TM 5-3810-306-10 Proximity  sensing  devices  are  available  in  different types.    Some  use  boom  nose  (localized)  sensors  and others use full boom length sensors.  No warning may be given for components, cables, loads, etc. located outside of   the   sensing   area.   Responsibility   is   on   you,   the operator,  in  selecting  and  properly  setting  sensitivity  of these devices. Never rely soley on a device to protect you and your fellow workers from danger! Some variables which you must be aware of are: 1. Proximity    devices    detect    the     existence     of electricity -- not it’s quantity or magnitude. 2. Some proximity devices will detect only alternating   current   (AC)   --   not   direct   current (DC). 3. Some    devices    detect    radio    frequency    (RF) energy -- others do not. 4. Most  proximity  devices  simply  provide  a  signal (audible, visual or both) -- the signal must not be ignored. 5. Proximity   devices   often   become   confused   by complex or differing arrays of power lines/sources. Plan  ahead  and  plainly  mark  a  safe  route  before traveling  under  power  lines.  Erect  rider  poles  on  each side  of  the  crossing  to  assure  sufficient  clearance   is maintained. Overhead lines tend to blow with wind. Allow for this when determining safe operating distances. DO NOT store material under power lines or close to electrical power sources. Grounding the crane offers little or no protection from electrical hazards.  The grounding effect is limited by the wire  size  used,  the  condition  of  the  ground,  amount  of voltage and current present, etc. Power source contacts have   been   known   to   cause   serious   arcing   due   to grounding. Tag lines should always be made of non-conductive materials. Any   tag   line   that   is   wet   or   dirty   can   conduct electricity. Working in the vicinity of radio frequency transmission   towers/sources   may   cause   a   crane   to become electrically "charged." Survey the work site and develop    specific    safety    precautions    and    operating procedures, prior to commencing operations. If  contact  is  made  with  a  power  source  -  THINK  - DON’T PANIC. 1. Warn everyone to stay away from the crane. 2. Attempt to free the crane by operating the crane functions. 3. Stay  in  the  crane  until  the  power  source  has been turned off. You should, only as a last resort, attempt to leave the crane after contacting a power source. If it is absolutely necessary to leave the cab, JUMP COMPLETELY   CLEAR   OF   THE   CRANE   -   DO   NOT STEP OFF. Hop away with both feet together. DO NOT walk or run. Following  any  contact  with  an  energized  electrical source, thoroughly inspect the wire rope and all points of contact with the crane. 2-39