Upload
lytruc
View
229
Download
0
Embed Size (px)
Citation preview
Connection and Protection for Comm/Data
and CCTV Networks
Eric SadlerPorta Systems Corporation
This training will discuss:
• When and why Comm/Data protection is required
• The magical devices that provide that protection
• The features and benefits of each of these devices
• The use of protection for data applications
• The use of protectors, baluns, and protected baluns for CCTV networks over unshielded twisted pair (UTP)
Primary Protectionis the LAW!
Primary Protection
• Required by the National Electric Code (NEC) Article 800.90 sec (A), enforced by building inspectors
• Defined and Qualified by UL 497 and others
Primary Protection
Installed within 50 feet of the cable entrance to any building fed by:
– Any aerial run of communications cable
– Any cable buried for more than 140 feet
When you runoutside plant cable,
you needPrimary Protection!
Protection at the Campus Environment
CENTRAL
OFFICE Telco Demarc
Hospital
Labs
School
Dorms
P
Annexes
P
P
P
P
Main Switch
P
P= Surge Protection
P
P
P
P
P
P
The NEC requires Primary Protection to ensure that the
health and safety of equipment operators
is protected.
Protected from what?
There are 865,000 Lightning Strikes each day worldwide!
Lightning is the most common source of electrical disturbance to Telecom lines
A Power Cross is the transfer of excessive voltage and current by physical contact of an electrical power line with a communications
network
The second most common source of electrical disturbance is the
Power Cross
Typical Connected Building
Power Cross withTelephone Line
But it is often overlooked!
Primary Protection is a legal requirement and also makes
good business sense
• Inspectors seldom check the installation of Comm/Data equipment for NEC compliance.
• Contractors who submit their bid with protection are more expensive than those that submit a bid without it.
• The problem with this, is that protection is very inexpensive when compared to Telecom equipment.
Whatever the property owner saves in up front costs by
not including protection, he will lose when his
equipment gets damaged!
Primary protection must contain:Surge arrestor modules in an entrance terminal
which contains 26 AWG “fusible links”
26 AWG “Fusible Link”
Surge Arrestor Module
24 AWG
PBX
22 AWG
• Gas Tube (3B1E)• Solid State (3B1S)• Hybrid• Any of these can contain overcurrent
protection as well (4B1E, 4B1S)
Common Types of Primary Protector Modules
Gas Tube Modules
Gas Tube
High energy Gas Discharge Tube dissipates surges as high as 10,000A
to ground.
Ceramic Insulator
Ceramic Insulator
3-Electrode Gas Tube Arrestor
Tip
Ring
Metal Electrode
Metal Electrode
Metal Electrode
Simultaneous short of both lines to ground
Proprietary Gas Mixture
Gas Tube Protectors• UL 497 Listed Primary Protection• Most economical• Protects
– the safety of equipment operators– prevents fires in the building– prevents damage to equipment from the
majority of surges• Self-resetting; withstands 10,000 Amps for 10
microseconds
Solid State Modules
Solid State
Solid State Components
Thyristor shorts fast-rising-voltage surges to ground, or Diode that clamps these voltages until Gas Tube shorts them to ground.
Metal Electrode
Metal Electrode
Active Silicon Wafer
Surge goes to Gnd
Equipmentis protected
Conventional Solid State Transient Voltage Suppressor (TVS)
Solid State Protectors
• Signal quality and activation energy do not deteriorate
• Provide superior protection for sensitive equipment
• Fast reaction time of less than 5 nanoseconds
• Self-resetting; withstands 100 Amps for 10 microseconds
Protector Modules are Voltage-Sensitive Devices
• You should always choose a protector module with a breakdown voltage as close to, but higher than the operating voltage of your equipment.
• This typically means 230-240 volts for analog telephone lines.
• 75-volt modules for digital telephones that do not have analog ringing voltage
• Low voltage (7.5-65 volts) for data applications we will discuss later
• Protection from surges that do not have enough voltage to trip the over-voltage devices, but still have enough energy to damage equipment!
• Modules that have in their generic part number a “4” such as 4B1E or 4B1S
• To provide this type of protection, there are a variety of devices available.
Overcurrent Protection
• Fuse
• Positive Temperature Coefficient resistor
(PTC)
• Heat Coil
Overcurrent Protection
Conventional fuseNewer
miniature fuse
Needleeye
Fuses
Fuses
• Detect low levels of current
• Require replacement after activation
• Permanently open the circuit when excess current is detected (when the fuse has blown)
Positive Temperature Coefficient Resistors (PTC)
Polymer Based
Ceramic Based
PTC’s
• Basically, a self resetting fuse• Hysteresis problems• Close the circuit when reset, but
still have the open circuit at the most critical time: during the electrical disturbance!
Heat Coil
For Overcurrent Protection
Heats up if current is too high, then spring pushes contact forward,
grounding the circuit.
Heat Coil
Thimble
Cap & Dart
Heat CoilResistance wire is coiled around
thimble
Compressed spring urging cap forward
Low-melt temperature Solder Alloy
Heat Coil
Solder melts and spring pushes dart forward
When excess current flows, the resistance wire heats up
Dart contacts ground electrode and circuit is
permanently shorted to GND
Heat Coils
• Detect low levels of current
• Permanently short the line side to ground
• Require replacement after activation
Why such acomplicated device?
• Excellent slow-blo characteristics
• Unlike PTCs and Fuses, Heat Coils ground the line instead of opening the circuit– this reduces the potential for currents to jump
to other wires
• Provides the best over-current protection for equipment fed with multi-pair cables
Reaction Time: <5 Nanoseconds
The Hybrid Protector ModulePutting the components together for the best results!
GAS TUBE
High energy discharge tube. Withstands surges as high as 10,000A dissipated to ground.
TEST POINTS
Contacts for easy circuit access/test.
CLAMPING SURGE DIODE
Clamps fast rising voltage surges until Gas Tube ionizes to short the surge to ground.
INSIDE PROTECTED PIN
HEAT COIL for Overcurrent Protection
Heats up if current is too high, then spring pushes contact forward grounding the circuit.
GROUND PIN
OUTSIDE UNPROTECTED PIN
Primary Protection Modules fulfill one part of the requirement for Primary Protection:
• Voltage Surge Suppression
To complete the requirement, one must have the second component:
• A housing with a fusible link
– A piece of thin wire located in the housing (BET) before the protector module field
– Designed to open before any other wiring in the system
Without a fusible link, any wire in a communications system could burn open during a surge and cause a fire!
A fusible link is:
Building Entrance Terminals (BETs) and Protector Packs must meet or exceed these
requirements
• Local distribution of cable in multi-tenant office buildings, high-rise apartments and campus environments
• Splice Chamber physically protects and isolates incoming gel-filled cable
• UL Listed for Primary and Secondary Protection
• Available in 25, 50 and 100 Pair• Vertically Stackable • Available in a variety of terminations• Optional cover over the protector
field
“Splice Chambered” BET
• Local distribution of cable in multi-tenant office buildings, high-rise apartments and campus environments
• Used when physical protection and isolation of incoming cable is not required
• UL Listed for Primary and Secondary Protection
• Available in 25, 50 and 100 Pair
• Available in 66 and 110 terminations and cable-stub inputs
• Economically priced
“No Splice Chamber” BET
Typical BET Installation
• Primarily used to run from a Demarc or splice casing to a separate cross connect field.
• Comes with 26 awg input Riser Rated Cable to provide fusible link
• UL Listed for Primary and Secondary Protection
• Available in 25, 50 and 100 Pair
“Stub in Stub out” BET
• Small, light-weight BET for the termination and protection of incoming copper communication cables
• Protects electronic telephone systems, particularly PBXs and KSUs
• UL Listed for Primary and Secondary Protection
• Units may be cascaded for future growth
• Available in 6, 12, and 25 pair counts
• Choice of 66 or 110 terminations
• Can be used with any of the Protector Modules we discussed
Protector Packs with Primary Protectors:
Protector Pack
(12 Pair)
Protector Pack
(6 Pair)
• Rack-Mountable 300-pair BET, fits on standard 23” x 6” deep relay rack
• Standard configuration is cable-stub input, 110, 66 or cable-stub output
• All mounting hardware and wire management guides are included
• UL Listed for Primary Protection
• Highly customizable– 1800-pair on a 7-ft. rack for protection
and cross connection– 2400-pair on a 7-ft. rack for protection
only
• Contact the manufacturer to customize an XLBET to your specifications
“XLBET”
The Primary Protection requirement applies to data systems the same
way it does for telephone systems!
• Portable Classrooms• Trailers at construction sites• Equipment controlled remotely
using Industrial Ethernet
Outside Plant Category cable can carry data to:
How does one provide Primary Entrance
Protection to devices requiring CAT 5E
performance?
CAT5E Protector Blocksand Modules
• Hubs / Concentrators, Routers• Audio / Video Equipment• Alarm Systems• Control equipment such as PLCs• IP anything!
– Computers– Phones– Cameras
CAT5E rated Blocks and Modules are used to Protect Data Network and
other Low-Voltage Equipment, Including:
• Protectors and Terminations provided in multiples of 4
• 32-pair on an 89 D mounting bracket
• Comes with DIN-rail mounting hardware for industrial applications
• Accepts CAT5E rated modules available in 7.5, 18, 27 and 65-volt models, similar in design to telephone modules.
• UL Listed for Data/Alarm and Primary Protection
CAT5E Rated Blocks Features:
How does one provide Primary Entrance
Protection to devices requiring CAT6 performance?
CAT6 Rated Protector Blocksand Modules
Building Entrance protection that maintains the full functionality of CAT 6
With ultra-low capacitance, they provide protection that permits signals of frequencies up to 250 MHz
Standard 110 style terminations for inputs and outputs
CAT6 rated modules available in 18V, 27V or 65V
Provides an ideal solution for Power Over Ethernet (POE) when used with 65-volt modules
CAT6 Rated Protector BlocksFeatures and Benefits:
CAT5E and CAT6 modules are for low-voltage data applications only!
If someone is putting telephone signal on CAT5E or
CAT6 cable, they must use one of the telephone protector modules discussed earlier!
Important!
Broadband is distinct from other data applications!
Also Important!
Broadband signals such as T1, E1, xDSL and VDSL require protectors specific for those applications
Signal voltage can vary from 205 to 400 volts
Most xDSL are best protected by modules with silicon based semiconductors specially designed to have low capacitance (~20 pF)
T1, E1, and VDSL are best protected by a hybrid gas tube/ Metallic Oxide Varistor (MOV), a metallic based semiconductor that reacts nearly as quickly as silicon based semiconductors, but have ultra-low capacitance (~5 pF)
• Coaxial Cable
• Unshielded Twisted Pair (UTP)
Protection plays a role in CCTV applications that run
over copper wires
For Installations that use Coaxial Cable, there are coaxial
Protectors available (BNC to BNC)
Coaxial Protector
• Installed in front of cameras and/or recording devices• Standing wave ratio – 1.2:1• Low Pass – 20 Hz - 40 MHz• Insertion Loss - <0.3dB @ 40 MHz• Durable Design
Coaxial Protector
UTP is less expensive than Coaxial Cable UTP is less bulky and easier to install UTP can run for longer distances, 1000-2000 feet easily
compared to 600 feet for Coax Many times structured cabling is already in place and one
can use the existing UTP to run the CCTV network Allows easy upgrade to IP cameras on UTP of CAT5E or
better.
The Modern trend is to run CCTV networks over UTP. Why?
For UTP Installations, there are protectors specifically for the
application of cameras over UTP
UTP Protectors
• Single and double Channel Multi-function protector• Supports camera control signals RS422 and RS485 over UTP, as well
as camera signal and power • Compact Design
UTP Protectors
Video Baluns
• The devices that permit the transmission of video signals over UTP• Mini versions fit inside camera housings• Amplified versions or “Active Baluns” permit transmission over
greater distances• Models available both with and without surge protection
Video Baluns Active Video Balun
Video Combiners
• Provide for the combination of video signal, power and control for PTZ cameras over UTP
• Connectorized (RJ45) or with 110 terminations• Passive device – no power required• Can pass power through them to power the camera
Video Combiners
Video Combiners with Protection
• Provide the combination of video, power and control for PTZ cameras over UTP or a combination of UTP and coaxial cable
• Provides protection form surges• Passive device – no power required• Can pass power through them to power the camera
Combiners with Protection