Telecommunication terminal equipment electrical safety requirements
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- Class Type of equipment Maximum leakage current, mA
- A4.3. Single - phase equipment
- A4.4. Three-phase equipment
- A4.5. Equipment with earth leakage exceeding 3.5 mA
- A5. Earth leakage current for equipment intended to be connected directly to IT power systems A5.1. General
- A5.3. Single - phase equipment
- A5.4. Three - phase equipment
- A5.5. Equipment with earth leakage exceeding 3.5 mA
- Test impulse C 1 R 1 R 2
- ANNEX D
- D3.2. Tripping device and monitoring voltage
- F1. Examples of equipment which is within the scope of this standard are
- Technical requirements Compliance Reference
A4. Earth leakage current A4.1. General Equipment intended to be connected to TT or TN power systems shall comply with the requirements in A4.2 to A4.5. Equipment intended to be connected directly to IT power systems shall comply with the requirements in A5. A4.2. Requirements Equipment shall not have earth leakage current in excess of the values in table A4.1 when measured as defined A4.3 or A4.4. Table A4.1: Maximum earth leakage current
Systems of interconnected equipment with individual connections to primary power shall have each piece of equipment tested separately. Systems of interconnection equipment with one common connation to primary power shall be treated as a single piece of equipment. Equipment designed for multiple (redundant) supplies shall be tested with only one supply connected. If it is clear from a study of the circuit diagrams of class I permanently connected equipment or pluggable equipment type B that the earth leakage current will exceed 3.5 mA, but will not exceed 5% of input current, the test need not be made. If it is inconvenient to test equipment at the most unfavorable supply voltage, it is permitted to test at any available voltage within the rated voltage range or within the tolerance of rated voltage, and then calculate the results.
Single - phase equipment intended for operation between one phase conductor and neutral is tested using the circuit of figure A4.1 with the selector switch of the positions 1 and 2. For each position of the selector switch, any switches within the equipment controlling primary power and likely to be operated in normal use are opened and closed in all possible combinations. None of the current values shall exceed the relevant limit specified in table A4.1. 
Figure A4.1: Test circuit for earth leakage current on single-phase equipment A4.4. Three-phase equipment Three-phase equipment and equipment intended for operation between two phase conductors are tested using the circuit of figure A4.2. During the test, any switches within the equipment controlling primary power and likely to be operated in normal use are opened and closed in all possible combinations. Any components used for EMI suppression and connected between phase and earth are disconnected one at a time; for this purpose groups of components in parallel connected through a single connection are treated as single components.
Each time a line to earth component is disconnected, the sequence of switch operations is repeated. None of the current values shall exceed the relevant limit specified in table A4.1.
Class I stationary equipment that is permanently connected equipment, or that is pluggable equipment type B, with an earth leakage current exceeding 3.5 mA shall be subject to the following conditions: - The leakage current shall not exceed 5% of the output current per phase. Where the load is unbalanced the largest of the three-phase currents shall be used for this calculation. If necessary, the tests in A4.3 and A4.4 shall be used but with a measuring instrument of negligible impedance; - The cross - sectional area of the internal protective earthing conductor shall be not less than that of the power conductor, with a minimum of 1.0 mm2, in the path of high leakage current; - A label bearing the following warning, or similar wording, shall be affixed adjacent to the equipment primary power connection: “HIGH LEAKAGE CURRENT EARTH CONNECTION ESSENTIAL BEFORE CONNECTING SUPPLY” A5. Earth leakage current for equipment intended to be connected directly to IT power systems A5.1. General This annex provisionally covers the requirements for equipment to be connected directly to IT power systems. Equipment which meets these requirements will also meet the requirements, specified in A4, for connection to TT or TN power systems. Note: On an IT power system, the current which flows through the equipment safety earth conductor when it is correctly connected may be higher than for TT or TN power systems. The test procedures in this annex will, under the adopted conditions, determine the leakage current which could flow through a person in the event of accidental breakage of the equipment safety earth conductor. A5.2. Requirements Equipment shall not have earth leakage current in excess of the value in tabie A4.1 when measured as defined in clauses A5.3 or A5.4. Table A5.1: Maximum earth leakage current for equipment connected to IT power system
Systems of interconnected equipment with individual connection to primary power shall have each piece of equipment tested separately. Systems of interconnected equipment with one common connection to primary power shall be treated as a single piece of equipment. Equipment designed for multiple (redundant) supplies shall be tested with only one supply connected. If it is clear from a study of the circuit diagrams of class I permanently connected equipment or pluggable equipment type B that the earth leakage current will exceed 3.5 mA, but will not exceed 5% of input current, the test need not be made. If it is inconvenient to test equipment at the most unfavorable supply voltage, it is permitted to test at any available voltage within the rated voltage range or within the tolerance of rated voltage, and then calculate the results. A5.3. Single - phase equipment A5.3.1. Single - phase equipment intended for operation between one phase conductor and neutral is tested using the circuit of figure A5.1 with the selector switch of the positions 1, 2 and 3. A5.3.2. For each position of the selector switch, any switches within the equipment controlling primary power and likely to be operated in normal use are opened and closed in all possible combinations. None of the current values shall exceed the relevant limit specified in table A5.1. 
Figure A5.1: Test circuit for earth leakage current on single-phase equipment for connection to IT power systems A5.4. Three - phase equipment A5.4.1. Three phase equipment and equipment intended for operation between two phase conductors are tested under the following conditions, using the circuit of figure A5.2, with the selector switch of the positions 1, 2, 3 and 4. A5.4.2. For each position of the selector switch, any switches within the equipment controlling primary power and likely to be operated in normal use are opened and closed in all possible combinations. A5.4.3. In test of A5.4.2, Any components used for EMI suppression and connected between phase and earth are disconnected one at a time; for this purpose groups of components in parallel connected through a single connection are treated as single components. Each time a line to earth component is disconnected, the full sequence of A5.4.2 is repeated. Note: Where filters are normally encapsulated, it may be necessary to provide an uncapsulated unit for this test or to simulate the filter network. None of the current values shall exceed the relevant limit specified in table A5.1. 
Figure A5.2: Test circuit for earth leakage current on three-phase equipment for connection to IT power systems A5.5. Equipment with earth leakage exceeding 3.5 mA Class I stationary equipment that is permanently connected equipment, or that is pluggable equipment type B, with an earth leakage current exceeding 3.5 mA shall be subject to the following conditions: - The leakage current shall not exceed 5% of the input current per phase. Where the load is unbalanced the largest of the three-phase currents shall be used for this calculation. If necessary, the tests in A4.3 and A4.4 shall be used but with a measuring instrument of negligible impedance; - The cross - sectional area of the internal protective earthing conductor shall be not less than that of the power conductor, with a minimum of 1.0 mm2, in the path of high leakage current; - A label bearing the following warning, or similar wording, shall be affixed adjacent to the equipment primary power connection: “HIGH LEAKAGE CURRENT EARTH CONNECTION ESSENTIAL BEFORE CONNECTING SUPPLY” ANNEX B (Informative) MEASURING INSTRUMENT FOR LEAKAGE CURRENT TESTS Measuring instrument for leakage current tests (earth leakage current and leakage current to telecommunication network) has the circuit diagram as following: 
Figure B: Measuring instrument in leakage current test True r.m.s reading: - Uncertainty: ≤ 2% - Input resistance: ≥ 1 MΩ - Input capacitance: ≥ 200 μF - Frequency range: 15 Hz to 1 MHz Weighted leakage current = (Informative) IMPULSE TEST GENERATOR The circuit in figure C, using the component values in table C, is used to generate impulses, the C1, capacitor being charged initially to a voltage Uc. The impulse test circuit for the 10/700 s is that specified in ITU-T Recommendation K.17 to simulate lightning interference in telecommunication network. The impulse test circuit for the 1.2/50 s is that specified in ITU-T Recommendation K.21 to simulate transients in power distribution systems. Note: Extreme care is necessary when using these generators due to the high electric charge stored in the capacitor C1. 
Figure C: Impulse generating circuit Table C: Component values for impulse generating circuits
ANNEX D (Informative) CRITERIA FOR TELEPHONE RINGING SIGNALS
The two alternative methods described in this annex reflect satisfactory experience in different parts of the world. Method A is typical of analogue telephone networks in Europe, and Method B of those in North America. The two methods result in standards of electrical safety which are broadly equivalent. D2. Method A This method requires that the currents ITS1, and ITS2 flowing through a 5 kΩ resistor, between any two conductors or between one conductor and earth do not exceed the limits specified, as follows: a. ITS1, the effective current determined from the calculated or measured current for any single active ringing period t1 (as defined in figure D1), does not exceed: - For cadenced ringing (t1 < ∞), the current given by the curve of figure D1 at t1, or - For continuous ringing (t1 = ∞), 16 mA or 20 mA where cadenced ringing becomes continuous as a consequence of a single fault; where ITS1, in mA, is as given by:  (t1 ≤ 600 ms)
 (600 ms < t1 < 1200 ms)
 (t1 ≥ 1200 ms)
where:
Ip is the peak current, in mA; Ipp is the peak - to - peak current, in mA; t1 is expressed in ms. b. ITS2 the average current for repeated bursts of a cadenced ringing signal calculated for one ringing cadence cycle t2 (as defined in figure D1), does not exceed 16 mA r.m.s, where in mA, is as given by: 
where:
ITS1 in mA, is as given by a); Idc is the DC. current in mA flowing through the 5 kΩ resistor during the non - active period of the cadence cycle; t1 and t2 are expressed in ms. t1 is: - The duration of a single ringing period, where the ringing is active for the whole of the single ringing period; - The sum of the active periods of ringing within the single ringing period, where the single ringing period contains two or more discrete active periods of ringing, as in the example shown, for which t1 = t1a + t1b. t2 is duration of one complete cadence cycle.
This method is based on USA, CFR47 (“FCC Rules”) part 68, sub-part with additional requirements that apply under fault conditions. It requires that a ringing source shall meet the requirements of D3.1, D3.2 and D3.3. D3.1. Ringing signal D3.1.1. The ringing signal shall use only frequencies whose fundamental component is equal to or less than 70 Hz. D3.1.2. The ringing voltage shall be less than 300 V peak - to- peak and less than 200 V peak - to- earth, measured across a resistance of at least 1 MΩ. D3.1.3. The ringing voltage shall be interrupted to create quiet intervals of at least 1 s duration separated by no more than 5 s. During the quiet intervals, the voltage to earth shall not exceed 56.5 V. D3.2. Tripping device and monitoring voltage D3.2.1. Conditions for use of tripping device or monitoring voltage A ringing signal circuit shall include a tripping device as specified in D3.2.2, or provide a monitoring voltage as specified in D3.2.3, or both, depending on the current through a specified resistance connected between the ringing source and earth, as follows: - If current through a 500 Ω resistance does not exceed 100 mA peak - to -peak, neither a tripping device nor a monitoring voltage is required; - If the current through a 1500 Ω resistance exceeds 100 mA peak - to - peak, a tripping device shall be included. If the tripping device meets the trip criteria specified in D2 with R = 500 Ω, no monitoring voltage is required. If, however, the tripping device only meets the trip criteria with R = 1500 Ω, a monitoring voltage shall also be provided; - If the current through a 500 Ω exceeds 100 mA peak- to- peak, but the current through a 1500 Ω resistor does not exceed this value, either: + A tripping device shall be provided, meeting the trip criteria specified in figure D2 with R = 500 Ω, or + A monitoring voltage shall be provided.
- t is measured from the time of connection of the resistor R to the circuit. - The sloping part of the curve is defined as I = A series current-sensitive tripping device in the ring lead which will trip ringing as specified in figure D2. D3.2.3. Monitoring voltage A voltage to earth on the tip or ring conductor with a magnitude of at least 19 V peak, but not exceeding 56.5 V DC, whenever the ringing voltage is not present (idle state). D3.3. Fault conditions The ringing source shall meet the requirements of D3.1 and D3.2. D3.3.1. The current through a 5 k resistor shall not exceed 20 mA r.m.s when it is connected between: - Any two conductors; - Any one conductor and earth.
- The output conductor are connected together, or - Any conductor is connected to earth.
(Informative) TOOLS TO BE USED IN TESTS
Tolerances on dimensions without specific tolerances: For 14 and 37° angles: ±15’ On radii: ± 0,1mm On linear dimensions: + Up to 15 mm: 0 or -0.1 mm + Over 15 mm and up to 25 mm: ± 0.1 mm + Over 25 mm: ± 0.3 mm Material of finger: for example heated - treated steel
(Informative) NON-RADIO TELECOMMUNICATION TERMINAL EQUIPMENT INCLUDED IN THE SCOPE OF THE STANDARD
- Telephone sets; - Facsimile equipment; - Modems; - PABXs;
- Equipment which has combination of functions of the above... F2. Requirements
ANNEX G (Informative) CROSS - REFERENCE TABLE TO THE ORIGINAL STANDARDS
(*) EN 41003 (1996) (**) EN 60950 (amd.11, 1997) REFERENCES [9] EN 60950:1992, Specification for Safety of Information Technology Equipment, including Electrical Business Equipment, 1992 [10] EN 41003:1997, Particular Safety Requirements for Equipment to be connected to Telecommunications Networks, 1997 [11] ITU-T Recommendation K.51 (Draft Edition), Safety Criteria for Telecommunication Equipment, 1999. [12] ETSI Technical Report ETR 012, Terminal Equipment (TE) – Safety categories and protection levels at various interfaces for telecommunication equipment in customer premises, 1992 [13] TCVN 3256:1979, An toàn điện – Thuật ngữ và định nghĩa, 1979 [14] TCVN 3144:1979, Các sản phẩm kỹ thuật điện – Yêu cầu kỹ thuật [15] TCVN 5556:1991, Thiết bị điện hạ áp – Yêu cầu chung về bảo vệ chống điện giật, 1991 [16] TCVN 5699-1:1998, An toàn đối với thiết bị điện gia dụng và các thiết bị điện tương tự - Phần 1: Yêu cầu chung, 1998. Каталог: docs -> download download -> TIÊu chuẩn việt nam tcvn 5845: 1994 MÁy xay xát thóc gạo phưƠng pháp thử download -> TIÊu chuẩn quốc gia tcvn 8714: 2011 iso 25140: 2010 download -> Căn cứ Luật Tiêu chuẩn và Quy chuẩn kỹ thuật ngày 29/6/2006 download -> TIÊu chuẩn quốc gia tcvn 8940: 2011 download -> TIÊu chuẩn quốc gia tcvn 9964: 2014 download -> TIÊu chuẩn ngành 10 tcn 512: 2002 VỪng hạt yêu cầu kỹ thuật và phưƠng pháp thử Phạm VI áp dụng download -> TIÊu chuẩn quốc gia tcvn 8491-2 : 2011 download -> TỈnh thừa thiên huế download -> MỤc lục lời nói đầu I. Phạm VI và đối tượng áp dụng II. Các chữ viết tắt, định nghĩa và khái niệm download -> MỤc lục lời nói đầu Phạm VI và đối tượng áp dụng tải về 0.52 Mb. Chia sẻ với bạn bè của bạn:
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