Safety

Working mobile and portable

8F4   Understand that operating in temporary premises and/or outdoors can introduce new hazards (i.e. overhead power lines, inadequate electrical supplies, trailing cables, damp ground, excessive field strengths).

Portable operation could be considered as from any location where the set up of the station is not permanent, the whole station including antennas being set up on a clear site to an operational shack in a matter of hours.

A clear site is ideally what you would like to have to set up a station but there are always bound to be hazards one way or another.

If you are in a field running an open day and there are overhead power cables you must take this into account, you may be using a generator to provide Mains so consider a safer option of using batteries. As you learned in the foundation syllabus trailing cables are a no no so keep them tidy. If the ground is damp then the risk there of not only slipping over but also a risk if there is lightning. you need to access the field strength of radiation.

on page 14 under the heading "Taking safety with you."

8F4   continued: Recall the additional safety precautions that should be taken whilst operating in temporary premises and/or outdoors i.e.

• site survey / risk assessment
• cable routing/protection
• correct fusing
• use of Residual Current Devices (RCDs,RCBO's)
• no adjustments or repairs to live equipment.

What are RCD and RCBO ?

RCBO stands for 'Residual Current Breaker with Over-Current'. As the name suggests it protects against two types of fault and in essence combines the functionality of an MCB and RCD, whereas an RCD is designed solely to protect against earth leakage and an MCB protects only against over-current

Let us first look at the two fault conditions:

Residual Current, or Earth Leakage

This occurs when there is an accidental break in a circuit through poor electrical wiring or DIY accidents such as drilling through a cable or cutting through a cable with the lawn mower. In this instance the electricity must go somewhere and choosing the easiest route travels through the lawnmower or drill to the human causing electric shock.

Over-Current takes two forms:

Overload - Occurs when too many devices are in use on the circuit, drawing an amount of power which exceeds the capacity of the cable.

Short Circuit - Occurs when there is a direct connection between the live and neutral conductors. Without the resistance provided by the normal circuit integrity, electrical current rushes around the circuit in a loop and multiplies the amperage by many thousands of times in just milliseconds and is considerably more dangerous than Overload.

An RCBO protects against both types of fault.

The following are items that should be considered in no particular order and the list is not intended as a final check list before going portable, your own personal location may involve other problems and a proper "Risk Assessment should be made".

So consider the following:-

Prior to the setting up carry out a site survey / risk assessment to :-

• Assess the entrance to the site - no good arriving towing a trailer mast and not being able to turn a narrow right hand corner with the trailer


• Assess site for any overhead power line or other cables


• Assess the ground condition of the site for holes / manhole covers over drainage systems


• Assess the site for the liability to flooding - even if only locally


• Assess the site for supply of water


• Assess the site for security at night


• Assess the site for the ability of entrance of the emergency service particularly the Fire and Rescue Service they need at least a 4m wide gate and 4.5m high clear space and would the ground support the weight of the fire engine


• Where is the nearest fire hydrant


• Prepare a site map and annotated with
  
  
  • The 6 figure map reference and description of the location
  
  
  • To indicate location of caravan(s) / tent(s) / parking / generator / fuel store / gas store / location of BBQ / any obstacles that would prevent ready access for emergency services
  
  
• Prepare an evacuation plan and provide several notices ready to be placed in prominent places


• Where are the nearest toilets / wash facilities or have they to be provided by members, if so what would the arrangement be for visitors


• Where is the nearest "take away"!!


• Is there a local pub near by !!


• How many people and cars etc. can the site accommodate safely

Upon arrival at the site arrange

• Who is designated in overall control of the site


• Who would call the emergency services if needed


• Decide upon the time of a site briefing


• Display the evacuation plan in the event of an emergency and identify the Emergency Alarm Point and means of raising the alarm (A BIG BELL WORKS WELL !!)


• Ensure that a log on and off site of members & visitors is maintained up to date, so that in the event of an emergency a check can be made that all persons are safe


• The fire precaution points a minimum of two, indicated by good signs RED with white letters "FIRE POINT" with one each of "a foam" and "a CO_2" fire extinguishers plus if you like a sand bucket and bucket of water - be sure those on site know which to use on what type of fire. NO water or foam on an electrical fire!!


• The assembly point in the event of an emergency and have it property marked as such


• Designated easy access route to the centre of the site for emergency vehicles


• Designated car parking area for visitors and members - if a car(s) needs to be brought from this location then is must be parked least 6m from any tent or caravan or cooking appliance


• Designated camping area for tents and caravans minimum of 6m between each and 6m to any associated vehicle


• The location of the main and subsidiary operating positions location


• The location of the "inside" cooking facilities especially with regards to possible fire


• The location of the BBQ - keep it away from fuel store, generator and at least 6m from a caravan or tent !!!!


• The location for the erection of the main antennas and subsidiary antennas


• The location of the generator for temporary power


• The location of the fuel dump - note not more than 50 litres of fuel at any one place and allow 6m between locations - all fuel containers must be of the type approved for the fuel


• The cable run from generator to temporary shacks


• The use of RCDs


• The location of the main shut off switch and fused distribution box

What happens if there is an emergency

• Sound the Emergency Alarm

• Action your plan to deal with fire / injury / illness

• a small fire can develop into a big one so call the fire service

• ensure everyone is safe or try to find location of anyone trapped and their condition WITHOUT risking life

Hold Site Briefing to discuss :-

• the emergency plan

• the location of the fire points / assembly point

• who takes charge if the originally designated person has to leave site

• who would phone for the emergency services if the originally designated person is off site

• designate a person who would meet the emergency services at the public road entrance having also told any near by property occupiers of the problem and to expect the emergency services

• designate a person who would be responsible for dropping wire aerials that might hinder emergency access

• up date the site plan to be given to the emergency services upon their arrival showing hazards point - fuel - gas cylinders

• ensure that all present at the site briefing know the location of the fire points / assembly point / fuel dump AND indicate NO SMOKING in the area.

• ensure that all on site know that fuelling the generator is the most dangerous timedue to fumes and potential sparks so prior to refuelling the generator - SHUT OFF the generator - close down ALL operating position even those running low power from battery.

• ensure that all present know that the use of cooking and heating facilities must be used with extreme caution as the fire risk is very high

Afterinitial radio equipment checks consider :-

• field strengths especially if using linear amplifier at full legal limit

• is the generator able to cope with the current requirements of the site

• trip or low slung hazards of power cables

• trip or low slung hazards of antenna feeder cables

• termination of aerials near to the ground and their high voltage points

• what you are going to do with waste materials, such as crisp packets left over food etc and any related fire hazards to do with bags of rubbish

What happens if it rains and /or there are high winds regarding:-

• your club members - is there enough dry shelter cover for them?

• the generator - what protection has it to keep it functioning even though it is raining

• masts - are they able to withstand high winds or must they be taken down - if so how long would it take to lower the mast(s)

• damp ground - consider faulty mains cables from generator - lightning and closeness to trees

• is there any permanent shelter that could be used even temporarily whilst the storm passed - is there a local pub near by ???

What happens if there is radio equipment failure :-

• is there any reserve equipment

THEN

Have a very good field weekend and clear up any rubbish to leave the site as clean or cleaner than when you arrived.

The above photograph is typical of a BRATS' field weekend.

8F4   continued: Recall that mains supplies in other countries may be of a different voltage or frequency; utilise plugs and sockets and that UK specified equipment may not be suitable or hazardous if connected and used

Outside to UK, countries use mains power at voltages between 100 V and 127 V with plugs and sockets quite different from those in UK.. Because of the difference the use of equipment designed to operate on the UK standard will not necessarily be suitable to operate on other voltage nor frequencies and in any event the standard UK plug will not fit into a different designed outlet.

Even using a plug converter will NOT provide a safe link as the plug converter will generally not change the voltage of operation unless it has been designed with a transformer built in..

see more on page 15 first column.

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The origin of some of the text on this page is from the RSGB with additions by the web master

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