IEC 61914

Explanatory Notes to IEC 61914 – Cable Cleats for Electrical Installations

1. Requirements of the manufacturer

The IEC 61914 requires from the manufacturer of the Cable Clamps type tests of
mechanical and electro-dynamic properties, of UV and corrosion resistance, and
flame tests. These type tests must be performed by an accredited testing institute.

Cable Clamps certified according to this standard must be designed and manufactured
to guarantee a safe handling and safe fastening for wires / cables in accordance
with the below classification as given by the manufacturer.

The tests are performed on specific clamps of each series, whereby the clamps are
classified according to various characteristics.

2. Classification (Paragraph 6 of the standard)

Material (6.1)

Metallic 6.1.1

Non-metallic 6.1.2

Composite 6.1.3

Temperature (6.2)

Minimum temperature

Maximum temperature

Resistance to impact (6.3)

Very light 6.3.1

Light 6.3.2

Medium 6.3.3

Heavy 6.3.4

Very heavy 6.3.5

Type of retention (6.4)

With lateral retention 6.4.1
– in x-direction
– in y-direction

With axial retention 6.4.2

Resistant to electro-magnetical forces (short circuits):

Withstanding one short circuit 6.4.3

Withstanding more than one short circuit 6.4.4

Reaction to environmental influences (6.5)

UV-light*1 6.5.1

Corrosion / salt spray test*2 6.5.2

Declared

Not declared

Low

High

Flame propagation (10.1)

Not passed

Passed

Inductive heating (12.2)

Declared*3

*1 only for non-metallic and composite components
*2 only for metallic and composite components
*3 only for ferromagnetic components

3. Marking of the clamps

Furthermore, a marking of the Cable Clamps and a documentation (7) of the results
is required by the IEC 61914.

The marking shall provide following information (7.1):

Manufacturer’s or vendor’s
name / logo / Trademark
Product
identification / typ

Hereby the marking must be durable and easily legible (7.2).

With the design and manufacturing of Cable Clamps it has to be ensured that the Cable Clamps are free
of sharp edges, burrs, etc., to avoid damage to the cables and / or conductors and to avoid injury of
the assembly staff and operators (8).

4. Required tests for the classification

4.1 Mechanical tests

All mechanical tests are carried out respectively on three samples of the smallest
and largest clamp of a series.

Impact test (9.2)

The impact test serves to prove the manufacturer’s specified minimum operating
temperature and impact strength of the clamp.
Impact tests on non-metallic and composite clamps are carried out after pre-conditioning
in an UV-chamber for 700 hours (29 days) at the minimum permanent application
temperature as specified by the manufacturer.

Minimum Temperature
(°C)
+5
–5
–15
–25
–40
–60

On metallic clamps, the impact test is carried at ambient temperature. The impact energy
of the hammer is indicated according to the classification in the following table:

Classification

Impact energy
(J)
Equivalent mass
(kg)
Height
(mm)

Very light

0,50,25200
Light1,00,25400
Medium2,00,5400
Heavy5,01,7300
Very Heavy20,05,0400


After testing, the Cable Clamps must not have any signs of destruction, no breakage or damage
must be visible. If in doubt, lateral load tests (9.3) have to be carried out with these Cable Clamps.

Documentation to be specified by the manufacturer:
The achieved classification for each series at the minimum permanent application
temperature must be documented by the manufacturer in his documentation
(if necessary, with an explanation of the torques of the fixing screws).

4.1.2 Lateral load test (9.3)

The lateral load tests serve to demonstrate the manufacturer’s specified maximum operating temperature
and the maximum lateral restraining forces (N) of the clamps of each series.

These tests must be performed on non-metallic and composite clamps with the maximum permanent
application temperature as specified by the manufacturer.

 

On metallic Cable Clamps the tests are carried out at ambient temperature.

The lateral load test is carried out with test mandrels, representing the smallest possible cable diameter
for each clamp. The lateral load test is carried out in two directions:

Maximum Temperature
(°C)

+ 40
+ 60
+ 85
+ 105
+ 120

Experiment testing the lateral load in x-direction

Experiment testing the lateral load in y-direction

Non-metallic and composite Cable Clamps must hold the maximum load (N) for 60 minutes.
Metallic clamps must hold the load for 5 minutes.
The maximum movement of the mandrels must be less than 50 % of the mandrel diameter.

The maximum lateral restraining forces (N) for each series at the maximum permanent
application temperature are to be documented by the manufacturer  in his documents
(if necessary, with an explanation of the torques of the mounting screws).

4.1.3 Axial load test (9.4)

The axial load tests serve to demonstrate the manufacturer’s specified maximum operating
temperature and the maximum axial restraining forces (N) of the clamps of each series.

These tests must be performed on non-metallic and composite clamps with the maximum
permanent application temperature as specified by the manufacturer.

Maximum Temperature
(°C)
+ 40
+ 60
+ 85
+ 105

+ 120

Experiment testing the axial load

Clamps of all materials must hold the maximum load (N) for 5 minutes.
After the test the axial displacement of the mandrel with respect to the clamp must not exceed 5 mm.

Documentation to be specified by the manufacturer:
The maximum axial restraining forces (N) for each series at the maximum permanent
application temperature are to be documented by the manufacturer in his documents
(if necessary, with an explanation of the torques of the mounting screws).

4.2 Electrodynamic tests

4.2.1 Test for resistance to electromechanical forces (9.5)

The short circuit tests serve to demonstrate the manufacturer’s specified maximum dynamic short circuit
resistance of the clamps of each series.
The short circuit tests are carried out on one type of each series.

Bundling clamps with security clamps

Single clamps with security clamps

îd-Technik Cable Clamps for trefoil formation before the test

îd-Technik Cable Clamps for single formation before the test

 

At a cable section with five clamp positions at equal intervals (D) the following
arrangements are distinguished:

Three cables in trefoil formation with bundling clamp:

Three cables in parallel arrangement with single clamps:

For each arrangement the test must be carried out with a three-phase short-circuit
at the peak shortcircuit current (ip) as specified by the manufacturer.

One end of the cable route is connected to a three-phase power supply and
the other end to a threephase short-circuiting busbar.

The maximum force on the conductor is given by:

 

F = maximum force on the conductor (N/m)
ip = peak short-circuit current (kA)
s = cable centre-line distance (m)

The peak short-circuit current (ip) as specified by the manufacturer is given by:

 

 

Fs = maximum dynamic force on the clamp (N)
D = maximum distance between two neighbouring clamps (m)

Remark:
When determining the distance between two clamps (D), it is essential
to ensure that the maximum allowable buckling of the cables according
to the cable manufacturer in case of short circuit is not exceeded!
In order to represent realistic values for the user, the manufacturer should
perform the short-circuit tests with practical values for the distance between
two clamps and short-circuit current.

 

The classification distinguishes between clamps that withstand one short-circuit (6.4.3) or multiple short-circuits (6.4.4).

Resistant to one short-circuit (6.4.3)

Cable Clamps for trefoil formation after the 1st test

Cable Clamps for single formation after the 1st test

After the short-circuit test:
• there must be no failure that affects the intended function of the Cable Clamp of keeping the cables in place
• the Cable Clamps must be intact without damage
• there must be no damage or cuts to the insulation of the cable

Resistant to more than one short-circuit (6.4.4)

After the first short-circuit, with no damage to the cables or clamps, a second test is performed on the same arrangement with the same peak short-circuit current.
After this test the clamps and cables have to meet the same requirements.
With 1 kV-cables a voltage withstand test is carried out.

Documentation to be specified by the manufacturer (7.3)
• peak short-circuit current ip (kA)
• symmetrical short-circuit current i“k (kA)
• outer diameter of the cables used in the test (m)
• cable centre-line distance S (m)
• maximum distance between two clamps D (m)

Remark:
To save the user consuming calculations to determine the carrying capacity of the clamp, the
maximum allowable dynamic short circuit strength (N) of the clamps (FS) and the torques of the
fixing screws should be specified by the manufacturer.

4.3 Flame propagation test (10)

The flame propagation test serves to demonstrate the flame resistance of the material.

Test of flame resistance
The Cable Clamps are exposed for 30 seconds to a fire test with the needle flame (10.1).
There must be no flame and no embers or no flaming 30 seconds after removal of the needle flame.
Furthermore, the tissue paper may not ignite.

Documentation to be specified by the manufacturer:
The manufacturer must document in his records, whether the Cable Clamps are resistant to flame or not.

4.4 Test of reaction to environmental influences (11)

4.4.1 Test of resistance to ultraviolet light (11.1)

The UV-test serves to demonstrate the UV-resistance of the material.
The smallest and largest Cable Clamps of each series are irradiated for 700 hours (29 days) under the conditions described in IEC §11.1 with UV light.
After UV exposure, the Cable Clamps must not show any signs of destruction, breakage or damage.
Subsequently, the clamps must pass the impact test (9.2) at the minimum permanent application temperature as specified by the manufacturer.

Documentation to be specified by the manufacturer:
The manufacturer must document in his records, whether the Cable Clamps are UV-resistant or not.

4.4.2 Test of resistance to corrosion (11.2)

The test of resistance to corrosion serves to demonstrate the resistance to corrosion of the material.
Metallic and composite Cable Clamps must have adequate resistance to corrosion and salt spray. The respective tests are describes in the standard at 11.1 und 11.2.
For non-metallic Cable Clamps these tests are not necessary.

Documentation to be specified by the manufacturer:
The manufacturer must document in his records, whether the Cable Clamps are resistant to corrosion or not.

4.5 Test of inductive heating (12.2)

With the use of ferromagnetic materials, there is the danger of inductive heating of the cable due to eddy currents.

Documentation to be specified by the manufacturer:
The manufacturer shall apply an appropriate warning.