chelmsford amateur radio society intermediate course (9) safety

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Chelmsford Amateur Radio SocietyIntermediate Licence Course

Christopher Chapman G0IPU Slide Set 2(9) Safety

Chelmsford Amateur Radio Chelmsford Amateur Radio Society Society

Intermediate CourseIntermediate Course(9) Safety(9) Safety

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Remember the Foundation Slides

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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.

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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.

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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.

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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.

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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.

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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.

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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

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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)

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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

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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 correctlyYou will have to wire a plug here correctly

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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.

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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.

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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.

chelmsford amateur radio society intermediate course (9) safety

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