IEC 60335-2-91:2008

IEC 60335-2-91
Edition 3.0 2008-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Household and similar electrical appliances – Safety –
Part 2-91: Particular requirements for walk-behind and hand-held lawn trimmers
and lawn edge trimmers
Appareils électrodomestiques et analogues – Sécurité –
Partie 2-91: Règles particulières pour les coupe-gazon et les coupe-bordures
portatifs et à conducteur à pied

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IEC 60335-2-91
Edition 3.0 2008-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Household and similar electrical appliances – Safety –
Part 2-91: Particular requirements for walk-behind and hand-held lawn trimmers
and lawn edge trimmers
Appareils électrodomestiques et analogues – Sécurité –
Partie 2-91: Règles particulières pour les coupe-gazon et les coupe-bordures
portatifs et à conducteur à pied

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
X
CODE PRIX
ICS 65.060.70 ISBN 2-8318-9999-0
– 2 – 60335-2-91 © IEC:2008
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Definitions .8
4 General requirement.9
5 General conditions for the tests .9
6 Classification.9
7 Marking and instructions.10
8 Protection against access to live parts.11
9 Starting of motor-operated appliances .11
10 Power input and current .11
11 Heating .11
12 Void.11
13 Leakage current and electric strength at operating temperature.11
14 Transient overvoltages .11
15 Moisture resistance .11
16 Leakage current and electric strength.12
17 Overload protection of transformers and associated circuits .12
18 Endurance.12
19 Abnormal operation .12
20 Stability and mechanical hazards .12
21 Mechanical strength .14
22 Construction .15
23 Internal wiring.17
24 Components .17
25 Supply connection and external flexible cords .17
26 Terminals for external conductors.18
27 Provision for earthing .18
28 Screws and connections .18
29 Clearances, creepage distances and solid insulation .18
30 Resistance to heat and fire.18
31 Resistance to rusting.18
32 Radiation, toxicity and similar hazards.19
Annexes .24
Annex B (normative) Appliances powered by rechargeable batteries.24
Annex D (normative) Thermal motor protectors.26
Annex I (normative) Motors having basic insulation that is inadequate for the rated
voltage of the appliance.26
Annex AA (informative) Safety signs and symbols which may be used on lawn
trimmers and lawn edge trimmers .27
Annex BB (informative) Vibration .29

60335-2-91 © IEC:2008 – 3 –
Annex CC (informative) Noise test code – Engineering method (grade 2) .34
Annex DD (informative) Example of a material and construction fulfilling the
requirements for an artificial surface .40
Annex EE (informative) Safety instructions .42
Bibliography.44

Figure 101 – Guard, lawn trimmer (see 20.101.1) .20
Figure 102 – Guard, lawn edge trimmer (see 20.101.2).21
Figure 103 – Guard strength test (hand-held appliances) .22
Figure 104 – Cutting head strength test (see 21.102).22
Figure 105 – Cutting means measurement (see 22.103) .23
Figure BB.1 – Examples of transducer location/orientation (hand-held trimmers) .32
Figure BB.2 – Examples of transducer location/orientation (walk-behind machines).33
Figure CC.1 – Microphone positions on the hemisphere (see Table CC.1) .35
Figure DD.1 – Sketch of the measurement surface covered with an artificial surface
(not to scale) .41

Table CC.1 – Co-ordinates of microphone positions.36
Table CC.2 – Absorption coefficients .37

– 4 – 60335-2-91 © IEC:2008
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-91: Particular requirements for walk-behind
and hand-held lawn trimmers and lawn edge trimmers

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60335-2-91 has been prepared by IEC subcommittee 61F: Safety
of hand-held motor-operated electric tools, of IEC technical committee 61: Safety of
household and similar electrical appliances.
This third edition cancels and replaces the second edition published in 2002. It constitutes a
technical revision. Main changes in this edition include the revised endurance test in
Clause 18; Annex B, which allows for battery-powered trimmers; and addition of informative
Annexes BB, CC and EE on vibration, noise and safety instructions.
This bilingual version, published in 2008-09, corresponds to the English version.

60335-2-91 © IEC:2008 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
61F/710/FDIS 61F/713/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
This part 2 is to be used in conjunction with the latest edition of IEC 60335-1 and its
amendments. It was established on the basis of the fourth edition (2001) of that standard.
NOTE 1 When “Part 1” is mentioned in this standard, it refers to IEC 60335-1.
This part 2 supplements or modifies the corresponding clauses in IEC 60335-1, so as to
convert that publication into the IEC standard: Safety requirements for walk-behind and hand-
held lawn trimmers and lawn edge trimmers.
When a particular subclause of Part 1 is not mentioned in this part 2, that subclause applies
as far as is reasonable. When this standard states “addition”, “modification” or “replacement”,
the relevant text in Part 1 is to be adapted accordingly.
NOTE 2 The following numbering system is used:
– subclauses, tables and figures that are numbered starting from 101 are additional to those in Part 1;
– unless notes are in a new subclause or involve notes in Part 1, they are numbered starting from 101, including
those in a replaced clause or subclause;
– additional annexes are lettered AA, BB, etc.
NOTE 3 The following print types are used:
– requirements proper: in roman type;
– test specifications: in italic type;
– notes: in small roman type.
Words in bold in the text are defined in Clause 3. When a definition concerns an adjective, the adjective and the
associated noun are also in bold.
A list of all parts of the IEC 60335 series, under the general title: Household and similar
electrical appliances – Safety, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – 60335-2-91 © IEC:2008
INTRODUCTION
It has been assumed in the drafting of this international standard that the execution of its
provisions is entrusted to appropriately qualified and experienced persons.
This standard recognizes the internationally accepted level of protection against hazards such
as electrical, mechanical, thermal, fire and radiation of appliances when operated as in
normal use taking into account the manufacturer's instructions. It also covers abnormal
situations that can be expected in practice and takes into account the way in which
electromagnetic phenomena can affect the safe operation of appliances.
This standard takes into account the requirements of IEC 60364 as far as possible so that
there is compatibility with the wiring rules when the appliance is connected to the supply
mains. However, national wiring rules may differ.
If an appliance within the scope of this standard also incorporates functions that are covered
by another part 2 of IEC 60335, the relevant part 2 is applied to each function separately, as
far as is reasonable. If applicable, the influence of one function on the other is taken into
account.
This standard is a product family standard dealing with the safety of appliances and takes
precedence over horizontal and generic standards covering the same subject.
An appliance that complies with the text of this standard will not necessarily be considered to
comply with the safety principles of the standard if, when examined and tested, it is found to
have other features that impair the level of safety covered by these requirements.
An appliance employing materials or having forms of construction differing from those detailed
in the requirements of this standard may be examined and tested according to the intent of
the requirements and, if found to be substantially equivalent, may be considered to comply
with the standard.
60335-2-91 © IEC:2008 – 7 –
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-91: Particular requirements for walk-behind
and hand-held lawn trimmers and lawn edge trimmers

1 Scope
This clause of Part 1 is replaced by the following.
This International Standard deals with the safety of electric powered walk-behind and hand-
held lawn trimmers and lawn edge trimmers, with cutting element(s) of non-metallic
filament line or freely pivoting non-metallic cutter(s), with a kinetic energy of not more than
10 J each, used by a standing operator for cutting grass, their rated voltage being not more
than 250 V for a.c. or 50 V d.c.
In this standard, hand-held and walk-behind lawn trimmers and lawn edge trimmers are
referred to collectively as trimmer(s).
So far as is practicable, this standard deals with the common hazards presented by trimmers
which are encountered by all persons in the normal use and reasonably foreseeable misuse of
the trimmers.
NOTE 101 Attention is drawn to the fact that in many countries additional requirements are specified by the
national health authorities, the national authorities responsible for the protection of labour, the national water
supply authorities and similar authorities.
This standard does not apply to
– scissor type or lawn trimmers and lawn edge trimmers with cutting means other than
those described above;
– self-propelled lawn trimmers or lawn edge trimmers;
– lawn trimmers or lawn edge trimmers which do not have a distance of at least 600 mm
between the cutting means control and the cutting head;
– battery-powered trimmers fitted with batteries that have to be removed for charging.
NOTE 102 Requirements for tools with this type of battery can be found in Annexes K and L of IEC 60745-1.
EMC and environmental aspects, except noise, have not been considered in this standard.
NOTE 103 The method of calculating the kinetic energy for the purposes of this standard is given in 22.103.
2 Normative references
This clause of Part 1 is applicable except as follows.
Addition:
IEC 60068-2-75, Environmental testing – Part 2-75: Tests – Test Eh: Hammer tests
IEC 60320 (all parts), Appliance couplers for household and similar general purposes

– 8 – 60335-2-91 © IEC:2008
IEC 60320-2-3, Appliance couplers for household and similar general purposes –
Part 2-3: Appliance couplers with a degree of protection higher than IPX0
ISO 354:2003, Acoustics – Measurement of sound absorption in a reverberation room
ISO 3744:1994, Acoustics – Determination of sound power levels of noise sources using
sound pressure – Engineering method in an essentially free field over a reflecting plane
ISO 3767-1:1998, Tractors, machinery for agriculture and forestry, powered lawn and garden
equipment – Symbols for operator controls and other displays – Part 1: Common symbols
ISO 3767-3:1995, Tractors, machinery for agriculture and forestry, powered lawn and garden
equipment – Symbols for operator controls and other displays – Part 3: Symbols for powered
lawn and garden equipment
ISO 8662-1:1988, Hand-held portable power tools – Measurement of vibrations at the handle
– Part 1: General
ISO 11201:1995, Acoustics – Noise emitted by machinery and equipment – Measurement of
emission sound pressure levels at a work station and at other specified positions –
Engineering method in an essentially free field over a reflecting plane
ISO 12100-1:2003, Safety of machinery – Basic concepts, general principles for design – Part
1: Basic terminology, methodology
ISO 11688-1:1995, Acoustics – Recommended practice for the design of low-noise machinery
and equipment – Part 1: Planning
ISO 11684:1995, Tractors, machinery for agriculture and forestry, powered lawn and garden
equipment – Safety signs and hazard pictorials – General principles
3 Definitions
This clause of Part 1 is applicable except as follows.
3.1.9
Replacement:
normal operation
operation of the appliance at rated voltage with the load necessary to attain rated power input
NOTE The trimmer is operated at no-load. Automatic line extenders must be disabled.
3.5.2
Replacement:
hand-held appliance
appliance which is supported by hand, possibly assisted by wheel(s), skids or harness etc.
and constructed such that it cannot maintain its operating position without being held by an
operator
3.101
walk-behind appliance
appliance which is ground supported, controlled by an operator walking behind and
constructed such that it maintains its operating position without being held by an operator

60335-2-91 © IEC:2008 – 9 –
3.102
lawn trimmer
grass trimming machine where the cutting means operates in a plane approximately parallel
to the ground
3.103
lawn edge trimmer
grass trimming machine where the cutting means operates in a plane approximately
perpendicular to the ground
3.104
cutting means
mechanism used to provide the cutting action in which one or more cutting elements, cutting
by impact, rotate about an axis normal to the cutting plane
3.105
cutting element
single non-metallic filament line or freely pivoting non-metallic cutter
3.106
cutting head
support system for the cutting element
3.107
cutting means control
device activated by the operator’s hand or finger, for controlling the cutting mean’s movement
3.108
power switch
switch that controls the primary operating means of the trimmer
3.109
no-load
operation of the appliance at rated voltage with new cutting means, extendable monofilament
line being trimmed to the maximum cutting length less 5 mm
4 General requirement
This clause of Part 1 is applicable.
5 General conditions for the tests
This clause of Part 1 is applicable.
6 Classification
This clause of Part 1 is applicable except as follows.
6.1 Replacement:
Appliances shall be of class ll or class lll.
Compliance is checked by inspection and by the relevant tests.

– 10 – 60335-2-91 © IEC:2008
6.2 Addition:
Walk-behind trimmers of class II or with class II parts shall be classified at least as IPX4.
7 Marking and instructions
This clause of Part 1 is applicable except as follows.
7.1 Addition:
Add the following new indents:
− manufacturer’s address or country of origin;
− year of manufacture, in 4 digits.
Add the following new paragraphs:
The following warnings shall be located in easily visible positions, indicating:
WARNING:
– Read instruction manual.
– Keep bystanders away.
Except for walk-behind lawn trimmers with 360 degree guarding, the machine shall also be
marked with the following:
– Wear eye protection.
Mains-operated appliances shall also be marked with the substance of the following:
– Disconnect the mains plug if the cord is damaged or entangled.
Additionally, hand-held lawn trimmers and hand-held lawn edge trimmers shall be marked
with the following:
– Do not expose to moisture.
Marking giving cautionary information shall be located as close as practicable to the relevant
hazard. Such marking shall either be in one of the official languages of the country in which
the appliance is to be sold or the safety signs and symbols according to Annex AA shall be
used. Colours shall be in accordance with ISO 3767-1 and ISO 3767-3 and/or ISO 11684 as
appropriate unless the symbols are cast, embossed or stamped when colours are not
required. If symbols and/or safety signs are used, their significance shall be described in the
instruction manual.
7.12 Addition:
An operator’s manual shall be supplied with the machine. This shall include
a) a repeat of those warnings required to be marked on the appliance together with further
explanation, where appropriate. Where symbols or safety signs are used in the marking on
the appliance, their function shall be explained;
b) instructions for the proper assembly of the appliance for use, if the appliance is not
supplied in a completely assembled form;
c) instructions for proper adjustment and maintenance of the appliance;
d) where parts are consumable, the part number of the replacement shall be specified;
e) instructions on the operation of all controls;

60335-2-91 © IEC:2008 – 11 –
f) advice on the use and type of extension cords to be used (not lighter than required by
25.7);
g) instructions for the safe operation, preparation, maintenance and storage of the appliance
such as those given as an example in Annex EE.
8 Protection against access to live parts
This clause of Part 1 is applicable.
9 Starting of motor-operated appliances
This clause of Part 1 is not applicable.
10 Power input and current
This clause of Part 1 is not applicable.
11 Heating
This clause of Part 1 is applicable except as follows.
11.4 Not applicable.
11.5 Replacement:
The trimmer is operated in still air under normal load operation until a steady state is reached,
the torque being applied is measured. While the torque is maintained, the voltage is then
adjusted to 0,94 times the rated voltage or 1,06 times the rated voltage, whichever is the most
unfavourable.
11.6 Not applicable.
11.7 Replacement:
Appliances are operated until steady conditions are established.
12 Void
13 Leakage current and electric strength at operating temperature
This clause of Part 1 is applicable.
14 Transient overvoltages
This clause of Part 1 is applicable.
15 Moisture resistance
This clause of Part 1 is applicable.

– 12 – 60335-2-91 © IEC:2008
16 Leakage current and electric strength
This clause of Part 1 is applicable.
17 Overload protection of transformers and associated circuits
This clause of Part 1 is applicable.
18 Endurance
This clause of Part 1 is replaced as follows.
18.101 Trimmers shall be so constructed that, in normal use, there will be no electrical or
mechanical failure that might impair compliance with this standard. The insulation shall not be
damaged and contacts and connections shall not work loose as a result of heating, vibrations,
etc.
Moreover, overload protection devices shall not operate under normal running conditions.
Compliance is checked by the test of 18.102.
Immediately after the test, the tool shall withstand an electric strength test as specified
in Clause 15. Connections shall not have worked loose, and there shall be no deterioration
impairing safety in normal use.
18.102 The tool is operated at no-load for 15 h of operation at a voltage equal to 1,1 times
rated voltage, and then for 15 h at a supply voltage equal to 0,9 times rated voltage. The
trimmer may be operated for a number of periods, each period being not less than 7 h.
During this test, the trimmer is maintained according to the instruction manual and replace-
ment of the carbon brushes is allowed.
During these tests, overload protection devices shall not operate.
19 Abnormal operation
This clause of Part 1 is applicable except as follows.
19.7 Not applicable.
20 Stability and mechanical hazards
This clause of Part 1 is applicable except as follows.
20.2 Replacement:
All power driven transmission parts (other than the cutting means) shall be guarded to
prevent the operator's contact with these parts.
The principles set out in ISO 12100-1 shall be followed when developing a guarding system.
All guards shall be either permanently attached, or secured to prevent removal without the
use of tools in accordance with 3.25.1 of ISO 12100-1, or the construction of the appliance

60335-2-91 © IEC:2008 – 13 –
shall be such that it cannot be used without the guard in its guarding position in accordance
with 3.25.4 of ISO 12100-1.
Compliance is checked by inspection.
20.101 Guarding of cutting means
20.101.1 Lawn trimmers
Lawn trimmers shall be guarded on the operator’s side, as a minimum, to the extent shown
in Figure 101.
The radius X of the guard shall not be smaller than the major swept radius of the cutting
head and the guard shall extend beyond the plane of the cutting element by at least 3 mm
for walk-behind lawn trimmers and 10 mm for hand-held lawn trimmers. The guard shall
extend at least 45° from the axis of the handle on the side where the cutting element is
moving away from the operator and at least 90° from the axis of the handle on the side where
the cutting element is moving towards the operator. The vertices of these angles lie on the
axis of the cutting head spindle.
If the guarding is less than a total of 360°, the direction of rotation of the cutting element(s)
shall be marked on the lawn trimmer.
Compliance is checked by inspection and measurement.
20.101.2 Lawn edge trimmers
Lawn edge trimmers shall be guarded, as a minimum, to the extent shown in Figure 102.
The radius X of the guard shall not be smaller than the major swept radius of the cutting
head. The guard shall extend beyond the plane of the cutting element by at least 10 mm.
With the lawn edge trimmer in its normal position of use, the guard shall extend a minimum
of 90° from the vertical towards the ground on the side where the cutting element is moving
upwards and a minimum of 45° from the vertical towards the ground on the side where the
cutting element is moving downwards. The vertices of these angles lie on the axis of the
cutting head spindle.
If the guarding is less than a total of 360°, the direction of rotation of the cutting elements
shall be marked on the lawn edge trimmer.
Compliance is checked by inspection and measurement.
20.101.3 Guarding of cutting means
All guards shall be imperforate and shall be either permanently attached or secured to prevent
removal without the use of tools in accordance with 3.25.1 of ISO 12100-1, or the construction
of the appliance shall be such that it cannot be used without the guard in its guarding position
in accordance with 3.25.4 of ISO 12100-1.
Compliance is checked by inspection.
20.102 Controls
Controls, where the purpose is not obvious to the user, shall have the function, direction and
method of operation clearly identified by a durable marking.
Detailed instructions on the operation of all controls shall be provided in the instruction
handbook.
– 14 – 60335-2-91 © IEC:2008
21 Mechanical strength
This clause of Part 1 is applicable except as follows.
21.1 Replace the second paragraph by the following:
The compliance of cutting means guards is checked by the tests of 21.101 and the
compliance of cutting heads is checked by the tests of 21.102. Other parts of the appliance
are checked by applying blows to the appliance by means of the spring-operated impact test
apparatus described in IEC 60068-2-75.
Replace value of impact in the third paragraph with 1,0 J ± 0,05 J.
21.101 Strength and rigidity of cutting means guard
The mechanical strength and rigidity of the cutting means guard shall be adequate for
normal use.
Before the test, the temperature of the parts to be tested are stabilized to an ambient
temperature of 20 °C ± 3 °C.
Compliance shall be checked by the tests given in 21.101.1, 21.101.2 and 21.101.3.
21.101.1 The rigidity of the cutting means guard is checked by applying a force, at any point,
equivalent to the weight of the lawn trimmer in the most unfavourable direction for 30 s.
During and after the test, the guard shall not distort or have become detached, nor shall it
show any visible cracks. The screws and retaining clips shall still be secure and the
requirements of 21.101.1 and 21.101.2 shall still be met.
21.101.2 The strength of cutting means guards of walk-behind lawn trimmers and walk-
behind lawn edge trimmers is tested by means of a ball impact test.
Each of three samples of the complete appliance is subjected to an impact of 6,5 J ± 0,2 J on
a part of the guard likely to be the weakest, with the trimmer resting on a smooth, rigid, level
surface.
The tests are conducted so that, in each test, the sample receives an impact in a location
different from the other two tests.
The impact is produced with a smooth steel sphere (as used for ball bearings) having a
diameter of 50 mm ± 0,8 mm. If the part to be tested is at an angle of up to 45° to the
horizontal, the sphere is allowed to fall vertically from rest to strike the part. Otherwise, the
sphere is suspended by a cord and is allowed to fall from rest as a pendulum to strike the
part. In either case, the vertical travel of the sphere is to be 1 300 mm ± 3 mm.
After the tests, the guard shall not have become detached nor shall it show any visible cracks.
The screws and retaining clips shall still be secure and the requirements of 20.101.1 and
20.101.2 shall still be met.
21.101.3 The strength of the cutting means guards of hand-held lawn trimmers and hand-
held lawn edge trimmers is tested by means of the following drop test.
One sample of the complete appliance without the supply cord is dropped three times so that
the guard falls through a vertical distance of 900 mm ± 2 mm onto a smooth horizontal
concrete surface in such a manner as to test the guard most severely. A string shall be used

60335-2-91 © IEC:2008 – 15 –
to suspend the appliance so that the desired orientation of the appliance is achieved. Cutting
the string will allow the appliance to fall in the correct orientation to test the guard of the
cutting head (see Figure 103).
After the tests, the guard shall not have become detached nor shall it show any visible cracks.
The screws and retaining clips shall still be secure and the requirements of 20.101.1 and
20.101.2 shall still be met.
21.102 Strength of the cutting head
The mechanical strength of the cutting head shall be adequate for normal use. Before the
test, the temperature of the parts to be tested shall be stabilized to an ambient temperature of
20 °C ± 3 °C.
Compliance shall be checked by the test given below.
One sample of the complete appliance is dropped so that the cutting head, in a horizontal
plane, falls through a vertical distance to make contact with a rigidly supported horizontal
steel block. The drop height is 900 mm ± 2 mm for hand-held lawn trimmers and hand-held
lawn edge trimmers, and 250 mm ± 2 mm for walk-behind lawn trimmers and walk-behind
lawn edge trimmers. A string shall be used to suspend the appliance so that the desired
orientation of the appliance is achieved. Cutting the string will allow the appliance to fall in the
correct orientation to test the cutting head (see Figure 104).
Damage to other parts during this test shall be ignored.
It is not necessary for the appliance to be operable after the test.
If the appliance is operable, then, immediately following the test, the appliance shall be run at
its maximum speed for 30 s both with and without cutting elements.
If the appliance is not operable and the cutting head is not visibly damaged, all parts of the
cutting head that are replaceable by the user and which can be transferred are fitted to a
new appliance. This new appliance is then run at its maximum speed for 30 s both with and
without cutting elements.
No parts shall become detached and no visible cracks shall have developed.
22 Construction
This clause of Part 1 is applicable except as follows.
22.36 Addition:
Hand-held lawn trimmers and hand-held lawn edge trimmers shall have at least one
handle.
All hand-held lawn trimmers and hand-held lawn edge trimmers with a mass of more than
3,5 kg shall have two handles and the distance between the centres of the two handles shall
be at least 250 mm.
This measurement of 250 mm does not apply to two handled lawn trimmers or lawn edge
trimmers with a mass of 3,5 kg or less.

– 16 – 60335-2-91 © IEC:2008
Additionally, all hand-held lawn trimmers and hand-held lawn edge trimmers with a mass
of more than 6 kg shall also have at least a single shoulder harness and those with a mass of
more than 7,5 kg shall have a double shoulder harness.
The mass of the appliance shall be determined in its heaviest condition of normal use as
specified in the instruction manual and without cable or harness.
The gripping surface of any handle required by this standard shall be at least 100 mm long.
If the part containing the motor complies with the 100 mm dimension, it may be considered as
a handle.
The gripping length of a bail or closed loop handle shall comprise any length that is straight or
curved at a radius greater than 100 mm together with any bend radius but not more than
10 mm at either or both ends of the gripping surface.
If a straight handle is supported centrally (i.e. "T" type), the gripping length shall be calculated
as follows:
− for handles with a periphery (not including the support) of less than 80 mm, the gripping
length shall be the sum of the two parts either side of the support;
− for handles with a periphery (not including the support) of 80 mm or more, the gripping
length shall be the complete length from end to end.
Where appropriate, the part of the handle containing the cutting means control actuator
shall be counted as part of the handle gripping length. Finger grip or similar superimposed
profiles shall not affect the method of calculating the handle gripping length.
Compliance is checked by inspection and measurement.
22.40 Replacement:
A cutting means control shall be provided and this shall require two separate and dissimilar
actions before the cutting elements can be driven, or the control shall be guarded to prevent
inadvertent operation. There shall be no means of locking this control in the "on" position and
the movement of the cutting element shall come to rest after the control is released.
Compliance shall be checked by inspection and, for a guarded cutting means control, it
shall not be possible to operate the control by means of a 100 mm ± 1 mm diameter sphere.
22.101 A cutting means shall consist of one or more non-metallic cutting elements mounted
on or emerging from a generally circular cutting head.
Compliance is checked by inspection.
22.102 A cutting element shall consist of one of the following:
a) a non-metallic filament line, or
b) a non-metallic freely pivoting cutter.
Appliances having cutting means using one or more cutting elements of continuous filament
line (e.g. wound on a spool contained either in the cutting head or other attachment) shall
incorporate a means to automatically limit the line to its correct operating length after the line
has been extended and/or the appliance is operated.
The manufacturer shall not supply metallic cutting elements which can replace the
non-metallic ones.
60335-2-91 © IEC:2008 – 17 –
Compliance is checked by inspection.
22.103 A cutting element shall have a kinetic energy of not more than 10 J.
Compliance is checked by inspection, measurement and test. Polyamide cutting elements
are stored for at least seven days in a humidity cab
...