White PaperSurge protection for CCTV systems

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Contents

Camera connected to a build-ing with external lightning protection system with lightning current carrying surge protective devices on both ends

Camera connected to a build-ing without external lightning protection system with surge protective devices on both ends

IP camera with surge protective devices on both ends

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White Paper Surge protection for CCTV systems

WP007/E/0814 © Copyright 2014 DEHN + SÖHNE

cable. Coaxial cables are used for unbalanced transmission, in other words the video signal is transmitted through the core of the coaxial cable (inner conductor). The shield (earth) is the reference point for signal transmission. Balanced transmission (baluns) where the coaxial signal is converted to a two-wire signal is used for two-wire cables.The voltage supply cable is often routed separately. In case of IP cameras, however, a single cable is used for the transmis-sion of the video signal and for voltage supply. An RS 485 bus controls the panning and tilting of the camera.

CCTV systems are used in all areas for access control and facili-ty supervision. In the following, surge protection measures will be described which meet the high availability requirements of CCTV systems.A CCTV system consists of at least one camera, one monitor and one suitable video transmission path. Remotely controlled camera stations are typically equipped with a pan / tilt head which allows the operator to individually adjust the position and perspective of the station. In the simplest case, the transmission line between the junc-tion box and the monitor is a coaxial or a balanced two-wire

cameracamera

pan / tilt head

pan / tilt head

230 V cable

monitorcontrolboard

air-termination rod

MEB

RS 485 cable

short steel mast

coaxial or two-wire cable

junction box

junction box

Figure 1 Camera connected to a building with external lightning protection system with lightning current carrying surge protective devices on both ends

camera

pan / tilt head

pan / tilt head

junction box

coaxial or two-wire cable

RS 485 cable230 V cable

camera monitor controlboard

junction box

Figure 2 Camera connected to a building without external lightning protection system with surge protective devices on both ends

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White Paper Surge protection for CCTV systems

Building with external lightning protection systemFigure 1 shows a CCTV camera installed at a mast. A direct lightning strike to the camera can be prevented if an air-termi-nation rod is installed at the mast. The connecting cable be-tween the junction box and the camera is typically installed in

the metal mast. If this is not possible, the camera cable must be routed in a metal tube and conductively connected to the mast. In this case, surge protective devices do not have to be installed in the junction box if the cable length does not ex-ceed some metres.Lightning equipotential bonding must be established at the entrance point into the building for all cables mentioned above which are routed from the junction box at the mast to a build-ing with external lightning protection system (Table 1).If cameras are mounted on the outer façade of a building, it should be ensured that the camera is located in the protected volume or is protected from direct lightning strikes by an air-termination system.

Building without external lightning protection systemIn case of buildings without external lightning protection sys-tem it is assumed that the risk of damage resulting from a direct or nearby lightning strike to the building is low and thus acceptable. In this case, surge arresters provide sufficient pro-tection (Table 1).Figure 2 shows a multi-line CCTV system and Figure 3 a digital IC camera system.

IP camera

junction box

junction box

LAN cabel

camera PC

Figure 3 IP camera with surge protective devices on both ends

Table 1 Surge protective devices shown in Figures 1 – 3

No. Protection for… Surge protective device Part No.

Surge protective devices for information technology systems

Two-wire cable (video transmission)BLITZDUCTOR XT / BLITZDUCTOR SP + BXT BAS

920 271 / 926 271 920 300

Coaxial cable (video transmission system)UGKF BNC orDGA BNC VCID

929 010909 711

RS 485 cable (camera controller)BLITZDUCTOR XT / BLITZDUCTOR SP + BXT BAS

920 271 / 926 271 920 300

LAN cable (IP camera)DPA M CLE RJ45B 48DPA M CAT6 RJ45S 48

929 121929 100

Surge protective devices for power supply systems – Surge arresters

Three-phase TN system Three-phase TT system

DEHNguard DG M TN 275DEHNguard DG M TT 2P 275

952 200952 110

Surge protective devices for power supply systems – Combined arresters

a.c. TN systema.c. TT system

DEHNshield DSH TN 255DEHNshield DSH TT 255

941 200941 110

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White Paper Surge protection for CCTV systems

WP007/E/0814 © Copyright 2014 DEHN + SÖHNE

UGKF

Type UGKF BNC

Part No. 929 010

SPD class T

Nominal voltage (UN) / Nominal current (IL) 5 V / 0.1 A

Max. cont. operating voltage (d.c.) (Uc) 8 V

C2 Nominal discharge current (8/20 µs)per line / shield-PG (In)

2.5 kA / 10 kA

Test standards IEC 61643-21 / EN 61643-21

DEHNgate

Type DGA BNC VCID

Part No. 909 711

SPD class T

Nominal voltage (UN) 5 V

Max. cont. operating voltage (d.c.) (Uc) 6.4 V

D1 Lightning impulse current (10/350 µs) (Iimp) 1 kA

C2 Nominal discharge current (8/20 µs) shield-PG / line-shield (In)

10 kA / 5 kA

Voltage protection level line-shield / shield-PG for In C2 (UP)

≤ 35 V / ≤ 650 V

Voltage protection level line-shield / shield-PG at 1 kV/µs C3 (UP)

≤ 13 V / ≤ 600 V

Test standards IEC 61643-21 / EN 61643-21

Products and technical dataDEHNpatch

TypeDPA M CAT6

RJ45S 48DPA M CLE RJ45B 48

Part No. 929 100 929 121

SPD class T

Nominal voltage (UN) 48 V

Max. cont. operating voltage (d.c. /a.c.) (Uc) 48 V / 34 V

Max. continuous operating voltage (d.c.) pair-pair (PoE) (Uc)

57 V

D1 Lightning impulse current (10/350 µs) per line (Iimp)

1 kA 0,5 kA

C2 Nominal discharge current (8/20 µs) line-line / line-PG / line-PG (total) (In)

150 A / 2.5 kA / 10 kA

C2 Nominal discharge current (8/20 µs) pair-pair (PoE) (In)

150 A

Test standards IEC 61643-21 / EN 61643-21

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White Paper Surge protection for CCTV systems

Products and technical data

BLITZDUCTOR XT / SP

Type BXT ML2 BD HFS 5 BSP ML2 BD HF 5Part No. 920 271 926 271SPD class M Q Nominal voltage (UN) 5 VMax. cont. operating voltage (d.c. / a.c.) (UC) 6.0 V / 4.2 VD1 Lightning impulse current (10/350 µs) per line (Iimp)

2.5 kA

C2 Nominal discharge current (8/20 µs) total / per line (In)

20 kA / 10 kA

Voltage protection level line-line / line-PG for In C2 (Up)

≤ 35 V / ≤ 600 V

Voltage protection level line-line / line-PG at 1 kV/µs C3 (Up)

≤ 11 V / ≤ 550 V

Cut-off frequency line-line (fG) 100.0 MHzType BXT BASPart No. 920 300For mounting on 35 mm DIN rails acc. to EN 60715Cross-sectional area (stranded / flexible) 0.08 − 4 mm2 / 0.08 − 2.5 mm2

Earthing via 35 mm DIN rails acc. to EN 60715

DEHNguard

Type DG M TN 275 DG M TT 2P 275Part No. 952 200 952 110SPD acc. to EN 61643-11/ IEC 61643-11 Type 2 / Class IIMax. continuous operating voltage (a.c.) (UC) 275 VNominal discharge current (8/20 µs) (In) 20 kAVoltage protection level (UP); [L-N] / [N-PE] (UP) ≤ 1.5 kV ≤ 1.5 kV / ≤ 1.5 kVVoltage protection level at 5 kA (UP) ≤ 1 kV

DEHNshield

Type DSH TN 255 DSH TT 255Part No. 941 200 941 110SPD acc. to EN 61643-11 / IEC 61643-11 Type 1 / Class IEnergy coordination with terminal equip-ment / with terminal equipment (≤ 5 m)

Type 1 + Type 2 / Type 1 + Type 2 + Type 3

Nominal voltage (a.c.) (UN) 230 VMax. continuous operating voltage (a.c.) (UC) 255 VLightning impulse current (10/350 µs) [L+N-PE] (Itotal)

25 kA

Lightning impulse current (10/350 µs) [L, N-PE] (Iimp); [L-N] / [N-PE] (Iimp)

12.5 kA 12.5kA / 25 kA

Nominal discharge current (8/20 µs) (In) 12.5 kA / 25 kAVoltage protection level [L-PE] / [N-PE] (UP) ≤ 1.5 / ≤ 1.5 kV

WP007/E/0814 © Copyright 2014 DEHN + SÖHNE

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Surge Protection DEHN + SÖHNE Hans-Dehn-Str. 1 Tel. +49 9181 906-0Lightning Protection GmbH + Co.KG. Postfach 1640 Fax +49 9181 906-1100Safety Equipment 92306 Neumarkt info@dehn.deDEHN protects. Germany www.dehn-international.com

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