All laboratory instruments and electrical appliances must be grounded and checked for current leakage before initial use, after repair or modification, and when a problem is suspected.
OSHA allows these exceptions to the above requirements:
- Devices protected by an approved system of double insulation don't need to be checked for current leakage.
- These devices must be clearly marked as "double-insulated."
- Devices connected to wall receptacles or circuit breakers with ground-fault circuit interrupter (GFCI) protection built in don't need to be checked for current leakage.
- GFCI must be utilized in areas where water may pose an added risk.
- Equipment operating at 240 V must be checked for ground integrity only.
Verification of electrical safety is required whenever the electrical/electronic systems of a powered device has been removed or altered. OSHA requires that power cords of portable electrical equipment be visually inspected for external defects whenever relocated.
Periodic checks should be made on all electrical wires. Frayed cords are the most common cause of laboratory fires. If frayed cords or wires are found, the equipment should be immediately removed from use and repaired.
Report to your supervisor any shocks or tingling received from electrical equipment.