red.

Conductors and cables must be marked by the manufacturer to show the following:

maximum voltage capacity,

AWG size,

insulation-type letter, and

the manufacturer’s name or trademark.

Control hazards of shocking currents

Ground circuits and equipment

When an electrical system is not grounded properly, a hazard exists. This is because the parts of an electrical wiring system that a person normally touches may be energized, or live, relative to ground. Parts like switch plates, wiring boxes, conduit, cabinets, and lights need to be at 0 volts relative to ground. If the system is grounded improper- ly, these parts may be energized. The metal housings of equipment plugged into an outlet need to be grounded through the plug.

Ground electrical devices.

Page 48

Section 7

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