Seaward A252 User manual

A252 Portable Appliance Tester INDEX
It is strongly recommended that all sections of this manual are read and fully understood by all those
intending to carry out or supervise any activity involved in electrical safety testing using this test equipment.
INTRODUCTION..............................................................................................................................................2
Reasons for inspection and testing
Methods of construction for electrical safety
Test requirements to determine electrical safety
Safety test records
INSTRUMENT DESCRIPTION............................................................................................................................9
Controls and Indicators
APPLIANCE TEST PROCEDURES....................................................................................................................17
Precautionary Measures
Visual Inspection
Electrical Safety Verification
INSTRUMENT INTEGRITY...............................................................................................................................29
Calibration
Operation Checks
APPENDIX...................................................................................................................................................33
Useful Reference Material
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A252 Portable Appliance Tester INTRODUCTION
REASONS FOR INSPECTION AND TESTING
In order to satisfy the objectives of the Electricity at Work Regulations 1989, there is a clear need for a
structured programme of continual risk assessment for each and every item of electrical equipment in the
workplace. Such a programme should be monitored through reviews of the results obtained during regular
visual inspection and periodic electrical safety testing.
The frequency of inspection and testing will depend on the type of item and the manner in which it is used -
•static electrical items, such as desk-top computers, fax machines, photo-copiers etc. which are normally
used in offices, and other low-risk sector premises, may not need to be checked and tested as
frequently as hand-held industrial power tools and the like, which, even in normal use, can be subjected
to pretty arduous operating conditions and suffer considerable mechanical stresses.
•likewise, the environment in which an electrical item is used, or stored, should be also be taken into
account - a cold, damp, workshop contributing to a higher risk than a nice dry office, for instance.
Repaired items should be subjected to thorough inspection and testing, to ensure full compliance with
original manufacturers specifications and any relevant safety standards, before being returned to service.
In order to fully assess potential risks there is also a need for a clear understanding of how construction
methods and test requirements aim to provide 'electrical' safety.
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A252 Portable Appliance Tester INTRODUCTION
METHODS OF CONSTRUCTION FOR ELECTRICAL SAFETY
To provide the user with protection against electric shock general methods of construction must ensure
firstly that all 'live' parts are insulated and secondly that should this basic insulation fail the 'live' parts are
prevented from creating a hazard to the user.
This second level of protection is achieved either by 'earthing' all accessible conductive surfaces or by
providing 'double insulation' in the form of a second insulating layer or by reinforcing the primary insulation
layer.
Earthed equipment is referred to as Class I and earthing is achieved by connecting all accessible
conductive surfaces (the tool body or outer casing and associated fixings etc.) to the supply earth via a low
impedance protective conductor, then if any 'live' part comes into contact with these surfaces the hazardous
current is drawn harmlessly to earth through the protective conductor rather than through the person
holding the tool. The protective conductor is the green/yellow 'earth' wire in standard 3 core mains supply
leads.
Double insulated equipment is referred to as Class II. All accessible conductive surfaces are additionally
insulated from internal 'live' parts and components. No 'earth' wire is present in the supply lead. All Class II
equipment is identified by a prominent square within a square symbol.
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A252 Portable Appliance Tester INTRODUCTION
TEST REQUIREMENTS TO DETERMINE ELECTRICAL SAFETY
The most appropriate way of verifying electrical safety is to carry out a series of routine safety tests that
both reflect those tests used in the manufacturing process and, particularly in the hire industry, that take
into account the effects of normal wear and tear.
VISUAL INSPECTION
It is important when carrying out routine testing to first check for signs of undue wear and tear by a
thorough visual inspection - a nick in the supply cable or a cracked casing etc can easily lead to hazardous
situations when the power tool or appliance is in use.
ELECTRICAL SAFETY
The tests to verify satisfactory 'earth bonding' and insulation levels will depend on the basic construction of
the tool or appliance - Class I (Earthed) or Class II (Double insulated) - and the original standard to which it
was manufactured, the most common British Standards being BS2769 for hand held power tools, BS3456
for general appliances and BS415 for mains operated electronic, mainly audio/visual equipment.
However, clear guidance should be sought from the manufacturer, or importer, to determine the appropriate
requirement.
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A252 Portable Appliance Tester INTRODUCTION
EARTH BOND CONTINUITY
Most type testing standards, including those referred to above, require that the earth bond resistance,
between all accessible conductive surfaces and the 'earthing' terminal within the appliance, does not
exceed 0.1 Ohm and that compliance should be checked by resistance measurement using a test current
equal to 1.5 times the rated current or to 25 Amps, whichever is greater, from an a.c. voltage source not
exceeding 12 Volts.
The test current for BS415 equipment is limited to 8 Amps due to the wide use of printed circuit tracks in the
earth bond path.
In practice, routine testing will also include the protective conductor (Earth wire) in the supply lead and the
measurement will be made between the earth pin of the supply plug and exposed metal (conductive)
surfaces on the tool or appliance.
WARNING
High current Earth Bond tests may cause damage if inappropriately applied to certain equipment. The A252
does incorporate a special low current (100mA) Functional Earth test for sensitive equipment. If in doubt,
consult the manufacturer of the item before applying any test.
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A252 Portable Appliance Tester INTRODUCTION
ELECTRICAL INSULATION
To check the insulation, between the 'live' conductors (line and neutral) and all exposed metal surfaces, a
high voltage a.c. Flash Test is applied. The voltage applied will be dependant on the construction class of
the tool or appliance -
•500V the minimum test voltage recommended by the HSE in Guidance Note PM32
•1250V for standard Class I (earthed) tools and appliances
•3000V for routine testing of Class II (double insulated) equipment (2500V for BS415 equipment)
•3750V for Class II equipment following repair or reconditioning operations.
Under normal conditions the permissible leakage current at the appropriate flash test voltage should not
exceed 5mA. However, some Class I equipment may have higher inherent leakage due to an extra long
supply lead or high capacitance suppression filtering, or a combination of the two, under these conditions
an increased acceptance level, of up to 10mA, may be permissible. For certain sensitive equipment it may
even be advisable to not apply a Flash Test but to only carry out a 500V d.c. Megohmmeter test. If in doubt
advice must be sought from the appliance manufacturer.
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A252 Portable Appliance Tester INTRODUCTION
NOTES
All safety tests must be carried out with the supply switch of the tool or appliance in the ON position to
ensure that all 'live' parts are included when checking insulation.
Some specialised equipment with heavy duty motors etc. may employ contactor or relay start switching
techniques, therefore to apply a satisfactory insulation (flash) test through such devices the contacts must
be held closed by some, safe, manual means - the advice of the manufacturer must be sought on methods
to achieve this in the least hazardous manner.
Some 'trigger' operated equipment may require the switch to be temporarily held in the ON position with
insulating tape or string - under no circumstances should it be held in by hand,
REMEMBER TO RELEASE THE SUPPLY SWITCH WHEN TESTING IS COMPLETE.
Multi - function tools and appliances must be fully tested with supply and function switches set for each
operating mode.
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A252 Portable Appliance Tester INTRODUCTION
SAFETY TEST RECORDS
The recording of test results, to provide a traceable history of equipment worthiness, can also prove
beneficial as a management tool for monitoring the effectiveness of the overall maintenance system, for
reviewing test frequencies, and for asset tracking purposes etc.
To provide a meaningful structure for such results recording, CLARE have developed a fully featured,
paper-based, TEST LOG system with full recording facilities for equipment details, test routines, checklists,
and detailed test reports. With it's easy to follow format, it provides an invaluable reference to equipment
status and is therefore suitable for most industrial / workplace applications where routine testing to a regular
schedule is required.
For data intensive applications CLARE can also offer the DATAPAT 600 system which combines a bar-
code reader, electronic data logging and a comprehensive suite of management software. Fully inter-active
with all CLARE Portable Appliance Testers the system provides easy to follow, menu-driven, routines to
guide the user through data collection and storage, transfer of data - through an integral RS232 link - to a
host PC and manipulation of data to automatically up-date, or create, records and reports.
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A252 Portable Appliance Tester INSTRUMENT DESCRIPTION
A252
PORTABLE APPLIANCE TESTER
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A252 Portable Appliance Tester INSTRUMENT DESCRIPTION
The CLARE A252 instrument is specifically designed to provide a quick and simple means of verifying the
electrical safety of most commonly found Class I (Earthed) and Class II (Double Insulated) power tools and
appliances.
With additional facilities for testing even the most sensitive of Information Technology (IT) type equipment,
the A252 is ideally suited to both industrial and office / shop environments.
The instrument is fitted with Test Sockets for both standard 240V/13Amp (BS1363A) and industrial
110V/16Amp (BS4343) connectors.
Appliances fitted with other plug styles can be readily accommodated using suitable adaptors, refer to P.15
for more details.
Accessories supplied with the instrument, including a high voltage Safety Probe, Earth Return lead and a
simple to use Appliance Fault Simulator - for checking the integrity of the fault detection circuitry - are
stored in the compartment at the rear of the instrument.
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A252 Portable Appliance Tester INSTRUMENT DESCRIPTION
CONTROLS AND INDICATORS
The following section acts as a guide to the instrument and to provide familiarisation with each of the
controls and associated functions.
Supply Input the permanently attached mains lead is fitted with a 13A (BS1363A) plug for connection to a
240V a.c. Earthed supply. The plug top fuse should be rated at 3Amps. The lead is stored in the rear
compartment.
Supply Lamps these two lamps, 1 amber and 1 red, are used to indicate the condition of the Incoming
supply. It is important that the external supply circuit is correctly wired and provides a sound earth
connection for this instrument.
The amber lamp must be ON whenever the instrument is connected to a live mains supply. If the amber
lamp fails to glow AND / OR the red FAULT lamp is ON there is likely to be a connection fault on the supply
socket - such as reversed polarity of Line and Neutral or no Earth connection at the supply socket.
Disconnect the instrument immediately and have the supply fault investigated and corrected, by qualified
personnel, before re-using the suspect socket for either this instrument or any other tool or appliance.
NOTE
If neither lamp glows, check that the supply is ON - if it is ON check the wiring of the A252 plugtop and fuse.
Failing this, the fault is within the instrument. It must be withdrawn and thoroughly investigated and
corrected, by qualified personnel, before carrying out any appliance testing.
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A252 Portable Appliance Tester INSTRUMENT DESCRIPTION
Flash Test PASS/FAIL lamps glow to indicate the result of the applied test.
When applying a double insulated test via the flash probe a PASS indication should be taken to indicate
that no fault was found at the point of application of the probe.
Test Selector rotate switch and set to required test as follows
for Class I equipment
Earth Test also use appropriate Earth Return socket to select 25A or 8A test current.
500v Flash mainly only used for equipment with inherently high capacitance suppression.
1250v Flash for normal Class I equipment.
for Class II equipment
2500v Flash for routine testing of audio/visual appliances and other BS415 related equipment.
3000v Flash for routine testing.
3750v Flash for repaired or reconditioned tools.
for Information Technology (IT) Equipment
Functional Earth 100mA continuity test, purely functional - not to be confused with safety Earth Test.
500vDC Megohms for measuring insulation resistance if Flash Test considered too severe.
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A252 Portable Appliance Tester INSTRUMENT DESCRIPTION
Set Inf. These two controls, adjacent to the test selector, are multi-turn adjusters for setting-up the
associated metering circuits. Select Earth Test or Functional Earth, plug the clip lead into the appropriate
socket, this also selects the associated metering range, and isolate the clip. Depress the main Test button
and adjust the Set Inf. control until the meter pointer is on the Inf. mark of the appropriate scale.
Earth Return Sockets These sockets are used, with the earth return clip lead (see below), to select the
test current to be applied Use the yellow socket for the 8A test required for electronic audio/visual (BS415)
apparatus or the green socket for the 25A test required for power tools and electrical appliances. The blue
100mA socket is used when applying the low current Functional Earth test on sensitive IT equipment.
Earth Return Clip Lead this lead is used to complete the Earth circuit test path, it is plugged into the
appropriate green, yellow or blue Earth Return socket and then clipped to clean, exposed, metalwork on the
appliance. Ensure that the clip is soundly connected to prevent any high current arcing causing damage to
polished surfaces. This lead is not required when testing double insulated appliances.
DEPRESS TO TEST this momentary action push button is used to apply the selected safety test.
10mA TRIP this push button is used to select the higher trip threshold for Class I Flash Tests.
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A252 Portable Appliance Tester INSTRUMENT DESCRIPTION
Flash Test Probe this high voltage safety probe is used when applying the Flash Test, or taking Insulation
Resistance measurements, with Double Insulated appliances.
The test tip, which is exposed by depressing the red actuator on the probe handle, should be applied to any
exposed metal on the appliance including screwheads and rivets etc and to casing joints, particularly
around handgrips, switches and cable entries.
The high voltage is only applied when the TEST button is depressed. Tiny sparks and a light crackling
sound may be observed when applying the test tip, this is quite normal at such high voltage levels and
should not be confused with a flash-over, which, if it occurs, will be clearly indicated by the Flash Fault lamp
and alarm.
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A252 Portable Appliance Tester INSTRUMENT DESCRIPTION
Test Sockets the two sockets fitted as standard, 240V/13A (BS 1363A) and industrial 110V/16A (BS 4343),
will suit most appliances found in the workplace environment.
Equipment fitted with other plug styles can be readily accommodated by making and using suitable
adaptors generally as illustrated below.
Inter-connection and link wires must be kept as short as is practical and must be suitably rated to withstand
the high current and high voltages that will be present during a Safety Test.
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A252 Portable Appliance Tester TEST PROCEDURES
APPLIANCE
TEST PROCEDURES
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A252 Portable Appliance Tester TEST PROCEDURES
PRECAUTIONARY MEASURES
Appliance testing, by it’s very nature, can be hazardous and various common sense precautions should be
observed -
•Ensure that the person responsible for testing is competent and fully trained in the general principles of
Safety Testing AND the correct use of any required test instruments.
•Ensure, where possible, that a ‘test area’ is clearly defined and offers limited access to all persons not
involved in the testing.
•Ensure that the appliance to be tested is on an insulated (non-conducting) worksurface - never use
metal, or metal edged, worktops - a robust wooden bench with a securely fitted rubber covering is
best.
For those ‘on site’ situations where dedicated test areas are unavailable, an old plastic tea tray or rubber
car mat can come in very useful for creating the insulated worksurface. Do not use ‘anti-static’ matting
as this is highly conductive - which rather defeats the object.
•Arrange appliances and test equipment so that controls are easily accessible without having to reach
over or lean across the item during testing - never come into contact with an appliance under test.
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A252 Portable Appliance Tester TEST PROCEDURES
•Securely fix down motorised appliances and ensure that moving parts are adequately guarded.
•Check that the intended test is suitable for the appliance - if in doubt contact the Manufacturer or
Importer of the appliance.
Although CLARE are the recognised experts in the field of Electrical Safety Testing we can’t possibly have
an intimate knowledge of every item of electrical apparatus in the marketplace!
•Always carry out a thorough Visual Inspection, and complete any necessary repairs, before applying any
electrical test.
•If any Safety Test failure occurs ensure that the appliance is fully re-tested after undergoing appropriate
repairs.
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A252 Portable Appliance Tester TEST PROCEDURES
VISUAL INSPECTION
Before applying the Earth Bonding and Insulation tests a thorough visual inspection of the appliance must
be carried out. This may well form the greater part - 75% or more - of any test routine.
CASING
Check for signs of undue wear, cracks or dents, missing components such as guards, covers or hand grips
etc.
Ensure that all screws and catches are present and secure.
Check for evidence of excessive dust and dirt build up in and around any ventilation slots, especially
carbon-brush dust which is highly conductive and could create a 'live' path around insulation barriers.
Also ensure that all movable guards operate smoothly.
SUPPLY Lead
Check for any signs of damage or fraying along the entire length, this should also include any extension
lead that may be regularly used with the appliance.
Ensure that any cable entry or connector is sound and secure.
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