Technical information

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Work on electrical devices should be done only after the power has been shut off in such a manner that it
cannot be turned on accidentally. Internal current-carrying devices such as capacitors must be discharged.
All "home-made" electrical apparatus should be inspected and approved by someone competent in
electrical circuitry before being placed in service.
Observe the following rules when working with electrical equipment:
• Ungrounded wiring and two-wire extension cords are prohibited. Worn or frayed extension cords
or those with broken connections or exposed wiring must not be used. All electrical devices must
be grounded before they are turned on.
• Extension cords are for temporary use, and are not to be used n place of permanent wiring.
• Volt Limit: Untrained persons may not work on live equipment carrying potentials greater than
50V.
• Use only tools and equipment with non-conducting handles when working with electrical devices.
• If you feel an electrical "tingle" while working with a piece of laboratory equipment, disconnect it
and consult with your supervisor. In the U.S., three-terminal (115 V AC) electrical wiring should
conform to the following color code:
• White = neutral wire
• Black = live/hot wire
• Green = ground wire
(When working with existing wiring, do not trust that this color scheme has been used correctly.)
• Do not short circuit the leads to a battery. Without a fuse, the internal resistance of the battery will
cause it to heat and possibly explode. Dangerous arcs or flashes may also be produced.
• A ground-fault interrupter does not assure protection against electrocution.
• All current transmitting parts of any electrical devices should be enclosed.
• When checking an operating circuit, keep one hand either in a pocket or behind the back, to avoid
grounding yourself.
• Maintain a work space clear of extraneous material, such as books, papers, and clothes.
• Never change wiring with the circuit plugged into a power source.
• Never plug leads into a power source unless they are connected to an established circuit.
• Remove rings, watches, or other such jewelry before working on electrical circuits.
• 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.
• Keep the use of extension cords to a minimum and cords as short as possible. Tie off excess cord
out of pathways.
• Do not use or store highly flammable solvents near electrical equipment.
• Multi-strip outlets should not be used in place of permanently installed receptacles.
• Keep access to electrical panels and disconnect switches clear and unobstructed (three feet of floor
space).
• Make certain that all electrical equipment (lamps also) is properly grounded.
• Be alert and aware of the dangers inherent in high voltage equipment.
In the event of a small electrical fire:
• Turn off the power source and unplug the equipment.
• Do not turn on the circuit until the cause of the fire has been established and the fault corrected.
• Report the fire to the Safety Office.
CRYOGENIC SAFETY
Handle any liquefied gas carefully. At these extremely low temperatures, these gases can produce an effect
on the skin similar to a burn. Eyes should be protected with a face shield or safety glasses. Gloves should
be worn. Stand clear of the boiling and splashing liquid and its issuing gas.
Should any liquefied gas
contact the skin or eyes, immediately flood that area of the body with large quantities of unheated water
and then apply cold compresses.