Table of Contents
2 Normative references
4 TNV circuits
4.1 TNV-0 circuits
4.2 TNV-1, TNV-2 and TNV-3 circuits
5 Protection of telecommunication network service
personnel, and users of other equipment connected to
the network, from hazards in the equipment
5.2 Use of protective earthing
5.3 Separation of the telecommunication network
5.4 Limitation of the touch current to a
6 Protection of equipment users from overvoltages on
6.1 Separation requirements
6.2 Electric strength test procedure
7 Protection of the telecommunication wiring system from
Annex A (normative) Criteria for telephone ringing signals
Annex B (normative) Impulse test generator (see 6.2.1)
Annex C (informative) Procedure for impulse testing (see
Figure 1 - Maximum voltages permitted after a single fault
Figure 2 - Test generator
Figure 3 - Test probe
Figure 4 - Test for separation between a telecommunication
network and earth
Figure 5 - Test circuit for touch current of single-phase
equipment on a star TN to TT power supply system
Figure 6 - Test circuit for touch current of three-phase
equipment on a star TN or TT power supply system
Figure 7 - Application points of test voltage
Figure A.1 - Definition of ringing period and cadence cycle
Figure A.2 - ITS1 limit curve for cadenced ringing signal
Figure A.3 - Peak and peak-to-peak currents
Figure A.4 - Ringing voltage trip criteria
Figure B.1 - Impulse generating circuit
Figure C.1 - Waveform on insulation without surge suppressors
and no breakdown
Figure C.2 - Waveforms on insulation during breakdown without
Figure C.3 - Waveforms on insulation with surge suppressors
Figure C.4 - Waveform on short-circuited surge suppressor and
Table 1 - Voltage ranges of TNV circuits
Table 2 - Separation of TNV circuits
Applicable to equipment designed and intended to be connected directly to a Telecommunication Network, regardless of the source of power. This basic safety publication is primarily intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51. It is not intended for use by manufacturers or certification bodies. This standard has the status of a basic safety publication in accordance with IEC Guide 104 and ISO/IEC guide 51. This standard cancels and replaces IEC Guide 105 published in 1985. The contents of the corrigenda of March 2001 and June 2001 have been included in this copy.
This International Standard is applicable to equipment designed and intended to be connected directly to a TELECOMMUNICATION NETWORK, regardless of the source of power.
It is intended for the enhancement of product safety standards so as to cover hazards associated only with connection of equipment to a TELECOMMUNICATION NETWORK.
This standard covers safety requirements and compliance criteria under three headings:
a) protection of SERVICE PERSONNEL working on the TELECOMMUNICATION NETWORK and other USERS of the TELECOMMUNICATION NETWORK, from hazardous conditions on the TELECOMMUNICATION NETWORK resulting from the connection of the equipment;
b) protection of equipment USERS and equipment SERVICE PERSONNEL from voltages on the TELECOMMUNICATION NETWORK;
c) protection of the telecommunication wiring system from overheating.
It is assumed that adequate measures according to ITU-T Recommendation K.11 have been taken to reduce the likelihood that the overvoltages presented to the equipment exceed 1,5 kV peak. In installations where overvoltages presented to the equipment may exceed 1,5 kV peak, additional measures such as surge suppression may be necessary.
Requirements additional to those specified in this standard may be necessary for:
equipment intended for operation in special environments, for example, extremes of temperature; excessive dust, moisture, or vibration; flammable gases; and corrosive or explosive atmospheres;
electromedical applications with physical connections to the patient.
This standard does not apply to:
protection of equipment USERS and equipment SERVICE PERSONNEL from hazards arising in the equipment. The USER and equipment SERVICE PERSONNEL are considered to be protected from hazards arising in the equipment if it complies with a relevant safety standard;
functional reliability of equipment and TELECOMMUNICATION NETWORKS;
- equipment using a TELECOMMUNICATION NETWORK voltage in excess of the limits for a TNV
This basic safety publication is primarily intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51. It is not intended for use by manufacturers or certification bodies.
One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications. The requirements, test methods or test conditions of this basic safety publication will not apply unless specifically referred to or included in the relevant publications.
Where the requirements of this standard differ from the requirements of the relevant safety standard, the requirements of the relevant safety standard take precedence.
Where this publication specifies the use of BASIC INSULATION, and other grades of insulation, or PROTECTIVE EARTHING, the detailed requirements of the relevant product safety standard apply.
2000 COR 2 2001 [01/06/2001]
2000 COR 1 2001 [01/03/2001]
1ED 2000 [01/05/2000]