DC MUSEUM

SAFETY PRECAUTIONS
ELECTRICAL

GENERAL PRECAUTIONS

  1. All repairs and maintenance on electrical equipment shall be done by authorized or assigned persons only.
  2. All electrical leads shall be considered ALIVE until tested with meter or test lamp, positively known to be in good condition.
  3. Persons working around live circuits shall not approach closer than 1 foot, regardless of voltage, except to accomplish particular mission.
  4. The use of bare fingers for determining whether a circuit is energized can be fatal even with low voltages and is strictly forbidden.
  5. Covers for all fuse boxes, junction boxes, lever type boxes and wiring accessories shall be habitually closed.
  6. All cables in zones subject to mechanical injury shall be protected by metal casing.
  7. All portable cables shall be free of splices, the proper length, and of sufficient cross-sectional area for current requirements.
  8. No person shall take loose metal objects (in pockets or otherwise) above open electrical apparatus.
  9. Stowage or insertion of foreign articles in or near switchboards, control appliances, panels, etc., is strictly forbidden.
  10. The electrical charge retained by electrical machinery (especially amplifiers) when secured is in certain cases sufficient to cause severe shock. Discharge the equipment to ground before working on it. Prior to touching a condenser which is connected to a de-energized circuit, or which is disconnected entirely, short circuit the terminals.

SWITCHING

OPENING SWITCHES

  1. Use only one hand for switching. Keep free hand clear at all times.
  2. Secure and tag switch if work is to be done on circuit.

CLOSING SWITCHES

  1. Before closing a switch, make sure that:
    1. The circuit and appliance are ready.
    2. Men near moving machinery are notified to stand clear.
    3. Fuses are proper for protection.
    4. Circuit breakers and all other protective devices are set and operative.

CARE AND MAINTENANCE

CLEANING

  1. Cleaning at energized switchboards, panels, boxes, etc., shall be limited to removing loose dirt with painter’s duster having NO METALLIC PART and made of soft bristles about 4” long, or a bellows or vacuum cleaner having no metallic part on or near the nozzle.
  2. Alcohol shall not be used for cleaning.
  3. When working with paints, varnishes, or any inflammable vapors in confined spaces, ample ventilation must be provided to prevent accumulation of vapors.

SERVICING OF EQUIPMENT

DE-ENERGIZED CIRCUITS

  1. Open and secure the main supply or cutout switches in each circuit.
  2. Tag each circuit to be worked on. Do not rely on loose card signs. Separate tags shall be used by each repair party working on the circuit. Each party shall remove only its own tag.
  3. The following precautions should be taken:
    1. Provide ample lighting.
    2. Remove loose clothing.
    3. Insulate worker from ground, by use of rubber, Bakelite, dry wood, or several layers of dry canvas.
    4. Cover working metal tools with insulating rubber or vinyl tape (NOT FRICTION TAPE).
    5. Worker should insulate live metal parts near work before proceeding with repair.
    6. Use only one hand. Wear rubber gloves on both hands where work permits.
    7. Have men stationed by circuit breakers or switches, and telephones manned if necessary, to expedite securing of circuits in the event of casualty.
    8. A man qualified in first aid for electric shock shall stand by during the entire period of repair.

ELECTRICAL FIRES

In case of electrical fire:

  1. De-energize circuit.
  2. Report condition to the OOD by messenger or telephone.
  3. Secure ventilation in the vicinity.
  4. Extinguish fire by use of CO2 FIRE EXTINGUISHER DIRECTED AT THE BASE OF FLAME.
  5. Before using other extinguishing mediums consider location, amount of space, gases formed, etc.