Chelmsford Amateur Radio Society Intermediate Course (9) Safety

1
Chelmsford Amateur Radio Society Intermediate
Course(9) Safety
2
Remember the Foundation Slides
3
Soldering - Safety Issues(Part 1)

• The soldering iron stand is a safe place to keep
  the iron when hot.
• This minimises risk of skin contact and burns.
• It often also prevents the iron overheating when
  not in use.

4
Soldering - Safety Issues(Part 2)

• The fumes from soldering, usually the heated
  flux, can cause respiratory problems, especially
  for asthmatics.
• The work bench must be kept well ventilated to
  minimise the inhalation of the fumes.

5
Soldering - Safety Issues(Part 3)

• Goggles or suitable glasses should be worn when
  soldering to prevent solder splashed and spitting
  flux causing eye damage.
• Note This will also be mandatory on this course.
  

6
Workshop Safety - General(Part 1)

• Use tools carefully.
• Clear tidy work place.
• Work away from the hands or body in case of
  slips.
• Items being worked on, must be securely held to
  prevent it moving when being drilled, sawn or
  filed.

7
Workshop Safety - Drilling(Part 2)

• A chuck key left in the chuck can cause serious
  injury to self or others in the room or nearby.
• Before drilling a hole use a centre punch.
• This has a safety implication as well as aiding
  neat workmanship.

• Any activity, especially drilling, can throw up
  swarf. This can cause cuts and eye damage.
• Suitable precautions such as Goggles or suitable
  glasses should be worn.

8
Ladders - Safety

• Take care when erecting ladders etc.
• The correct angle can be expressed as a 14 ratio
• Ladder should be suitably secured at the top or
  held at the bottom by an adult.
• Over-reaching can cause a fall or cause the
  ladder to slip, rotate.
• Use a tool belt to carry tools this will help
  prevent falling objects.
• Wear hard hats when working at height or when
  others are working at height.

9
Antenna Installation Safety

• Electric shock can result from Antennas and
  Ladders coming into contact with, or arcing from
  overhead power lines.
• Even wooden ladders are dangerous in this
  context.
• A wet wooden ladder will conduct electricity.
• Antennas and feeders must be kept well clear.
• Feeders / antennas must be soundly fixed in case
  of being accidentally being pulled, high winds,
  icing, bird strikes

10
Safety Earthing (Foundation)

• Ensure shack equipment is run from a common mains
  earth to prevent earth loops - use filtered mains
  boards and ferrite rings correctly.
• Modern Gas Water Pipes can give high resistance
  earth.
• Beware of House earths above earth potential
• Do not mix Mains Earth (for safety) with RF
  Earths (for Antennas)

11
Mains Cables

• Avoid trailing mains leads on the shack floor -
  Trip Hazards!
• Same as for Foundation.
• Damage to self.
• Damage to Equipment.
• Cost of Replacement / Repair

12
Mains Plugs Fitting

• Flex Colours- LiveBrown,
  NeutralBlue EarthGreen / Yellow
• Avoid whiskers, trapped wires, and ensure that
  Cord Grips are secure, but dont pierce the
  insulation.
• Fuses are to protect the equipment and you.
• ALWAYS FIT THE RIGHT FUSE FOR THE EQUIPMENT.
• You will have to wire a plug here correctly

13
Mains Plug Fuses

• The fuse must blow first.
• Not all faults are short circuits.
• So the fuse must blow before causing a fire.
• Either in the cable or the equipment.
• A 1 Amp panel mounted fuse may protect the
  equipment, but what fuse is in the plug to
  protect the cable?
• Formula for correct fuse is Current Power/230.
• A 1A current passing through the body may well be
  fatal before the fuse blows.

14
RCDs , OFF Switch, Lightning

• The shack should be protected by an RCD and a
  well known OFF switch, known to all in the house.
  
• These operate much faster than a fuse and are
  much more sensitive to fault conditions hence
  providing better protection against
  electrocution.
• Any external use of mains power MUST use an RCD.
• Lightning - Disconnect your Antennas !
• A nearby strike can also be dangerous to you /
  equipment.

15
RF Radiation Issues

• Strong fields from antenna and feeders cause
  energy to be absorbed by the body, cause heating
  as in a microwave oven.
• RF burns can be painless at the time and are only
  apparent after the event when the damage is done.
  
• The eyes are particularly susceptible since there
  is no cooling from the blood supply.
• Standing in front of high gain antennas or
  looking down waveguides are actions most likely
  to risk over exposure. Don't!
• Dont Panic
• The NRPB and ICNIRP produce guidelines on what
  constitutes safe exposure. See Investigation
  levels document which gives in reasonably
  straightforward terms guidance on limits, above
  which a more detailed investigation is required
  to ensure the level of radiation and absorption
  is acceptable.