Most electrical accidents result from one or more of the following factors:
| Factors Contributing to Electrical Accidents |
|---|
| Unsafe equipment or installation |
| Unsafe environment |
| Unsafe work practices |
To prevent these accidents, it is critical to protect against unsafe equipment, environments, and work practices. Common protective measures include:
- Insulation
- Guarding
- Grounding
- Electrical protective devices
- Safe work practices
Insulation
Insulation materials such as glass, mica, rubber, or plastic coat metals and other conductors to prevent or reduce electrical current flow. This helps to avoid electrical shocks, fires, and short circuits.
- Insulation must be suitable for the voltage level and environmental conditions.
- Environmental factors that may degrade insulation include temperature, moisture, oil, gasoline, and corrosive fumes.
Types of Insulation
- Color Coding:
- Grounding insulation: solid green or green with yellow stripes
- Grounded conductors: white or gray insulation
- Ungrounded (hot) conductors: typically black or red, but can be any color except green, white, or gray
- Inspection:
- Check insulation for exposed wires or damage before connecting equipment to power.
- Flexible cords (e.g., extension cords) are especially vulnerable to damage.
Regulatory Requirements
- Non-construction settings:
- Governed by 29 CFR 1910.302 – 1910.308, Wiring Design and Protection
- Requires insulation on circuit conductors suitable for voltage and environmental conditions
- Construction settings:
- Governed by 29 CFR 1926.402 – 1926.408