Transcript Surge Protection

Bubble of Protection
Complete System Protection
ITW Linx
A Division of Illinois Tool Works Inc.
Overview
 Why Use Surge Protection?
 Types of Surges
 Technologies
 Standards
 The “Bubble of Protection”
 Bonding and Grounding
 Example
©2003
Why Use Surge Protection?
Safety
Protect people from electric shock
Protect equipment from damage
Protect building wiring from excessive electrical
current
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Why Use Surge Protection?
Safety
National Electric Code
National Fire Protection Association
Telecom equipment under Article 800
Primary Protection at Building Entrance
Secondary protection
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Why Use Surge Protection?
Safety
National Electric Code
Savings
Blown Equipment
Service Calls
Downtime
Initial Investment with Net Savings
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Why Use Surge Protection?
Safety
National Electric Code
Savings
Damaged Equipments Equals….Headaches
Lost Equipment
Service Repairs
System/Business Downtime
Dissatisfied Customers
Finger Pointing (Installer, Manufacturer, etc.)
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Why Use Surge Protection?
Safety
National Electric Code
Savings
Damaged Equipments Equals….Headaches
Who’s Concerned?
Telephone and Power Companies
Facility, Operations, and Telecom Managers
Architects, Installers, Contractors, Technicians
Everyone!
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Types of Surges
Lightning
Most catastrophic of all surges
Does not have to be a direct hit to cause damage
A lightning strike within a few miles can be induced
into aerial or buried cables
10,000,000 Volts
145,000 Amps (145kA)
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Global Lightning Flashes 2000
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Lightning in the U.S. 1989-1998
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Types of Surges
 Lightning
 Power Line Cross
 Excess current on the Communications line
 High Risk of Fire
 Injury to personnel
 Damage to equipment
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Types of Surges
 Lightning
 Power Line Crosses
 Induction
 Current flow creates a magnetic field
 Two conductors run parallel and close to one another
 Field of one conductor can transfer energy to the other
conductor
 Example: Power is first restored following a blackout
Field
Current
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Types of Surges
 Lightning
 Power Line Crosses
 Induction
 Electrostatic Discharge
 Transfer of electrical energy from one material to another
 Usually found in dry climates
 Produces high voltage with low current
 Feel sensation at 4kv
 Maximum Voltage = 30kV
 Enough energy to damage integrated circuits (~35V)
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Shock Thresholds
1mA
Perception Threshold
3mA
Mild Shock
8mA
Severe Shock (involuntary muscle movement)
10mA Freezing Threshold (can’t let go)
35mA Respiratory Paralysis
65mA Heart Filtration (no blood flow)
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Technologies
Voltage Limiting
Gas Tube
Discharge gap between two metal electrodes
Poor control of peak voltage
Clamping voltages are too high
Discharge times are too slow
Deposits build on the discharge plates with each activating surge
OK for electromagnetic switches, but not for today’s electronics
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Technologies
Voltage Limiting
Gas Tube
Solid State
Provides fast, precise, and long lasting protection
Premium alternative to gas tube protectors
Fast clamping at low voltages
Performance can significantly reduce failure rates for both
protector units and surge sensitive equipment
Improved reliability makes it ideal for critical service lines
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Speed of a Surge
How Fast Does Electricity Travel Through A Wire?
Number of Feet in a Mile?
186,000 Miles/Second
5,280 Feet / Mile
Speed (in ft/sec) Electricity Travels Through a Wire
1,000,000,000 ft/sec
Time Required for Surge to Travel One Ft.
0.0000000001 Sec.
(1 Nanosecond)
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Speed of a Surge
Device
Fuse
Response Time
Distance Surge Traveled Past
Device Before It Responded
300,000 ns
300,000 ft
5,000 - 10,000 ft
Carbon Block
5,000-10,000 ns
or 1-2 miles.
4,000 - 5,000 ft
Gas Tube
4,000-5,000 ns
Or 1 mile.
Solid-State
2 - 5 ns
2 - 5 ft
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Technologies
Voltage Limiting
Gas Tube
Solid State
Current Limiting
Sneak Current Protector Fuses
Prevents the current that passes by the primary protector
undetected from burning down building
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Technologies
Voltage Limiting
Gas Tube
Solid State
Current Limiting
Sneak Current Protector Fuses
PTC’s
Positive Temperature Coefficient (PTC)
Automatically reset once the over current is removed
Service calls/costs are dramatically reduced
Cost of replacement fuses eliminated
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Standards
National Electric Code (NEC)
National Fire Protection Agency for Safety
Article 800 - Telecommunications
All conductive paths entering or leaving a building
shall be protected by a listed primary protector as
soon as possible, but no more than 50 feet past the
building entrance
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Standards
National Electric Code (NEC)
Underwriters Laboratory (UL)
Products listed
Do not start on fire or cause a fire to be started, and
Do not cause a physical safety hazard to the use
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Standards
National Electric Code (NEC)
Underwriters Laboratory (UL)
UL497 - Primary
Designed to protect against Lightning and Power Crosses
 100 Amp, 10/1000
 600V, 350A
Three Exceptions
 Large metropolitan area
 Less than 140ft
 <5 Thunderstorm days per year
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Standards
National Electric Code (NEC)
Underwriters Laboratory (UL)
UL497 – Primary
UL497A – Secondary
Installed in series between the primary protector and the equipment
Must safely limit over currents
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Standards
National Electric Code (NEC)
Underwriters Laboratory (UL)
UL497 – Primary
UL497A – Secondary
UL497B – Isolated Loop (Fire Alarm or Data Circuit)
For lines that are contained within a building and not connected to
the public network outside the building
These devices protect against transients usually caused by
electrostatic discharge and electrical shock
NOT INTENDED FOR LIGHTNING PROTECTION
©2003
Standards
National Electric Code (NEC)
Underwriters Laboratory (UL)
UL497 - Primary
UL497A – Secondary
UL497B – Isolated Loop (Fire Alarm or Data Circuit)
UL1449 – Transient Voltage Surge Suppressor
AC Power listing at 330V
For electrical safety, NOT equipment safety
©2003
Risk Assessment
 Where is the facility (Lightning potential)?
 What is the Power Quality?
 Outside Extensions?
 What is the Ground Quality?
 How Critical is the System?
 What Will It Cost to Replace the System?
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Secondary
Primary
Primary
PBX
Secondary
Primary Protection
Telco Demarcation
CO
LINES
Secondary
Typical Install
CAMPUS BUILDING
MAIN BUILDING
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“Bubble of Protection”
Backwards Approach
Three potential conductive paths
1) AC Power
2) Communications Lines (Telecom)
3) Ground System
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Bubble of Protection
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Final Layout
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Bonding & Grounding
 Grounding: Establish 0V Reference
 Bonding: Maintaining 0V Reference
 Two Point Resistance < 0.1Ω
 Direct attachment to the closest point in the building’s
electrical service grounding electrode system is preferred
 90% of problems are due to improper grounding
 Good grounds
 Structural Steel
 Electrical Service Panel
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Bonding & Grounding
 Ground Impedance < 1Ω
 Tightness of Connections (Check Annually)
 Length (Short as Possible)
 Number of Bends (Straight as Possible)
 Bend Radius (Generous)
 Size/Gauge
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Bonding & Grounding
 Ground Impedance (Earth Gnd) < 1.0 ohms
 Single Point Ground
 Racks
 Cable Trays
 Raised Floor
 Conduits
 Structural Steel
 Equipment
 Cold Water Pipe
 AC Panel
©2003
Bonding & Grounding
 Ground Impedance (Earth Gnd) < 1.0 ohms
 Single Point Ground
 Protect or Ground Unused Pairs
©2003
Bonding & Grounding
 Ground Impedance (Earth Gnd) < 1.0 ohms
 Single Point Ground
 Protect or Ground Unused Pairs
 Use proper gauge wire (AWG)
 Receptacle ground for small systems
 TMGB for large systems
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Ground Size
Primary
Pairs
1-2
3-6
7-25
Fuseless
12
10
6
Fused
14
14
6
Secondary
 Not specified by UL or NEC
 Check Manufacturer’s Specifications
 Depends on size of system and current carry capacity
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Example – Airport Installation
The damaged phone switch
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Example – Airport Installation
A Good Single Point Ground But…
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Example – Airport Installation
In Another Room, the Ground Wire…
IT’S NOT CONNECTED TO ANYTHING!
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Don’t let this happen
to your system
©2003
Questions?
Contact ITW Linx
800-336-5493
www.itwlinx.com