Chelmsford Amateur Radio Society Intermediate Course (9) Safety - PowerPoint PPT Presentation

Chelmsford Amateur Radio Society Intermediate Course(9) Safety

• 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.

• 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.

• 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.

• 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.

• 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.

4 Metres

1 Metre

• 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.

• 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 by high winds, tree branches, icing, birds etc

• 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)

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

• 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 on the course correctly

• 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?
• Recall P=VI or I=P/VFormula for correct fuse is Current = Power/230
• A 1A current passing through the body may well be fatal before the fuse blows.

• The shack should be protected by an RCD and a well knownOFF 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.

• 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 HPA and ICNIRP produce guidelines on safe exposure levels
• See HPA “Investigation levels” document which gives guidanceon limits, above which a more detailed investigation is required to ensure the levels are acceptable. See - http://www.hpa.org.uk/