safety for domestic appliances

What is this guidance about?
This information sheet contains specific advice about
some of the ways of avoiding injury during the servicing
and repair of domestic appliances such as washing
machines, dryers, refrigerators/freezers, cooking
equipment etc, normally operating from a 230 volt
supply. Audio, TV and computer equipment are dealt
with in Safety in electrical testing: Servicing and repair
of audio, TV and computer equipment.1 Further advice is
given Safety in electrical testing at work: General
guidance 2 and other guidance on electrical safety (listed
under ‘Where can I get more information?’ on page 3).
How can injuries happen during testing?
The most significant danger to people carrying out
electrical testing work is that they might suffer an electric
shock. Any simultaneous contact of a part of the body
with a conductor that is live at a dangerous voltage, eg
one that is connected to the mains supply while another
part of the body is connected to an earth, will result in an
electric shock. There is also a risk of burn injuries
resulting from arcing when conductors are accidentally
short-circuited.
An electric shock can lead to serious injury, sometimes
fatal. Injuries can also occur when a person reacts to an
electric shock, for example by falling or touching another
hazard. Factors which are likely to increase the risk of
receiving an electric shock include the following:
(a) The majority of domestic appliances have large
areas of earthed metal that may be easily touched.
Touching exposed live conductors connected to the
mains supply at the same time as touching the
earthed metalwork will result in an electric shock;
(b) Some appliances could also be using water in their
operation, such as washing machines or
dishwashers. This may lead to an increased risk of
shock because water can conduct electricity and
reduces the resistance of the skin;
(c) When working on microwave ovens there may be a
risk of severe electric shock from the internally
generated high voltage (approximately 4kV);
(d) Work may be carried out in the customer’s home,
so people other than those doing the work
(including children) may also be at risk;
(e) Additional risks may be present at the customer’s
premises if their electrical installation is not
electrically sound, eg earthing, insulation
resistance, polarity.
Carrying out a risk assessment
To help you identify the precautions that are necessary
for carrying out electrical testing work safely, you need to
do an assessment of the risk of injury posed by the work
being done. When assessing the risk, you need to think
about the hazards that are present, who may be harmed
and how, and the effectiveness of existing precautions.
Bear in mind the examples of factors given in this
guidance which might increase the risk.
When carrying out a risk assessment for electrical
testing, ask yourself the following questions:
(a) Can the work be done with the appliance dead?
(Repairs and replacements of faulty parts can and
should be done with the appliance isolated from
the supply. Remove the plug or fuse supplying the
appliance. If the fuse is removed, steps should be
taken to prevent another person inadvertently
replacing it.)
(b) Is it absolutely necessary for someone to be
working on or near an appliance that is live at
dangerous voltages or current levels?
(c) Have suitable precautions been taken to avoid
danger and, where necessary, prevent injury?
(d) Is the person doing the work competent for that
type of work, or, if not, adequately supervised?
What precautions should I take?
Where possible, the work should be done with the
equipment dead (this is a requirement of the Electricity
at Work Regulations 19893). Otherwise, adequate
precautions, which should be identified in your risk
assessment, must be taken to ensure safety.
The following precautions are recommended as part of a
safe system of working for electrical testing of this
equipment.
Test areas
In all circumstances, it is necessary to create a safe
working environment for testing. A test area in which the
work is to be done should be defined. This should be
relatively straightforward in a workshop situation, but
may be more difficult when working in a customer’s
home.
Safety in electrical testing: Servicing
and repair of domestic appliances
HSE information sheet
Engineering Information Sheet No 35
In the customer’s home
When working in a customer’s home, the person
carrying out the testing should carry out a site risk
assessment to determine the steps necessary to create
a safe working environment.
(a) If you do not think it is safe to work in the home,
don’t. Remove the equipment to the workshop
where you can work safely;
(b) Consider erecting a temporary barrier to prevent
unauthorised people approaching the danger area;
(c) Allow plenty of space to work in. If you do get a
shock you may be less able to break contact
quickly, if at all, or are more likely to hit something
if you are working in a cramped area. Remove (or
move away from) any objects that may pose a
hazard. For example, if an appliance is situated in
a corner, consider pulling it out and working behind
it;
(d) Make sure everyone in the home is aware of the
dangers arising from the testing work, and that they
follow any precautions that are necessary. Ask for
children and pets to be kept from the area;
(e) Never leave an appliance unattended when it is in
a dangerous condition (eg with live conductors
exposed).
In the workshop
When testing is being done in a workshop, the following
precautions should be considered:
(a) Access to the test area should be limited as far as
is practicable to the competent persons carrying
out the testing. Suitable barriers may be provided
to help prevent unauthorised entry. Competent
persons must have adequate knowledge of the
electrical dangers associated with the appliances
and the precautions necessary to reduce the risk of
electric shock. Training must be provided as
necessary;
(b) Other people who may enter the test area from
time to time should be instructed about the hazards
that may be present and in particular be told not to
touch anything on the work bench. Their access
should be limited to what is strictly necessary;
(c) Adjacent test positions should be separated using
barriers to prevent a tester from reaching into
another test area;
(d) Soak test areas should, where possible, be
separate from the test benches and when
equipment is on soak test, its covers should be in
place.
Access to live parts
Where diagnostic testing needs to be carried out on live
appliances, the risk is most effectively controlled by
preventing access to the live parts. This can be achieved
in a number of ways:
(a) Prevent accidental contact with dangerous
conductors by the use of temporary insulation. This
could be commercially available transparent and
perforated material to allow moving parts to be
observed and for access to test probes.
Additionally, individual sleeves can be placed over
conductors. This may be difficult where the
conductor areas are small (connection size). In
these cases, ensure that a safe system of work,
incorporating the other relevant precautions listed
below, is being followed;
(b) The power supply should include a Residual
Current Device (RCD), with a rated tripping current
of, at most, 30mA. This may not be available on all
customers’ circuits, so a portable RCD should be
available;
(c) When printed circuit boards are being tested and
are taken out of the normal working position,
secure them in purpose-built jigs to provide
adequate support and to prevent them from falling;
(d) When working on microwave ovens, ensure that
the high-voltage internal source is not energised
while the oven cover is removed. Functional testing
to show whether or not the magnetron is operating
should be done with covers fitted.
Test equipment
Where possible, test equipment should be of a
proprietary design. In this case the manufacturer should
have taken account of its safety performance during use.
Where applicable, test equipment should be
manufactured to BS EN 61010,4 BS EN 615575 or
BS EN 61243-3.6
Purpose-built test equipment must be designed and
constructed to the same standards of safety as
proprietary equipment. Where equipment is mains
powered, it must be safe to use as a piece of electrical
equipment in its own right. In addition, the arrangements
for connecting it to the equipment under test must be
safe.
See also advice given in Safety in electrical testing at
work: General guidance 2 concerning the use of test
equipment.
Power supply earthing
When working on Class I (earthed enclosure) equipment
it is important that the earthing of the power supply to
the equipment is adequate and efficient. In customers’
premises this is likely to be unknown so it is important to
carry out a test to demonstrate the efficacy of the
earthing. The safe way to do this is to measure the earth
loop impedance of the power supply using an instrument
designed for that purpose. Make sure that you know
how to use the testing device and how to interpret the
results obtained. If the test indicates an inadequate
earth, the customer must be informed that the work
cannot continue until it has been rectified.
Remember that simple 'Go/No go' plug-in testers will in
general only provide a polarity check and an indication
that an earth may be present, but not its effectiveness.
What are the legal requirements?
The Electricity at Work Regulations 19893 are the
principal legislation relating to electrical testing activities
and regulation 14 is particularly relevant to live testing
activities. In addition, employers are required under
regulation 3 of the Management of Health and Safety at
Work Regulations 19997 to assess the risks to the health
and safety of their employees while they are at work, in
order to identify and implement the necessary
precautions to ensure safety.
References
1 Safety in electrical testing: Servicing and repair of
audio, TV and computer equipment Engineering
Information Sheet EIS35 HSE Books 2002
2 Safety in electrical testing at work: General
guidance Leaflet INDG354 HSE Books 2002 (single
copy free or priced packs of 5 ISBN 0 7176 2296 7)
3 Memorandum of guidance on the Electricity at
Work Regulations 1989. Guidance on Regulations
HSR25 HSE Books 1989 ISBN 0 7176 1602 9
4 BS EN 61010: 1993 Safety requirements for
electrical equipment for measurement, control and
laboratory use (full document is in 11 parts)
5 BS EN 61557: 1997 Electrical safety in low voltage
distribution systems up to 1000 V ac and 1500 V dc.
Equipment for testing, measuring or monitoring
protective measures
6 BS EN 61243-3: 1997 Live working. Voltage
detectors. Two-pole low voltage type
7 Management of health and safety at work.
Management of Health and Safety at Work Regulations
1999. Approved Code of Practice and guidance L21
(Second edition) HSE Books 2000 ISBN 0 7176 2488 9
Where can I get more information?
Electrical test equipment for use by electricians GS38
HSE Books 1995 ISBN 0 7176 0845 X
Electricity at work: Safe working practices HSG85
HSE Books 1993 ISBN 0 7176 0442 X
BS EN 50191: 2001 Erection and operation of electrical
test equipment
DASA Quality criteria (Section 2 ‘Competence’ and 3.1
‘Electrical safety tests’) Domestic Appliance Service
Association (DASA), 69 The Maltings, Stanstead
Abbotts, Herts SG12 8HG Tel: 01920 870173 (available
free on request)
While every effort has been made to ensure the
accuracy of the references listed in this publication, their
future availability cannot be guaranteed.
Further information
HSE priced and free publications are available by mail
order from HSE Books, PO Box 1999, Sudbury, Suffolk
CO10 2WA Tel: 01787 881165 Fax: 01787 313995
Website: www.hsebooks.co.uk (HSE priced publications
are also available from bookshops.)
For information about health and safety ring HSE's
InfoLine Tel: 08701 545500 Fax: 02920 859260 e-mail:
hseinformationservices@natbrit.com or write to HSE
Information Services, Caerphilly Business Park,
Caerphilly CF83 3GG. You can also visit HSE’s website:
www.hse.gov.uk
British Standards are available from BSI Customer
Services, 389 Chiswick High Road, London W4 4AL
Tel: 020 8996 9001 Fax: 020 8996 7001
Website: www.bsi-global.com
This publication may be freely reproduced, except for
advertising, endorsement or commercial purposes. The
information is current at 03/02. Please acknowledge the
source as HSE.
This leaflet contains notes on good practice which are
not compulsory but which you may find helpful in
considering what you need to do.
Printed and published by the Health and Safety Executive 03/02 EIS35 C200