PREPARE THE SITE
De-energize equipment during repairs or inspection.
Assume a safe position near energized equipment.
Use safe tools or equipment.
Only individuals qualified by training or experience should maintain electric or electronic equipment.
Electric wires should never be used as supports. Live wires should not be pulled.
Any electrical failure or any evidence of undue heating of equipment should be reported immediately to the instructor.     
All electrical installations should adhere to the standards of the National Electric code.
Wiring that is frayed or worn should be eliminated.
All extension cords must be UL listed and sufficiently rated for the intended load. Extension cords are for temporary use only.
Cords shall not be stretched across the floor where they would create a tripping hazard.
Nothing may be stored within 3' of an electrical box.
All electrical panels and switch gear must be unobstructed.
Circuit breakers should be labeled properly. Tape shall not be used to secure any breaker in either an off or on position.
All electrical plugs shall have a three pronged plug. 
During servicing, all equipment should be 'locked-out' to avoid accidental activation, and 'tagged-out' with the purpose of the servicing and the name of the person working.

Electrical currents of very low amperage and voltage under certain circumstances may result in fatal shock.  Voltages as low as 24 volts ac can be dangerous and present a lethal threat.

Low voltage DC circuits do not normally present a hazard to human life, although severe burns are possible.  The time of contact with a live circuit affects the degree of damage.
Recommendations for minimizing electrical hazards follow:
All electrical equipment should be periodically inspected to be certain the cords and plugs are in a safe condition and that only three wire, grounded, double insulated or isolated wiring is used in 110v-115v applications.
DURING THE EXPERIMENT
  Always assume that all circuits are energized.
  Never grasp electrical equipment.  Whenever possible, use only one hand when working near energized electrical equipment.
  Electrical outlets and connections should not be in the vicinity of wet operations.  Ground Fault Interrupters should be installed in areas where water may accidentally contact electrical connections.
  All personnel should know the location of circuit breakers and be able to cut off the electrical service in the case of a fire or accident.
  Do not use conductive materials such as wires, tools, metal ladders, etc. around energized conductors or parts of equipment. Avoid wearing metallic jewelry when working on electrical equipment.
  Do not leave energized electrical equipment exposed and unattended. Use suitable barricades and signs to prevent access to energized equipment.