1、August 1, 20021SUBJECT 2389OUTLINE OF INVESTIGATIONFORCOAXIAL FAULT PROTECTORS FOR NETWORK-POWERED BROADBANDCOMMUNICATIONS SYSTEMSIssue Number: 1AUGUST 1, 2002COPYRIGHT 2002 UNDERWRITERS LABORATORIES INC.AUGUST 1, 2002SUBJECT 23892No Text on This PageCONTENTSFOREWORD 4INTRODUCTION1 Scope .52 General
2、 52.1 Units of measurement .52.2 Undated references .5CONSTRUCTION3 General 6PERFORMANCE4 General 65 Samples .76 Test Sequence for Assigned Samples .77 Normal Operation Test 98 Component Temperature Test .109 Limited Short-Circuit Test .119.1 Method .119.2 Results .1210 Endurance Conditioning Test .
3、1210.1 Method .1210.2 Results .1311 Induced Low-Current Test .1312 Variable Ambient Test .1413 Water Spray Test .1414 Dielectric Voltage-Withstand Test .1715 Abnormal Operation Test 1716 Endurance Cycling Test .1817 Jarring Test 18AUGUST 1, 2002 SUBJECT 2389 3FOREWORDA. This Outline of Investigation
4、 contains basic requirements for products covered by UnderwritersLaboratories Inc. (UL) under its Follow-Up Service for this category within the limitations given below andin the Scope section of this Outline of Investigation. They are subject to revision as further experience andinvestigation may s
5、how is necessary or desirable.B. The observance of these requirements by a manufacturer is one of the conditions of the continuedcoverage of the manufacturers product.C. A product which complies with the text of this Outline of Investigation will not necessarily be judged tocomply with the Outline o
6、f Investigation if, when examined and tested, it is found to have other featureswhich impair the level of safety contemplated by these requirements.D. A product that contains features, characteristics, components, materials, or systems new or differentfrom those covered by the requirements in this O
7、utline of Investigation, and that involves a risk of fire orof electric shock or injury to persons shall be evaluated using appropriate additional component andend-product requirements to maintain the level of safety as originally anticipated by the intent of thisOutline of Investigation. A product
8、whose features, characteristics, components, materials, or systemsconflict with specific requirements or provisions of this Outline of Investigation does not comply with thisOutline of Investigation. Revision of requirements shall be proposed and adopted in conformance with themethods employed for d
9、evelopment, revision, and implementation of this Outline of Investigation.E. UL, in performing its functions in accordance with its objectives, does not assume or undertake todischarge any responsibility of the manufacturer or any other party. The opinions and findings of ULrepresent its professiona
10、l judgement given with due consideration to the necessary limitations of practicaloperation and state of the art at the time the Outline of Investigation is processed. UL shall not beresponsible to anyone for the use of or reliance upon this Outline of Investigation by anyone. UL shall notincur any
11、obligation or liability for damages, including consequential damages, arising out of or inconnection with the use, interpretation of, or reliance upon this Outline of Investigation.F. Many tests required by the Outline of Investigations of UL are inherently hazardous and adequatesafeguards for perso
12、nnel and property shall be employed in conducting such tests.AUGUST 1, 2002SUBJECT 23894INTRODUCTION1 Scope1.1 This Outline of Investigation contains construction and test requirements for coaxial fault protectorsthat connect into the underground distribution or feeder cable to a residential unit or
13、 property. Theseproducts are intended for use only with network-powered broadband communication systems employingunderground cable to the premise. These systems permit low power on the center conductor of the coaxialcable. The power limits are in accordance with Article 830 of the National Electrica
14、l Code, NFPA 70.1.2 These requirements are intended for broadband communications circuits employed in the outsideplant which operate in a similar manner to plain old telephone (POT lines) circuits and which encounterthe same environmental problems and are installed in a similar manner to telephone c
15、ircuits.1.3 These requirements are intended for products which connect in series with the coaxial line and obtainoperating power from that circuit. The coaxial fault protector monitors the coaxial circuit for openconditions in the center conductor and for shorts or leakage current to ground from the
16、 center conductor.Leakage current may occur between the coaxial cable center conductor and its shield. The shield shall bebonded to system ground which may also be considered earth ground. The cable shall be typically burieddirectly in the soil (without conduit) less than 18 inches below finished gr
17、ade. This type of installationexposes the cable to environmental problems, mechanical abuse, and tampering. In the event a faultoccurs, the coaxial fault protector shall disconnect the systems operating power to the premises. Normaloperation is the functional process of the product to detect a fault
18、 and disconnect power.2 General2.1 Units of measurement2.1.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.2.2 Undated references2.2.1 Any undated reference to a code or standard appearing in the requirements of the outline sha
19、ll beinterpreted as referring to the latest edition of that code or standard.AUGUST 1, 2002 SUBJECT 2389 5CONSTRUCTION3 General3.1 Products covered by this Outline are in compliance with the construction requirements in the Standardfor Protectors for Coaxial Communications Circuits, UL 497C.3.2 This
20、 type of protection system involves the use of two electronic modules operating as a completesystem; these modules are referred to as the tap-end and premise-end. Each module is located ateach end of the protected cable and communicate with each other to provide the intended protectioncapability of
21、the system. This type of system physically limits the length of protected cable. The followingtest program and other specified requirements are applicable to other technologies designed to providethe same protection for broadband communications underground cable.3.3 In the event of a fault condition
22、, the AC power on the subscriber feeder cable located on theresidential property is to be disconnected. To accomplish this, power is to be disconnected at the serviceproviders end (tap-end) of the circuit. The service provider controls placement of the tap-end module. Thisend is typically installed
23、in a pedestal enclosure, mounted on a utility pole, or some other similartermination point inaccessible to the general public and controlled by the service provider. The subscribermodule is located at the building entrance point, thus establishing the other end of the protected cable.This module wou
24、ld be installed in a network interface box listed in one of the network interface categoriesfor telephone or multimedia communication equipment.3.4 Article 830 in the National Electrical Code, ANSI/NFPA 70, requires mechanical protection for thecable where it leaves the soil, rises, and terminates t
25、o the protection modules. To accomplish this, themanufacturers installation practice shall specify the use of conduit or other acceptable outdoor raceways.The conduit is to be used at both ends of the cable as it rises above finish grade and terminates withinan acceptable enclosure.PERFORMANCE4 Gene
26、ral4.1 Three aspects of normal operation are addressed in this test program:a) Determine the minimum leakage current level at which the product will detect and begin itsoperation to disconnect power at a variety of leakage current levels.b) Monitor and record how fast the product will react and disc
27、onnect.c) Determine the products ability to detect an open circuit or short-circuit condition in the low-power broadband cable and disconnect power.4.2 A leakage current detection level of between 0.5 5.0 milliamperes is considered appropriate for thistype of product. The minimum value prevents prem
28、ature tripping and relates to a startle reaction effecton people while the higher value is considered the maximum limit that prevents electric shock. Based onthe operating time limit formula for GFCIs, the coaxial fault protector under investigation is required todisconnect power in less than 7.2 se
29、conds from point of fault detection when the leakage current level of5.0 milliamperes is reached.AUGUST 1, 2002SUBJECT 238964.3 Power disconnection is verified with a suitable meter or oscilloscope. Power is required to remaindisconnected until the fault is removed or continuity of the coaxial cable
30、 is restored to normal.4.4 In addition to reducing the risk of fire and electric shock, these test requirements are to be used totest products for their ability to detect and eliminate the fault hazard.4.5 The correct functionality of the product is dependent upon its ability to detect and eliminate
31、 faults,resistivity to outdoor environmental concerns, and proper placement of the product that enables it toprevent a risk of electric shock when a fault occurs.5 Samples5.1 Representative samples of the coaxial fault protector constructed as production-line units are to besubmitted by the manufact
32、urer and subjected to the following test program.5.2 A test program is required in order to evaluate the coaxial fault protectors ability to monitor and detectan open- or short-circuit condition in the coaxial center conductor of the drop cable. The test program isalso used to evaluate the detectors
33、 ability to detect a leakage-current condition that may exist betweenthe coaxial center conductor and the coaxial shield of the drop cable.6 Test Sequence for Assigned Samples6.1 The flow chart in Figure 6.1 illustrates the testing sequence. The assigned samples are required toperform the tests in t
34、he order specified in the flow chart.This is generated text for figtxt.AUGUST 1, 2002 SUBJECT 2389 7Figure 6.1Testing sequence flow chartAUGUST 1, 2002SUBJECT 238987 Normal Operation Test7.1 Each one of the 35 coaxial fault protector samples is to be mounted in a position of normal use andconnected
35、to a coaxial cable communication loop as specified in the manufacturers installationinstructions. The premise-end of the communication loop is to be terminated with a resistive load, whichsimulates the load of the circuit in the network interface device. The tap-end (outside plant) of thecommunicati
36、on loop is to be connected to an AC power source, which simulates a network-poweredbroadband communications system source. The power source is to be adjusted to rated voltage and theload resistance adjusted for rated maximum current.7.2 A leakage current fault is to be simulated on the coaxial cable
37、 by placing a variable resistancebetween the center pin conductor of the coaxial cable and its shield. Placing a removable jumper wirebetween a severed center pin conductor simulates an open-circuit condition in the center pin conductor.Placing a removable jumper wire between the center pin conducto
38、r and the coaxial cable shield simulatesa short-circuit condition. Each fault condition is to be placed between the premise-end module and thetap-end module, applied separately. With the simulated faults ready for activation, the system is to beenergized and the results noted.7.3 Tested samples shal
39、l comply with the following:a) The AC power shall be interrupted on the coaxial cable within 7.2 seconds when an open-circuit condition is created on the center pin conductor.b) The AC power shall be interrupted within 7.2 seconds when a leakage current condition of5.0 mA is detected between the cen
40、ter pin conductor and cable shield. The AC power shall beinterrupted within 195.4 seconds when a leakage current condition of 0.5 mA is detectedbetween the center pin conductor and cable shield.c) The AC power shall not be interrupted on the cable when a leakage current condition (asspecified by the
41、 manufacturer) exists between the center pin conductor and cable shield.7.4 The AC power shall disconnect when the protection system is subjected to separate open-circuit,short-circuit, and leakage-current conditions. Tests for each condition is to be conducted at both voltagelimits of the rated ran
42、ge. The disconnection time for each of these conditions shall not exceed the limitsspecified in Table 7.1.AUGUST 1, 2002 SUBJECT 2389 9Table 7.1Maximum time tableVoltage Leakage current, (mA) Maximum allowable time, secondsLow-voltage limit of rated rangeV AC 0.5 195.4V AC 1.0 72.5V AC 1.5 40.6V AC
43、2.0 26.9V AC 2.5 19.5V AC 3.0 15.1V AC 3.5 12.1V AC 4.0 10.0V AC 4.5 8.4V AC 5.0 7.2V AC 5.5 6.3V AC 6.0 5.6High-voltage limit of rated rangeV AC 0.5 195.4V AC 1.0 72.5V AC 1.5 40.6V AC 2.0 26.9V AC 2.5 19.5V AC 3.0 15.1V AC 3.5 12.1V AC 4.0 10.0V AC 4.5 8.4V AC 5.0 7.2V AC 5.5 6.3V AC 6.0 5.68 Comp
44、onent Temperature Test8.1 A sample of the coaxial fault protector is to be mounted in a position of normal use and connectedas described in the Normal Operation Test, Section 7. A rated power source is to be applied to the tap-endcircuit. Temperatures of the protector components are to be monitored
45、using an infrared thermometera.The maximum temperatures are to be recorded after 1 hour. In the event of a rated voltage range, thetest is to be repeated for both voltage limits of the rated voltage range.aSuch as the C-600E thermometer by Linear Laboratories.8.2 The components are to be monitored t
46、o determine that the surface temperature of each componentis equal to or less than the maximum allowable temperature rise per component as specified in theStandard for Protectors for Coaxial Communications Circuits, UL 497C. Room ambient is to be 23 3Cduring testing.AUGUST 1, 2002SUBJECT 2389109 Lim
47、ited Short-Circuit Test9.1 Method9.1.1 Fifteen samples of the coaxial fault protector are to be subjected to this test. Each sample is to beconnected to a cable type specified by the manufacturer and terminated as described in the NormalOperation Test, Section 7. The samples are to be divided into f
48、ive groups with three samples in eachgroup.a) The first group is to be placed in an outdoor concentration of H2S corrosion for ten days.b) The second group is to be placed in an outdoor concentration of CO2SO2corrosion forten days.c) The third group is to be placed in a salt spray (NaCl) environment
49、 for ten days.d) A fourth group is to be placed in a 95 percent humidity environment for 24 hours.e) The fifth group is to be subjected to 50 cycles of a heating at 150F and cooling at a minus30F environment with each cycle consisting of 15 minutes per environment.At the end of each conditioning period, the samples are to be allowed to dry for 24 hours before beingsubjected to the test currents. See Table 9.1 for the list of test conditions.9.1.2 The premise-end module is to be placed in a network interface device (NID), subscriber interfaceunit (SIU), or compatible encl
