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LED mast lights for street, walkway and open space lighting previously used high-pressure lamps are damaged while the
are mounted at light point heights of several metres to ensure LED drivers, their parameterisation devices and the LEDs of
a large field of illumination. This, however, is only possible if today’s LED mast lights entail high costs. Although amortisa-
the luminous flux of the light source is sufficiently high which tion is to be expected over a transparent time frame due to
is no problem for today’s highly efficient LEDs. Their long ser- the long service life of LED mast lights, the question arises
vice life, a low temperature sensitivity and individual settings whether the manufacturer accepts the warranty for the over-
of different scenes make them cost-effective and environmen- all system (LED drivers and LEDs) since surges negatively af-
tally-friendly. fect the system-specific service life. The lighting industry has
LED mast lights stand out due to the following special char- already responded to this with a higher dielectric strength of
acteristics: the LED drivers and an impulse current withstand capability
¨ High luminous efficacy up to 110 Im/W of 2 kA and a dielectric strength of 4 kV for new LED mast
¨ The light distribution can be easily adapted to the relevant lights, however, the impulse currents and surges occurring in
illumination task by using different lenses the mains can exceed these values many times over. It has to
¨ Different light colours / colour temperatures be particularly observed that the dielectric strengths L to N
considerably differ from that of L/N to PE.
¨ LEDs have a service life between 50,000 and 100,000 h A metal mast in conjunction with a metal LED mast light mini-
depending on the operating current mises the probability of field-based injection. Consequently,
¨ The temperature-dependent luminous flux of the LEDs var- only surges extending over the cable network must be consid-
ies only slightly and is e.g. 115 % at -30 °C and 95 % at ered. To this end, a surge arrester can be installed in the ter-
40 °C minal compartment / distributor of the mast (Figure 9.15.1).
¨ Individual scenes (e.g. luminous flux, operating times, dusk
dependence) can be pre-set via the LED drivers
¨ In some cases, individual scenes can be set via a 1 – 10 V or
DALI interface
¨ LEDs are ideally suited for safety lighting systems due to
their high luminous flux without switch-on delay
In practice, different LED mast lights are used. All fixture bod-
ies are typically made of metal independent of whether LED
mast lights with “double or reinforced insulation” (previously
class II) or “automatic disconnection of supply” (previously
class I) as per IEC 60364-4-41 (HD 60364-4-41) are used. The
metal housing of the LED mast light dissipates the resulting
heat loss over a large area.
The mast frequently consists of metal and the supply volt-
age flows through a buried cable into the mast. A terminal
compartment that can be opened using tools is situated in the
lower section of small masts. A rubber hose which is relieved
of any strain on both ends connects the terminal compartment
with the mast light. This terminal compartment houses the ter-
minals and the overcurrent protective device. Large masts are
fitted with a supply distributor and, if this distributor feeds the Surge protective device Part No.
mains and equivalent power supply, it is physically divided ac-
cording to the relevant normative requirements. DEHNguard DG M TT 275 or 952 310
If LED mast lights or PVC masts are used, electrostatic charge DEHNguard DG M TNS 275 952 400
must be observed. This, however, will not be described here. DEHNguard DG M TT 2P 275 or 952 110
DEHNguard DG M TN 275 952 200
If you compare the surge-related replacement costs of previ- Figure 9.15.1 Surge arrester installed in the terminal compartment /
ously used mast lights with high-pressure lamps with the re- distributor of the metal mast for protecting the metal
placement costs of today’s LED mast lights, it can be seen that LED mast light from conducted surges caused by
the illuminant, ignition device and inductive control unit of the distant atmospheric events and switching operations

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