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 1:4 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:- Live=Brown, Neutral=Blue Earth=Green / Yellow • Avoid whiskers, trapped wires, and ensure that Cord Grips are secure, but don’t 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. RCD’s , 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.