Electrical hazards are present in all laboratories. Adherence to all electrical safety standards is essential in preventing electrical accidents

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Electrical hazards are present in all
laboratories. Adherence to all electrical safety
standards is essential in preventing electrical
accidents
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a complete circuit or loop is necessary for
current to flow
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Electricity in the body

• Muscles
• Muscles control all the body movements
• Including importantly those that keep us alive
  - Breathing and Heart
• The brain controls voluntary muscles using
  Current pulses along nerves

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Electricity in the body

• External current through the body causes
• Loss of muscle control
• Spasms Involuntary movement
• Inability to let go
• Burns - external internal

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• The severity and effects of an electrical
  shock depend on a number of factors,
• such as
• The pathway through the body
• The amount of current
• The length of time of the exposure
• Whether the skin is wet or dry.

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Physiological Effects of Electricity
Current Reaction
1-5 Milliampere Slight shock felt not painful but disturbing
6-30 Milliamperes Painful shock "let-go" range
50-150 Milliampere Extreme pain, respiratory arrest, severe muscular contraction
1,000-4,300 Milliamperes Ventricular fibrillation
10,000 Milliamperes Cardiac arrest, severe burns, and probable death
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Electrical Hazards

• Major hazards associated with electricity are
  electrical shock and fire.
• Electrical shock occurs when the body becomes
  part of the electric circuit , when
• An individual comes in contact with both wires of
  an electrical circuit.
• One wire of an energized circuit and the ground.
• Or a metallic part that has become energized by
  contact with an electrical conductor.

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• In addition to the electrical shock hazards,
  sparks from electrical equipment can serve as an
  ignition source for flammable or explosive
  vapors.
• Loss of electrical power can result in
  extremely hazardous situations
• Flammable or toxic vapors may be released as a
  chemical warms when a refrigerator or freezer
  fails.
• Fume hoods may cease to operate, allowing vapors
  to be released into the laboratory.

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Common Electrical Problems

• Extension Cords and Power Strips
• Power Cords
• Solvents and Electricity
• Water and Electricity
• Laboratory Equipment
• Capacitors and Transformers

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Power strips are approved for use only with
computers and computerized equipment. Power
strips should be used sparingly. Care must be
taken not to overload power strips.
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extension cords are approved for temporary use
only. if extended use is required, hard wiring
such as a new outlet should be installed.
extension cords are easily frayed, a condition
which may expose bare wires.
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Power cords are doubly insulated and should be
replaced if the outer layer of insulation becomes
frayed exposing wires.
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Power Cords
Avoid dangling cords and cords at floor.
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Overloads occur when more current flows through a
cord than it is rated to handle. Power strips
can be overloaded if too many high current draw
devices are plugged in at one time
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Common laboratory equipment such as centrifuges
and ovens are high current draw devices. If two
or more high current draw devices are plugged
into the same outlet or power strip an overloaded
circuit may result.
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Care must be taken to insure that power cords do
not come in contact with hot surfaces such as the
top of a hot plate where they may melt exposing
bare wires.
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Power strips must be located outside of any fume
hood where flammable vapors are present.
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Water and Electricity

• Eyewashes should be located away from
  electrical devices and outlets. Outlets within
  six feet of a sink or other source of plumbing
  must be protected in order to minimize shock
  hazards. An unprotected outlet is illustrated in
  this picture

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• Safety showers must not be located directly
  over switches, outlets, equipment, or other
  sources of electrical energy such as those shown
  in the picture to the left.

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Power supplies represent a potentially lethal
source of electrical energy. Exposed connectors
such as banana clips (alligator clips) should
never be attached to a power supply or any other
high voltage, high current producing device.
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• Electrophoresis equipment containing high voltage
  power supplies are found in many laboratories.
• Care must be taken to use only approved
  equipment.
• Leads should be checked periodically for frays.

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• Flammable storage refrigerators are specially
  designed for flammable liquid storage. The
  interior of these types of refrigerators do not
  contain any potential spark sources such as
  lights and switches.

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Basic Electrical Safety Guidelines

• Learn the location of your electrical panels and
  shut-off switches so you can quickly disconnect
  power in the event of an emergency. Always leave
  at least a 3-foot clearance around electrical
  panels for ready access.
• Plan ahead for what steps will be taken in the
  event of a power loss.
• Conduct a periodic inspection of laboratory
  electrical equipment to be sure it is in good
  condition.
• Electrical outlets should have a grounding
  connection and accept three-prong plugs. Multiple
  plug outlet adapters are not allowed.

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Electrical Fires

• Unplug equipment first.
• Use dry chemical fire extinguisher.
• If fire is large, unplug equipment and call fire
  dept.
• Never use water!!
• .

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• Type A fire extinguishers use water to put out
  fires. They are not approved for use on
  electrical fires. Type A extinguishers are
  denoted by a pressure gauge at the top of the
  unit that indicates whether or not the
  extinguisher is fully charged