06 Jul Electrical Equipment Guarding and Workspaces
Electrical Equipment Guarding and Workspaces
Electrical equipment such as panels, switchboards, transformers, disconnects, and junction boxes can expose workers to serious electrical hazards. Contact with energized parts can cause shock, burns, arc-flash injuries, falls, or electrocution. Proper guarding and adequate working space help prevent accidental contact and allow qualified employees to work safely.
Electrical Shock Hazards
Electrical shock occurs when the body becomes part of an electrical circuit. The severity of an injury depends on several factors, including the amount of current, its path through the body, and the duration of contact.
Even relatively low voltages can cause serious injury. Electrical shock can also cause involuntary muscle reactions or startle a worker, resulting in a secondary injury such as a fall from a ladder or elevated work surface.
Guarding Energized Parts
Live electrical parts operating at 50 volts or more must be guarded against accidental contact by approved cabinets, enclosures, partitions, screens, location, or other suitable means.
Workers should:
- Keep electrical covers, doors, guards, and barriers securely in place.
- Never remove guards or expose energized components unless authorized and qualified to perform the work.
- Restrict access to rooms or enclosures containing exposed energized parts to qualified personnel.
- Observe electrical hazard signs, labels, and warnings.
- Never reach into electrical cabinets or enclosures unless qualified and authorized.
- Treat electrical equipment as energized until it has been properly de-energized and verified safe.
Electrical equipment should be clearly marked as required to identify applicable voltage, current, wattage, or other electrical characteristics.
Electrical Equipment Conditions
Electrical equipment should be installed and maintained to prevent exposure to conditions that could create additional hazards.
- Keep electrical equipment as dry as practicable and protect it from damaging moisture, chemicals, excessive heat, and physical damage.
- Keep ventilation openings clear to prevent overheating.
- Securely mount equipment to the surface for which it was designed.
- Maintain covers and enclosures over components that could arc, spark, or otherwise create an ignition hazard.
- Do not block electrical panels, disconnects, or emergency controls.
Damaged or defective electrical equipment must be reported and removed from service when necessary until properly repaired.
Working Space and Clearance
Sufficient access and working space must be maintained around electrical equipment to permit safe operation and maintenance.
For equipment operating at 600 volts nominal or less, OSHA working-space requirements vary according to the nominal voltage to ground and the conditions opposite the exposed live parts.
| Nominal Voltage to Ground | Condition 1* | Condition 2** | Condition 3*** | ||
|---|---|---|---|---|---|
| 0–150 volts | 3 ft. | ||||
| 3 ft. | 3 ft. | ||||
| 3.5 ft. | 4 ft. |
* Condition 1: Exposed live parts on one side and no live or grounded parts on the other side, or exposed live parts effectively guarded by insulating materials.
** Condition 2: Exposed live parts on one side and grounded parts on the other side. Concrete, brick, and tile walls are considered grounded.
*** Condition 3: Exposed live parts on both sides of the working space.
These distances are minimum requirements. Additional clearance may be necessary depending on the equipment, installation, voltage, or applicable electrical standard.
Keep Electrical Workspaces Clear
Required electrical working space must not be used for storage.
Never place tools, materials, boxes, ladders, equipment, combustible materials, or other objects where they block access to electrical panels or interfere with the required working clearance.
Electrical workspaces must also:
- Have adequate illumination.
- Provide safe access and sufficient space for workers to perform required tasks.
- Maintain required headroom.
- Have entrances and exits appropriate for the electrical equipment and hazards involved.
- Remain free of trip hazards and unnecessary obstructions.
When normally enclosed energized parts are exposed for inspection or servicing, the work area must be appropriately guarded to prevent unqualified persons from entering or contacting energized parts.
Before Electrical Work Begins
Only qualified employees may perform work on exposed energized electrical parts. Whenever possible, electrical equipment must be de-energized before work begins.
When servicing equipment:
- Identify all electrical energy sources.
- De-energize the equipment.
- Apply required lockout/tagout procedures.
- Verify that the equipment has been de-energized before beginning work.
- Use appropriate electrical PPE, tools, and safe work practices for the task.
- Restore guards, covers, and barriers before returning equipment to normal service.
Remember
Electrical panels and equipment require more than just a cover. They need proper guarding, adequate clearance, unrestricted access, sufficient lighting, and protection from damaging conditions.
Never use the required electrical working space for storage, and never remove electrical guards or covers unless you are qualified and authorized to do so.