Explanatory Notes to IEC 61914 – Cable Cleats for Electrical Installations
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.
Resistance to impact (6.3)
Very light 6.3.1
Very heavy 6.3.5
Type of retention (6.4)
With lateral retention 6.4.1
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)
Corrosion / salt spray test*2 6.5.2
Flame propagation (10.1)
Inductive heating (12.2)
*1 only for non-metallic and composite components
*2 only for metallic and composite components
*3 only for ferromagnetic components
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
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).
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.
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:
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.
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.
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 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.
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.
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).
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
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)
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.
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.
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.