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615 Electrical Safety - Hazards and Controls
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Control Inadequate Wiring Hazards

Electrical hazards result from using the wrong size or type of wire. You must control such hazards to create a safe work environment.

Two workers cabling fixed electrical wiring
These workers are cabling fixed electrical wiring.

You must choose the right size wire for the current expected in a circuit. The wire must be able to handle the current safely. The wire's insulation must be appropriate for the voltage and tough enough for the environment. Connections need to be reliable and protected.

Fixed, permanent wiring is better than extension cords, which can be misused and damaged more easily. A variety of materials can be used in wiring applications, including non-metallic sheathed cable (Romex®), armored cable, and metal and plastic conduit.

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

Control Hazards of Flexible Wiring

Flexible wiring can be used for extension cords or power supply cords. DO NOT use flexible wiring as a substitute for fixed wiring or in situations where:

  • frequent inspection would be difficult,
  • damage would be likely, or
  • long-term electrical supply is needed.

Flexible cords must not be:

  • run through or hidden in holes in walls, ceilings, or floors;
  • run through doorways, windows, or similar openings (unless physically protected); or
  • attached to building surfaces (except with a tension take-up device within 6 feet of the supply end)

Knowledge Check Choose the best answer for the question.

3-5. Do not use flexible wiring as a substitute for fixed wiring or in situations where _____.