IEC 61300-2-56:2020

IEC 61300-2-56 ®
Edition 1.0 2020-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures –
Part 2-56: Tests – Wind resistance of mounted housing

Dispositifs d’interconnexion et composants passifs fibroniques – Procédures
fondamentales d'essais et de mesures –
Partie 2-56: Essais – Résistance au vent des boîtiers installés

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IEC 61300-2-56 ®
Edition 1.0 2020-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fibre optic interconnecting devices and passive components – Basic test and

measurement procedures –
Part 2-56: Tests – Wind resistance of mounted housing

Dispositifs d’interconnexion et composants passifs fibroniques – Procédures

fondamentales d'essais et de mesures –

Partie 2-56: Essais – Résistance au vent des boîtiers installés

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.20 ISBN 978-2-8322-8731-6

– 2 – IEC 61300-2-56:2020 © IEC 2020
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 General description . 7
5 Apparatus . 8
5.1 Loading method . 8
5.1.1 General . 8
5.1.2 Method for pole-mounted housing . 8
5.1.3 Method for ground-mounted housing . 11
5.2 Force generator . 11
5.3 Force gauge . 12
5.4 Holding fixture . 12
5.5 Force applying device . 12
5.6 Timer . 12
6 Procedure . 12
6.1 General . 12
6.2 Pre-conditioning . 12
6.3 Initial examination . 12
6.4 Mounting DUT . 12
6.5 Conditioning . 13
6.6 Recovery . 13
6.7 Final examination . 13
7 Severity . 13
8 Details to be specified . 14
Annex A (normative) Testing pole-mounted protective housings with vertical load
application . 15
A.1 General . 15
A.2 Method for pole-mounted housing with vertical load application . 15
A.3 Severities . 16
Annex B (informative) Calculation of force resulting from wind load . 17
B.1 Formula of force resulting from wind load . 17
B.2 Example of force calculation . 17
B.3 Calculation of factor for frontal load application of pole-mounted housing . 18
B.4 Calculation of factor for lateral load application of pole-mounted housing . 19
B.5 Calculation of factor for vertical load application of pole-mounted housing . 20
B.6 Calculation of factor for frontal load application of ground-mounted housing . 20
B.7 Calculation of factor for lateral load application of ground-mounted housing . 20
Bibliography . 21

Figure 1 – Dimensions of pole-mounted and ground-mounted housing . 8
Figure 2 – Side view of frontal load application . 9
Figure 3 – Front view of frontal load application . 9
Figure 4 – Side view of lateral load application . 10

Figure 5 – Front view of lateral load application . 10
Figure 6 – Isometric view of frontal load application . 11
Figure 7 – Isometric view of lateral load application . 11
Figure A.1 – Side view of vertical load application . 15
Figure A.2 – Front view of vertical load application . 16
Figure B.1 – Worst-case situation for frontal load application . 18
Figure B.2 – Model with wind load on one side only . 18
Figure B.3 – Model for calculation of F from F . 19
T R
Table 1 – Recommended severity values for pole-mounted housing . 13
Table 2 – Recommended severity values for ground-mounted housing . 14
Table A.1 – Recommended severity value for pole-mounted housing and vertical load
application . 16
Table B.1 – Examples of drag coefficients . 17

– 4 – IEC 61300-2-56:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIBRE OPTIC INTERCONNECTING
DEVICES AND PASSIVE COMPONENTS –
BASIC TEST AND MEASUREMENT PROCEDURES –

Part 2-56: Tests – Wind resistance of mounted housing

FOREWORD
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61300-2-56 has been prepared by subcommittee 86B: Fibre optic
interconnecting devices and passive components, of IEC technical committee 86: Fibre optics.
The text of this International Standard is based on the following documents:
FDIS Report on voting
86B/4300/FDIS 86B/4325/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 61300 series, published under the general title Fibre optic
interconnecting devices and passive components – Basic test and measurement procedures,
can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 61300-2-56:2020 © IEC 2020
INTRODUCTION
Outdoor protective housings are exposed to wind load. The housing fixings should be able to
withstand the force of the wind without damage to or movement of the housing or its fixings.
The method defined in this document provides reproducible conditions for testing the wind
resistance of protective housings and their mounting hardware, either pole-mounted or ground-
mounted, in two different horizontal directions (frontal and lateral). Additionally, the conditions
for optional testing the wind resistance of pole-mounted protective housings in vertical direction
are given.
Depending on the installation and the location, the wind speed can be very different. Even in
the same geographic location, the wind speed can vary considerably with height above the
ground (e.g. at the top of a mast). Recommended severities are included in this document and
considered as a minimum.
Annex A provides reproducible conditions for testing the wind resistance of pole-mounted
protective housings in vertical direction.
Annex B provides information for the calculation of the resulting force on the protective housing
from wind load.
FIBRE OPTIC INTERCONNECTING
DEVICES AND PASSIVE COMPONENTS –
BASIC TEST AND MEASUREMENT PROCEDURES –

Part 2-56: Tests – Wind resistance of mounted housing

1 Scope
This part of IEC 61300 describes the test procedure to test the wind resistance of a protective
housing and its mounting hardware using the fastening parts recommended by the
manufacturer. The protective housing is considered to have a cuboid shape.
The applied force in this test procedure simulates a steady wind load from each direction to a
protective housing and its mounting hardware fixed to a support.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61300-1, Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures – Part 1: General and guidance
IEC 61300-3-1, Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures – Part 3-1: Examinations and measurements – Visual examination
3 Terms and definitions
For the purpose of this document, the terms and definitions given in IEC 61300-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 General description
The device under test (DUT) is a protective housing and its mounting hardware fixed to a
support using the fastening parts recommended by the manufacturer. A force is applied to the
DUT at the specified rate until the required load has been reached. The load shall be applied
during the specified period.
Two different installation types are considered: pole and ground mounting.
The acceptance criteria for the test shall be stated in the relevant specification. Typical failure
modes include cracks, permanent deformation or other damage of the housing and fastening
parts as well as movement of the housing in relation to its initial position on the pole or on the
ground.
– 8 – IEC 61300-2-56:2020 © IEC 2020
This test procedure is intended to simulate the wind load on a protective housing and its
mounting hardware fixed to a pole or on the ground as shown in Figure 1 a) and b) by applying
a force as recommended in Clause 7.
The relevant specification should specify the sequence of load application if the wind resistance
is tested in different directions with the same DUT. The dimensions and the applicable wind
directions for pole-mounted or ground-mounted housings are shown in Figure 1.

a) Pole-mounted housing b) Ground-mounted housing
Key
D depth of the housing
F resultant wind load force
H height of the housing
W width of the housing
Figure 1 – Dimensions of pole-mounted and ground-mounted housing
5 Apparatus
5.1 Loading method
5.1.1 General
The test apparatus shall be capable of applying an axial load to the DUT. For the different
installation situations, pole and ground-mounted housing, separate loading methods are
described in 5.1.2 and 5.1.3.
5.1.2 Method for pole-mounted housing
The DUT shall be mounted to a pole section according to the manufacturer’s recommended
installation instruction and using fixing parts (e.g. brackets, screws, hose clamps, etc.) as
recommended by the manufacturer. All the normal internal components shall be fitted to the
DUT before installation onto the pole. The pole shall be made of material and have a diameter
according to the relevant specification. The pole should have a diameter within the range
specified for the DUT. The DUT shall be tested with frontal or lateral load application as
specified in the relevant specification. Testing with the load application in one direction is

usually sufficient and this should be the direction that gives the highest force to the bracket and
the fixing parts. If required by the relevant specification, testing with vertical load application
shall be done according to the conditions given in Annex A.
For frontal load application, the DUT shall be mounted to the pole and the load is applied on
one side of the DUT via the force gauge as shown in Figure 2 and Figure 3.

Figure 2 – Side view of frontal load application
The variable x in Figure 2 is the distance from the pole axis to the centre of force application.
The outer edge of the contact surface of the force gauge should be aligned closely to the outer
edge of the DUT. Then the distance x shall be determined. The value of x is required to calculate
the applied force (see Table 1).

Figure 3 – Front view of frontal load application
For lateral load application, the DUT shall be mounted to the pole and the axial load is applied
to the DUT via the force gauge as shown in Figure 4 and Figure 5.

– 10 – IEC 61300-2-56:2020 © IEC 2020

Figure 4 – Side view of lateral load application

Figure 5 – Front view of lateral load application
NOTE The method of lateral load application described in 5.1.2 can also be used for a wall mounted housing.

5.1.3 Method for ground-mounted housing
The DUT shall be mounted to the ground according to the manufacturer’s recommended
installation instruction using fixing parts as recommended by the manufacturer. All the normal
internal components shall be fitted to the DUT before attaching it to the ground. The DUT shall
be tested with frontal or lateral load application as specified in the relevant specification and as
shown in Figure 6 and Figure 7. Testing with the load application in one direction is usually
sufficient and this should be the direction that gives the highest force to the housing and fixing
parts.
Figure 6 – Isometric view of frontal load application

Figure 7 – Isometric view of lateral load application
5.2 Force generator
The force generator may be any device or apparatus capable of smoothly applying the specified
force at the specified rate.
– 12 – IEC 61300-2-56:2020 © IEC 2020
5.3 Force gauge
A force gauge having the specified measurement uncertainty shall be used to measure the axial
force applied to the DUT. The contact area between the force gauge and the DUT shall be large
enough such that the load does not significantly deform or damage the DUT. The contact
surface shall be flat, circular and with the edges radiussed and the recommended contact area
is 10 cm but the force gauge contact area shall be enlarged if the box readily deforms.
5.4 Holding fixture
For pole-mounted housing testing, a suitably robust holding fixture shall be used to hold the
pole and the DUT stationary. Care shall be taken in the design and use of the holding fixture to
ensure that it does not apply any compressive forces which might deform or break the DUT.
For ground-mounted housing testing, the ground shall be robust enough to remain stationary
during application of the load.
5.5 Force applying device
For ground-mounted housing testing, a force applying device (strap, cable or similar) is required
to apply the load to the ground-mounted housing in the desired direction. Care shall be taken
to choose a strap, cable or similar having a much higher failure load than the load to be applied
and that the contact area is large enough to avoid significant deformation or damage to the
DUT. Ensure the safety of the whole test setup.
5.6 Timer
A device to measure the total time the force is applied is required.
6 Procedure
6.1 General
Unless otherwise specified, the test shall be performed under standard test conditions and the
DUT shall be subjected to the test procedure according to 6.2 to 6.7. The test shall be performed
with frontal, lateral and/or vertical force application as specified by the relevant specification.
6.2 Pre-conditioning
Unless otherwise specified, pre-condition each DUT for a minimum of 2 h at the standard
atmospheric test conditions specified in IEC 61300-1.
6.3 Initial examination
Visual examination of the DUT shall be done according to IEC 61300-3-1.
6.4 Mounting DUT
Securely mount the DUT to the apparatus as described in 5.1.2 and as shown in Figure 2 and
Figure 3, Figure 4 and Figure 5, or Figure A.1 and Figure A.2 for a pole-mounted housing or as
described in 5.1.3 and as shown in Figure 6 and Figure 7 for a ground-mounted housing. If the
change of the housing’s position is specified in the relevant specification, then mark the initial
position of the housing in reference to the pole or ground.

6.5 Conditioning
Smoothly apply the force at the specified rate up to the specified value and hold for the specified
duration according to the relevant specification. If the relevant specification does not specify a
force value to be applied, then use the recommended severities given in Table 1, Table 2 and
Table A.1.
6.6 Recovery
Remove the force from the DUT and allow the DUT to recover under standard atmospheric test
conditions for a minimum of 1 min without any load, as defined in IEC 61300-1, unless otherwise
specified in the relevant specification.
6.7 Final examination
If the change of the housing’s position is specified in the relevant specification, visually examine
the position of the housing in relation its initial position on the pole or on the ground before the
conditioning commenced.
If other load applications in different directions to the same DUT are specified by the relevant
specification, then perform the mounting of the DUT, the conditioning and the recovery as
detailed in 6.4 to 6.6.
Remove the DUT from the test apparatus and allow the DUT to recover under standard
atmospheric test conditions for a minimum of 1 min, as defined in IEC 61300-1, unless
otherwise specified in the relevant specification.
Unless otherwise specified, visually examine the DUT, the bracket of the DUT (if present) and
the fastening parts in accordance with IEC 61300-3-1. Check for evidence of cracking,
permanent deformation or other damage which might impair its function, and against any other
pass/fail criteria specified in the relevant specification.
7 Severity
The severity of the test is dependent upon the magnitude of the force and to a lesser extent to
the rate of application and duration at the specified load. The magnitude, rate of application
and duration at the specified load shall be given in the relevant specification. The recommended
values for the test parameters are given in Table 1 and Table 2. See Annex B for the calculation
of force resulting from wind load.
Table 1 – Recommended severity values for pole-mounted housing
a b, c
Direction of load Rate of application Minimum duration
Category Applied force
application
N N/s s
A Frontal 5 5
150 × W × H / x
Lateral 1 150 × D × H 5 5
NOTE For recommended severities for vertical direction of load application, see Table A.1.
a
The performance category is defined in IEC 61753-1.
b 3
A drag coefficient of 1,1, a density of air of 1,2 kg/m and a wind speed of 41,7 m/s are included in the factor
for the calculation of the applied force. See Clause B.3 and Clause B.4 for the calculation of the formula for
the resulting forces by wind load.
c
Values for parameter D, H, W and x in m.

– 14 – IEC 61300-2-56:2020 © IEC 2020
Table 2 – Recommended severity values for ground-mounted housing
a b, c
Direction of load Rate of application Minimum duration
Category Applied force
application
N N/s s
A Frontal 500 × W × H 5 5
Lateral 500 × D × H 5 5
a
The performance category is defined in IEC 61753-1.
b 3
A drag coefficient of 1,1, a density of air of 1,2 kg/m and a wind speed of 27,8 m/s are included in the factor
for the calculation of the applied force. See Clause B.6 and Clause B.7 for the calculation of the formula for
the resulting forces by wind load.
c
Values for parameter D, H and W in m.

If the housing is not a cuboid shape, then the profile of its projected cross-sectional area in the
direction of the wind should be reduced to a representative rectangular area and noted in the
report.
8 Details to be specified
The following details, as applicable, shall be specified in the detail specification:
a) direction of load application (frontal, lateral or vertical);
b) sequence of load application in different directions to the same DUT;
c) dimension(s), material and type of pole or ground;
d) applied force (and tolerance) and its rate of application;
e) duration of the applied force;
f) criteria for the initial examination;
g) criteria for the final examination;
h) criteria for the change of the housing’s position in relation to its initial position;
i) additional pass/fail criteria;
j) deviations from the test procedure.

Annex A
(normative)
Testing pole-mounted protective housings with vertical load application
A.1 General
Vertical wind speed to pole-mounted housings is typically lower than horizontal wind speed.
Therefore, testing protective housings with vertical load application shall be done if the relevant
specification require it mandatorily.
A.2 Method for pole-mounted housing with vertical load application
For vertical load application, the DUT shall be mounted to the pole and the axial load is applied
to the DUT via the force gauge as shown in Figure A.1 and Figure A.2.

Figure A.1 – Side view of vertical load application

– 16 – IEC 61300-2-56:2020 © IEC 2020

Figure A.2 – Front view of vertical load application
A.3 Severities
The severity of the test is dependent upon the magnitude of the force and to a lesser extent to
the rate of application and duration at the specified load. The magnitude, rate of application
and duration at the specified load shall be given in the relevant specification. The recommended
value for the test parameters is given in Table A.1.
Table A.1 – Recommended severity value for pole-mounted
housing and vertical load application
a b, c
Direction of load Rate of application Minimum duration
Category Applied force
application
N N/s s
A Vertical 500 × W × D 5 5
a
The performance category is defined in IEC 61753-1.
b 3
A drag coefficient of 1,1, a density of air of 1,2 kg/m and a wind speed of 27,8 m/s are included in the factor
for the calculation of the applied force. See Clause B.5 for the calculation of the formula for the resulting forces
by wind load.
c
Values for parameter D and W in m.

Annex B
(informative)
Calculation of force resulting from wind load
B.1 Formula of force resulting from wind load
The test procedure in this document is applicable to simulate wind resistance from one direction
at a time.
The resulting force (F) caused by wind load can be calculated as:
F = c × ρ × v / 2 × A (B.1)
d 0 p
where
c is the drag coefficient, depending on the shape of DUT (see Table B.1);

d
ρ is the air density (approx. 1,2 kg/m at sea level and at +20 °C);
v is the wind velocity;
A is the projected cross-sectional area facing the direction of the wind.
p
Table B.1 – Examples of drag coefficients
Shape Conditions C value
d
Rectangular plate l / a = 1
1,1
l / a = 2 1,15
l / a = 4 1,19
Cube - 1,1
B.2 Example of force calculation
Situation:
Box with a cubic form and a side length of 0,2 m; 41,7 m/s (150 km/h or 93,2 mph) wind speed;
at sea level and +20 °C; lateral wind load direction.

– 18 – IEC 61300-2-56:2020 © IEC 2020
Calculation of the resultant force F using Formula (B.1) and replacing A with D × H:
p
v = 41,7 m/s; c = 1,1; ρ = 1,2 kg/m ;
0 d
2 3 2 2 2
F = c × ρ × v / 2 × D × H = 1,1 × 1,2 kg/m × 41,7 m /s / 2 × 0,2 m × 0,2 m = 45,9 N

d 0
NOTE A wind speed of 150 km/h equals force 12 on the Beaufort wind scale and represents a hurricane force.
B.3 Calculation of factor for frontal load application of pole-mounted housing
A wind aimed directly at the complete surface area of the housing from the front or back side
was not considered to be the most critical case. The "worst-case" was considered to occur when
one side of the housing is protected from the wind load by the pole, or by any other object, as
shown in Figure B.1, creating maximum torque.

Figure B.1 – Worst-case situation for frontal load application
For simplification, wind load on one side only of the housing is assumed resulting in force F
R
as shown in Figure B.2.
Figure B.2 – Model with wind load on one side only
Calculation of the resulting force F using Formula (B.1) and replacing A with W × H / 2 for half
R p
of the projected cross-sectional area:
F = c × ρ × v / 2 × W × H / 2 (B.2)

R d 0
Figure B.3 – Model for calculation of F from F
T R
The parameter x in Figure B.3 is the distance from the pole axis to the centre of the force
application (see also Figure 2). The distance x should be determined when the test set-up is
done and its value is required for calculation of the applied force.
Calculation of the test force F with lever rule as shown in Figure B.3:
T
F = F × W / 4 / x (B.3)
T R
Calculation of F using Formula (B.3) and replacing F with the terms in Formula (B.2):
T R
F = c × ρ × v / 2 × W × H / 2 × W / 4 / x (B.4)
T d 0
2 3
Calculation of c × ρ × v / 2 / 2 / 4 with v = 41,7 m/s, c = 1,1 and ρ = 1,2 kg/m :
d 0 0 d
2 3 2 2 2 2 2
c × ρ × v / 2 / 2 / 4 = 1,1 × 1,2 kg/m × 41,7 m /s / 2 / 2 / 4 = 143 N/m ≈ 150 N/m
d 0
Replacing the rounded result of c × ρ × v / 2 / 2 / 4 in Formula (B.4) gives:
d 0
F ≈ 150 × W × H / x (B.5)
T
NOTE The resulting Formula (B.5) was used in Table 1 as the factor for the calculation of the applied force for
frontal load application.
B.4 Calculation of factor for lateral load application of pole-mounted housing
Calculation of F using Formula (B.1), replacing A with D × H:
T P
v = 41,7 m/s; c = 1,1; ρ = 1,2 kg/m ;
0 d
2 3 2 2 2 2
F = c × ρ × v / 2 × D × H = 1,1 × 1,2 kg/m × 41,7 m /s / 2 × D × H = 1 146 N/m × D × H
T d 0
F ≈ 1 150 N/m × D × H (B.6)
T
NOTE The resulting Formula (B.6) was used in Table 1 as the factor for the calculation of the applied force for
lateral load application.
– 20 – IEC 61300-2-56:2020 © IEC 2020
B.5 Calculation of factor for vertical load application of pole-mounted housing
Calculation of F using Formula (B.1), replacing A with W × D:
T P
v = 27,8 m/s; c = 1,1; ρ = 1,2 kg/m ;
0 d
2 3 2 2 2 2
F = c × ρ × v / 2 × W × D = 1,1 ×1,2 kg/m × 27,8 m /s / 2 × W × D = 509 N/m × W × D
T d 0
F ≈ 500 N/m × W × D (B.7)
T
NOTE The resulting Formula (B.7) was used in Table A.1 as the factor for the calculation of the applied force for
vertical load application.
B.6 Calculation of factor for frontal load application of ground-mounted
housing
Calculation of F using Formula (B.1), replacing A with W × H:
T P
v = 27,8 m/s; c = 1,1; ρ = 1,2 kg/m ;
0 d
2 3 2 2 2 2
F = c × ρ × v / 2 × W × H = 1,1 × 1,2 kg/m × 27,8 m /s / 2 × W × H = 509 N/m × W × H
T d 0
F ≈ 500 N/m ×W × H (B.8)
T
NOTE The resulting Formula (B.8) was used in Table 2 as the factor for the calculation of the applied force for
frontal load application.
B.7 Calculation of factor for lateral load application of ground-mounted
housing
Calculation of F using Formula (B.1), replacing A with D × H:
T P
v = 27,8 m/s; c = 1,1; ρ = 1,2 kg/m ;
0 d
2 3 2 2 2 2
F = c × ρ × v / 2 × D × H = 1,1 × 1,2 kg/m × 27,8 m /s / 2 × D × H = 509 N/m × D × H
T d 0
F ≈ 500 N/m × D × H (B.9)
T
NOTE The resulting Formula (B.9) was used in Table 2 as the factor for the calculation of the applied force for
lateral load application.
Bibliography
IEC 61753-1, Fibre optic interconnecting devices and passive components – Performance
standards – Part 1: General and guidance

___________
– 22 – IEC 61300-2-56:2020 © IEC 2020
SOMMAIRE
SOMMAIRE . 22
AVANT-PROPOS . 24
INTRODUCTION . 26
1 Domaine d'application . 27
2 Références normatives . 27
3 Termes et définitions . 27
4 Description générale . 27
5 Appareillage . 28
5.1 Méthode de charge . 28
5.1.1 Généralités . 28
5.1.2 Méthode pour un boîtier installé sur un poteau . 28
5.1.3 Méthode pour un boîtier installé au sol . 31
5.2 Générateur de force . 31
5.3 Dynamomètre . 32
5.4 Dispositif de maintien . 32
5.5 Dispositif d'application de la force . 32
5.6 Minuteur . 32
6 Procédure . 32
6.1 Généralités . 32
6.2 Préconditionnement . 32
6.3 Examen initial . 32
6.4 Montage du DUT . 32
6.5 Conditionnement . 33
6.6 Rétablissement . 33
6.7 Examen final . 33
7 Sévérité . 33
8 Eléments à spécifier . 34
Annexe A (normative) Essais de boîtiers de protection installés sur un poteau avec
application de charge verticale . 35
A.1 Généralités . 35
A.2 Méthode pour des boîtiers installés sur un poteau avec application de
charge verticale . 35
A.3 Sévérités . 36
Annexe B (informative) Calcul de la force résultant de la charge du vent . 37
B.1 Formule de la force résultant de la charge du vent . 37
B.2 Exemple de calcul de la force .
...