Electrical Safety

In the laboratory, workers may be exposed to electrical hazards including electric shock, arc blasts, electrocutions, fires and explosions. Potential exposures to electrical hazards can result from faulty electrical equipment/instrumentation or wiring, damaged receptacles and connectors, or unsafe work practices. To avoid such hazards, follow these best practices:

• Always follow manufacturer’s recommendations for using electrical equipment. 
• Do not use electrical equipment to perform a task for which it is not designed. 
• Most equipment includes either a 3-pronged plug or double insulation. Equipment with neither of these features is less safe but may meet electrical codes. You will not be protected from electric shock if a 3-pronged plug is not inserted into a 3-prong outlet.  
• If you plug more than two pieces of low demand equipment into a standard outlet, use a fused power strip that will shut off if too much power is used. 
• Make sure that any outlet near a sink or other water source is Ground-Fault Circuit Interrupter (GFCI) protected. If you have a GFCI, periodically test it by plugging something into it and pushing the “test” button. Once the equipment shuts off just turn it back on. 
• Above all, do not disable any electrical safety feature. 
• Before turning equipment on, check that all power cords are in good condition. 
• Do not use extension cords as a substitute for permanent wiring. 
• If you see a person being electrocuted, DO NOT TOUCH THEM!  The electricity can go through you, too. If possible, turn off the power (pull the plug or trip the circuit breaker), or use an item made of non-conductive material (e.g., wooden broom handle) to pry the victim from the contact. Call 911 immediately. 

• High voltage equipment must be labeled: Danger, High Voltage. Switches to turn off all electrical power to the equipment in case of emergency should be prominently labeled. 
• Turn off the power to equipment before inspecting it. Turn off circuit breakers or unplug the equipment. To turn off a safety switch, use your left hand (wear insulating gloves made of leather or heavy cotton or rubber), turn your face away from the box, and pull the handle down. Circuits may discharge violently when being turned on or off and the cover to the junction box may be blown open.
• Use only tools and equipment with non-conducting handles when working with electrical devices.
• All current transmitting parts of any electrical devices must be enclosed.
• When checking an operating circuit, keep one hand either in a pocket or behind your back to avoid making a closed circuit through the body.
• Maintain a workspace clear of extraneous material such as books, papers, and clothes.
• Never change wiring with circuit plugged into power source.
• Never plug leads into power source unless they are connected to an established circuit.
• Avoid contacting circuits with wet hands or wet materials. 
• Wet cells should be placed on a piece of non-conducting material.
• Check circuits for proper grounding with respect to the power source.
• Do not insert another fuse of larger capacity if an instrument keeps blowing fuses - this is a symptom requiring expert repairs. If a fuse blows, find the cause of the problem before putting in another one.
• Do not use or store highly flammable solvents near electrical equipment.
• Multi-strip outlets (cube taps) should not be used in place of permanently installed receptacles. If additional outlets are required have them installed by an electrician.
• Keep access to electrical panels and disconnect switches clear and unobstructed. 

Sparks may result in explosions in areas where flammable liquids are being used and therefore proper grounding of equipment and containers is necessary. Some common potential sources of sparks are:

• The making and braking of an electrical circuit when the circuit is energized
• Metal tanks and containers
• Plastic lab aprons
• Metal clamps, nipples, or wire used with nonconducting hoses
• High-pressure gas cylinders upon discharge

Always be aware of surrounding personnel, equipment and materials to prevent inadvertent sparking.