Syllabus Sections:-
Working mobile and portable
8F4 52
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
52 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 CO2" 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 time
due 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
After
initial 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 :-
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.
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8F4
52 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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