An adequate number of receptacles should be provided at the laboratory bench to remove the need for extension cords and long lengths of cords. Receptacles that provide electric power for operation in hoods should be located outside of the hood. This location prevents the production of electrical sparks inside the hood. Circuits should not be overloaded by using multiple sockets and extension cords. Although much safer than Bunsen burners, these devices pose electrical and fire hazards if used improperly.
Variable transformers control the temperature on many laboratory heating devices.
Because some sparking may occur when the control knob is turned, transformers should be located where they will not be exposed to flammable liquids or vapors. Connections from the variable transformer to the heating device should not be done with alligator clips because of the potential shock and spark hazard. Heating devices left unattended overnight should be equipped with a device that turns the power off if a preset temperature is exceeded. The heating element in any laboratory heating device should be enclosed in an insulated case that prevents contact with the worker and protects against sparks. Laboratory hot plates.