1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULJanuary 25, 20111SUBJECT 497EOUTLINE OF INVESTIGATIONFORPROTECTORS FOR ANTENNA LEAD-IN CONDUCTORSIssue No. 4January 25, 2011Summary of TopicsThis is the Fourth issue of the Outline of Investigati
2、on for Protectors forAntenna Lead-In Conductors, Subject 497E, which covers devices that areused to limit surges on the cable that connects the antenna to thereceiver/transmitter electronics and are connected between theconductors and the grounded shield or other ground connection.COPYRIGHT 2011 UND
3、ERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULJANUARY 25, 2011SUBJECT 497E2No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTROD
4、UCTION1 Scope .52 Components .63 Units of Measurement 64 Undated References 75 Glossary .7CONSTRUCTION6 General 87 Enclosures .87.1 General .87.2 Sheet metal 97.3 Nonmetallic 98 Protection Against Corrosion .99 Wiring Connections .99.1 Coaxial connections 99.2 Grounding .910 Components .1010.1 Gener
5、al .1010.2 Arrester assemblies 1110.3 Electrical insulation material .1110.4 Polymeric materials .11PERFORMANCE11 General 1112 Performance Verification Tests .1412.1 General .1412.2 Impulse sparkover voltage measurement test (not applicable to dc shorting typeprotectors) .1512.3 Insulation resistanc
6、e test (not applicable to dc shorting type protectors) .1612.4 Breakdown voltage measurement test (not applicable to dc shorting type protectors) .1612.5 Residual voltage measurement test (dc shorting type protectors) .1712.6 Combination devices 1813 Maximum Discharge Current (Imax) Test .1814 Nomin
7、al Discharge Current (In) Test (Optional) .1915 Discharge Test .2016 Conditioning Tests 2216.1 Impulse endurance conditioning test 2216.2 Drop test 2216.3 Thermal cycling test 2216.4 Humidity conditioning test .2316.5 Indoor corrosion tests .2316.6 Outdoor corrosion tests .2317 Capacitor Thermal Agi
8、ng Test 2418 Component Temperature Test 2519 Dielectric Voltage-Withstand Test 2620 Distortion Test .26JANUARY 25, 2011 SUBJECT 497E 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL21 Impact Test (Polymeric Enclosures) .2622 Water Spray Test
9、(Outdoor Units Only) 2623 Ultraviolet Light and Water Exposure (Outdoor Units Only) 2724 Tensile Strength and Elongation Tests 2725 Air Oven Aging Test 2726 Ozone Exposure Test 27MARKINGS27 General 27INSTALLATION INSTRUCTIONS28 General 28JANUARY 25, 2011SUBJECT 497E4UL COPYRIGHTED MATERIAL NOT AUTHO
10、RIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 This Outline of Investigation covers protectors for antenna lead-in conductors. These devices areused to limit surges on the cable that connects the antenna to the receiver/transmitter electronics and arec
11、onnected between the conductors and the grounded shield or other ground connection. Typicalapplications include antenna installations for radio and television receiving equipment, amateur radiotransmitting and receiving equipment, cellular telephone towers and WiMax or WiFi wireless networks.1.2 As
12、covered by these requirements, protectors for antenna lead-in conductors typically consists of airgap arresters, gas tube arresters, solid-state arresters or quarter-wave stub type devices, or combinationsof these devices. Other technologies are not excluded. They may or may not contain additionalco
13、mponents such as inductors or blocking capacitors. These protectors are intended to protectequipment, wiring, and personnel at the premises against the effects of excessive potentials and currentson the conductors caused by lightning.1.3 These devices operate to divert a surge current to earth, and
14、control the residual voltage (also knownas let-through voltage) to a suitable level. Once the surge current has subsided, the device automaticallyreturns normal operation and reset to a state ready to receive the next surge. Residual voltage limits ortheir suitability to minimize damage to connected
15、 equipment is not within the scope of these requirements.1.4 These protectors are investigated for their maximum discharge current (Imax) capability using an 8/20current waveform. This is the maximum impulse current the protector can withstand, including afterenvironmental conditioning, without affe
16、cting its surge limiting capability or creating a risk of fire,fragmentation or electrical shock.1.5 This Outline does not cover the following:a) Lightning protective devices for the protection of secondary distribution wiring systems andequipment.b) Antenna discharge units for radio and television
17、receiving appliances that are covered by theStandard for Antenna-Discharge Units, UL 452.c) Lightning conductor and air terminals for connection of lightning rods for building protection.d) Protectors for fire alarm signaling circuits that are covered by the Standard for Protectors forData Communica
18、tions and Fire-Alarm Circuits, UL 497B.e) Equipment covered by the Standard for Secondary Protectors for Communications Circuits,UL 497A.f) Equipment covered by the Standard for Surge Protective Devices, UL 1449.g) Equipment covered by the Standard for Protectors for Paired-Conductor CommunicationsC
19、ircuits, UL 497.h) Equipment covered by the Standard for Protectors for Coaxial Communications Circuits, UL497C.i) DC blocking connectors or components that do not have lightning protection as their primaryfunction.JANUARY 25, 2011 SUBJECT 497E 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REP
20、RODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULj) Applications where follow-on currents may occur, such as installations where communicationswiring is routed on shared facilities with electrical distribution systems.1.6 Special installation methods are required for equipment connected to wire-li
21、ne communicationfacilities serving high-voltage electric power stations operating at greater than 1 kV. These requirementsdo not cover the equipment or devices used in the design of such installations. Special system designrequirements, such as those covered by Recommended Practice for the Protectio
22、n of Wire-LineCommunication Facilities Serving Electric Power Locations, IEEE 487, shall be followed to reduce therisks associated with wire-line communication facilities serving such power stations.2 Components2.1 Except as indicated in 2.2, a component of a product covered by this Outline shall co
23、mply with therequirements for that component.2.2 A component is not required to comply with a specific requirement that:a) Involves a feature or characteristic not required in the application of the component in theproduct covered by this outline orb) Is superseded by a requirement in this outline.2
24、.3 A component shall be used in accordance with its rating established for the intended conditions ofuse.2.4 Specific components are incomplete in construction features or restricted in performance capabilities.Such components are intended for use only under limited conditions, such as certain tempe
25、ratures notexceeding specified limits, and shall be used only under those specific conditions.3 Units of Measurement3.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.3.2 Unless otherwise indicated, all voltage and current value
26、s specified in this outline areroot-mean-square (rms).JANUARY 25, 2011SUBJECT 497E6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL4 Undated References4.1 Any undated reference to a code or standard appearing in the requirements of this outlin
27、e shall beinterpreted as referring to the latest edition of that code or standard.5 Glossary5.1 For the purpose of this outline the following definitions apply.5.2 COMBINATION WAVEFORM GENERATOR A surge generator with a 2-ohm internal impedanceproducing a 1.2/50 s open circuit voltage and an 8/20 sh
28、ort-circuit current waveshape.5.3 DIRECT CURRENT (DC) BREAKDOWN VOLTAGE The voltage at which an arrester changesfrom non-conduction to conduction when the DC potential is increased at a rate not greater than 2000Volts per second.5.4 INDOOR USE (CONTROLLED ENVIRONMENT) Installation of equipment in an
29、 area where theatmosphere is artificially controlled. For the purpose of this Outline, indoor ambient is limited to atemperature of 0 30C. Limits for corrosion concentrations are defined in the test program. Rain doesnot occur.5.5 LIGHTNING IMPULSE CURRENT (Iimp) See Maximum Discharge Current, 5.6.5
30、.6 MAXIMUM DISCHARGE CURRENT (Imax) The maximum instantaneous value of the currentthrough the protector having an 8/20 waveshape. From the Standard for the Installation of LightingProtection Systems, NFPA 780. Other common terms for “maximum discharge current” include but arenot limited to:a) Lightn
31、ing current carrying capability;b) Lightning impulse current (Iimp) see Lightning Protection Components (LPC) Part 3:Requirements for isolating spark gaps, EN 50164-3;c) Impulse discharge current;d) Withstand current;e) Surge discharge current;f) Surge current capability;g) Discharge current;h) Maxi
32、mum impulse discharge;i) Surge current;j) Peak pulse current; andk) Maximum transient.JANUARY 25, 2011 SUBJECT 497E 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL5.7 NOMINAL DISCHARGE CURRENT (In) Peak value of 8/20 s current waveform selec
33、ted by themanufacturer for which a protector remains functional after 15 surges. From the Standard for theInstallation of Lighting Protection Systems, NFPA 780.5.8 OUTDOOR USE (UNCONTROLLED ENVIRONMENT) An area subjected to the naturalenvironmental conditions which make-up the ambient and moisture e
34、xtremes of this plant. For thepurpose of consistency, the ambient and moisture extremes are defined in the various tests of thisOutline.5.9 PROTECTOR A device intended to prevent damage to a circuit or system when abnormally highvoltages occur.CONSTRUCTION6 General6.1 A protector for antenna lead-in
35、 conductors shall be constructed to withstand, without damage, itsintended installation and use and shall comply with the applicable performance requirements specified inSections 11 27.6.2 A protector shall not have provision for adjustment of its surge limiting components. For dc shortingtype prote
36、ctors, it is permissible for the operating pass-through frequency to be adjustable as long as itremains beyond normal lightning frequencies, typically above 10 MHz.6.3 An uninsulated live part shall be secured to an insulated mounting surface so that it is prevented fromturning or shifting in positi
37、on, when such motion is capable of resulting in a reduction of spacings.6.4 A protector assembly shall be protected against fouling by dust or other material capable of affectingintended operation.6.5 A current-carrying part shall be silver, copper, copper-alloy, or any non-corrosive metal that comp
38、lieswith the test current requirements of this Outline.7 Enclosures7.1 General7.1.1 An enclosure shall have the strength and rigidity to resist total or partial collapse with attendantreduction of spacings, loosening or displacement of parts, or other conditions that impair the operation ofthe devic
39、e and increase the risk of fire, electric shock, or injury to persons.7.1.2 Enclosures for individual components, outer enclosures, and combinations of the two areconsidered in determining compliance with 7.1.1.7.1.3 Protector enclosures shall have provision for mounting. For installations utilizing
40、 hard-line coaxialcable, it is acceptable to use the cable connections as the mounting means.JANUARY 25, 2011SUBJECT 497E8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL7.1.4 A protector intended for outdoor use shall be provided with a water
41、-resistant cover or enclosure thatis resistant to corrosion and the effects of UV radiation.7.2 Sheet metal7.2.1 See Sheet metal, Section 5.2 of the Standard for Protectors for Coaxial Communications Circuits,UL 497C.7.3 Nonmetallic7.3.1 An enclosure of nonmetallic material for a protector shall hav
42、e the mechanical strength anddurability intended for the application and be formed so that it covers all uninsulated non-groundedcurrent-carrying parts. Nonmetallic enclosures shall employ material rated 5VA or shall comply with the127 mm (5 inch) flame test of the Standard for Polymeric Material Us
43、e in Electrical EquipmentEvaluations, UL 746C.8 Protection Against Corrosion8.1 See Protection Against Corrosion General, Section 6.1 of the Standard for Protectors for CoaxialCommunications Circuits, UL 497C.9 Wiring Connections9.1 Coaxial connections9.1.1 A coaxial type protector shall be provided
44、 with a threaded receptacle which accepts the matingconnector of a coaxial cable to which it is intended to be connected.9.2 Grounding9.2.1 A protector shall be provided with a method of grounding consisting of at least one of the following:a) A field wiring terminal;b) An attached grounding lead or
45、 strap of a minimum of 12 AWG (3.3 mm2) copper, orequivalent;c) A tab with a through hole, a tapped hole, or a threaded stud for mounting the protector to agrounded metal panel; ord) A threaded bulkhead with mounting hardware, for fastening the protector through a hole in agrounded panel.9.2.2 The s
46、hield of a coaxial cable shall not be used as the main grounding connections for the protector.9.2.3 A protector field wiring terminal shall have provision for connecting at least one grounding conductornot smaller than 12 AWG (3.3 mm2). A three- to six-cable protector shall have provision for conne
47、cting atleast one grounding conductor not smaller than 10 AWG (5.3 mm2). Protectors intended for connectingmore than six circuits shall have provision for connecting at least one grounding conductor not smallerthan 6 AWG (13.3 mm2). All protector ground terminals shall be capable of connecting a min
48、imum 14AWG (2.1 mm2) wire.JANUARY 25, 2011 SUBJECT 497E 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL9.2.4 The following terminal configurations are suitable for the connection of field wiring:a) A stud-type terminal post with securing loc
49、kwasher and nut the post shall not be smallerthan No. 6-32 (3.5 mm) screw size.b) A compression contact where the grounding wire is inserted into a retaining hole of theprotector and secured with a (set)screw, provided that the screw end form will not cut or shearthe conductor during installation.c) A wire binding head screw, provided that the strew size is not smaller than No. 6 (M3.5)screw size. The metal terminal plate shall be extruded at the tapped hole so as to engage thescrew for a length of at least 2 full threads.9.2.5 A grounding terminal sh
