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Requirements for External Lightning Protection Components

The mechanical properties have to be tested and observed. The quality Test scope for insulated conductors
of coating (smooth, continuous) as well as the minimum thickness and • High voltage test for proving the electric strength of the insulated
adhesion to the base material are important and have to be tested par- conductor (proof of dielectric strength); and as a system test
ticularly if coated materials such as galvanised steel (St/tZn) are used. (see Figure 6)
• Test for lightning current carrying capability of the insulated conductor
This is described in the standard in the form of a bending test. For this according to the specifications of IEC 62561-1 with a test impulse in
purpose, a specimen is bent through a radius equal to 5 times its diam- accordance with the manufacturer’s classification of IEC TS 62561-8
eter to an angle of 90°. In doing so, the specimen may not show sharp Edition 1.0 2018-01
edges, breakage or exfoliation. Moreover, the conductor materials shall
be easy to process when installing lightning protection systems. Wires or Test scope for conductor holders
strips (coils) are supposed to be easily straightened by means of a wire • Axial tensile force (mounted conductor, holder distance 250 mm, axial
straightener (guide pulleys) or torsion. Furthermore, it should be easy to tensile load 50 N)
install / bend the materials at structures or in the soil. These standard re- • Bending test (mounted conductor, holder distance 250 mm, vertical
quirements are relevant product features which have to be documented tensile load 200 N, time depends on type of holder)
in the corresponding product data sheets of the manufacturers.

Earth electrodes / earth rods
The separable DEHN earth rods are made of special steel and are com-
pletely hot-dip galvanised or consist of high-alloy stainless steel (StSt
(V4A); material No. 1.4571). A coupling joint which allows connection
of the rods without enlarging the diameter is a special feature of theses
earth rods. Every rod provides a bore and a pin end.
EN 62561-2 specifies the requirements for earth electrodes such as mate-
rial, geometry, minimum dimensions as well as mechanical and electrical
properties. The coupling joints linking the individual rods are weak points.
For this reason, EN 62561-2 requires that additional mechanical and elec-
trical tests be performed to test the quality of these coupling joints.
For this test, the rod is put into a guide with a steel plate as impact area.
The specimen consists of two joined rods with a length of 500 mm each.
The top end of the specimen is impacted by means of a vibration hammer
with an adequate hammer insert for a duration of two minutes. The blow
rate of the hammer must be 2000 ± 1000 min and the single stroke
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impact energy must be 50 ± 10 [Nm]. Figure 6: High voltage test according to IEC TS 62561-8 Edition 1.0
If the couplings have passed this test without visible defects, they are 2018-01 of a HVI system with four HVI Conductors.
subjected to artificial ageing by means of salt mist and humid sulphurous
atmosphere treatment. Then the couplings are loaded with three light- Insulated spacers – DEHNiso spacers
ning current impulses of 10/350 μs wave form of 50 kA and 100 kA each. When testing insulated spacers, one differentiates between the way they
The contact resistance (measured above the coupling) of steel earth rods are mounted: self-supporting components (spacer in a concrete base)
must not exceed 1 mΩ (stainless steel 3 mΩ). To test whether the cou- and horizontally mounted holders (air-termination rod with spacer). Be-
pling joint is still firmly connected after being subjected to this lightning fore mechanical and electrical testing, the specimens must pass a UV
current load, the coupling force is tested by means of a tensile testing light and a corrosion test.
machine.
Scope of mechanical test
Testing of insulated conductors and spacers • Bending test (length to specimen 500 mm, min. load 10 N, min. 60 min)
In accordance with the new component standard IEC TS 62561-8 Edition • Impact test centred (length of specimen 500 mm, force 2 J)
1.0 2018-01, in future also insulated conductors including system com- • Tensile force (length of specimen 500 mm, tensile force 200 N)
ponents as well as insulated spacers (GRP) must be tested mechanically
as well as electrically. The tests differ according to the type of product. Scope of electrical test
For the electrical testing, high voltage is applied on the set-up. Insulated

Insulated conductors – HVI Conductors spacers must have a dielectric strength in accordance with standard re-
A high-voltage-resistant insulated conductor (HVI Conductor) as well as quirements of IEC TS 62561-8 Edition 1.0 2018-01.

the corresponding mounting material must, in compliance with IEC TS
62561-8 Edition 1.0 2018-01, be able to insulate and safely discharge Test according to IEC TS 62561-8 Edition 1.0 2018-01 at DEHN
lightning currents. Mechanical loads and environmental influences are DEHN products for isolated lightning protection are designed for the
also considered. Therefore both, UV light tests and corrosion tests are requirements according to IEC TS 62561-8 Edition 1.0 2018-01.
also required in the component standard.
General note!
Using components and devices which have been tested in com-
pliance with the latest standards is a basic prerequisite for a
functional lightning protection system. Installers of lightning
protection systems must select components according to the re-
quirements at the installation site and install them in accordance
with the manufacturers’ specifications. In state-of-the-art light-
ning protection technology, it is important to consider and comply
with electrical criteria in addition to mechanical requirements.

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