CEl IEC 60255-5:2000 pdf download

CEl IEC 60255-5:2000 pdf download.Electrical relays -Part 5: lnsulation coordination for measuring relaysand protection equipment-Requirements and tests.
3.5
creepage distance
shortest distance along the surface of the insulating material between two conductive parts
[1EV 151 -03-37]
3.6
rated voltage
value of voltage assigned by the manufacturer to a component, device or equipment and to which operation and performance characteristics are referred
[lEG 60664-1]
3.7
rated insulation voltage
r.m.s. withstand voltage value assigned by the manufacturer to the re’ay or to a part of it, characterising the specified (long term) withstand capability of its insulation and to which dielectric tests and creepage distances are referred
NOTE The rated insulation voltage is not necessarily equal to the rated voltage of equipment which is primarily related to functional performance.
3.8
rated impulse voltage
impulse withstand voltage value assigned by the manufacturer to the relay or to a part of it, characterising the specified withstand capability of its insulation against transient over- voltages and to which clearances are referred
3.9
overvoltage
any voltage having a peak value exceeding the corresponding peak value of the maximum steady-state voltage at normal operating conditions
[lEG 60664-1]
overvoltage category
numeral defining a transient overvoltage condition
[lEG 60664-1]
NOTE Overvoltage categories I, II, Ill, IV are used, see 4.2.2.1.
macro-environment
environment of the room or other location in which the relay is installed or used
[IEC 60664-1]
3.12
micro-environment
immediate environment of the insulation which particularly influences the dimensioning of the creepage distances
[lEG 60664-1]
3.13
pollution
any addition of foreign matter, solid, liquid or gaseous, that can result in a reduction of electric strength or surface resistivity of the insulation
[lEG 60664-1]
3.14
pollution degree
numeral characterising the expected pollution of the micro-environment
[IEC 60664-1]
NOTE Degrees 1 to 4 are defined in 4.4.
tracking
progressive formation of conductive paths which are produced on the surface of solid insulating material due to the combined effects of electric stress and electrolytic contamination on the surface
3.16
comparative tracking index
figure that characterises the relative tracking performance of insulating materials
3.17
type test
test of one or more devices made to a certain design to show that the design meets certain specifications
[1EV 151-04-151
3.18
routine test
test to which each individual device is subjected during or after manufacture to ascertain whether it complies with certain criteria
[1EV 151-04-16]
3.19
dielectric test
test of short duration which consists in applying a specified voltage to the insulation to prove that it is in accordance with the rated insulation voltage of the circuit, as stated by the manufacturer
3.20
impulse voltage withstand test
test which consists in applying a specified impulse voltage to the insulation to prove the ability of the measuring relay or protection equipment to withstand without damage overvoltages of very high values and very short duration
3.21
functional insulation
insulation between conductive parts which is necessary only for the proper functioning of the relay
[IEC 60664-1]
3.22
basic insulation
insulation applied to live parts to provide basic protection against electric shock
[IEC 60664-1]
NOTE Basic insulation does not necessarily include insulation used exclusively for functional purposes.
3.23
supplementary insulation
independent insulation applied in addition to basic insulation, in order to provide protection against electric shock in the event of a failure of basic insulation
[IEC 60664-1]
3.24
double insulation
insulation comprising both basic insulation and supplementary insulation
[IEC 60664-1]
3.25
reinforced insulation
single insulation system applied to live parts, which provides a degree of protection against electric shock equivalent to double insulation under conditions specified in the relevant IEC standard
[IEC 60664-1]
NOTE A single insulation system does not imply that the insulation must be one homogeneous piece. It may comprise several layers which cannot be tested singly as basic or supplementary insulation.
4 Insulation coordination
4.1 Basic principles
The basic principles of insulation coordination are stated in IEC 60664-1 which provides guidance for the specification and testing of clearances, creepage distances and solid insulation.
NOTE The standard insulation for relays is basic insulation. However, there are cases of application in which a
higher level of insulation (e.g. supplementary, reinforced or double insulation) is required. For example, a
communication port connected to a modem may require double insulation.
Clearances shall be dimensioned according to expected overvoltages at the place of installation.
The following design parameters shall be considered:
— overvoltage category;
— pollution degree;
— geometry of clearances;
— nominal voltage from which the rated insulation voltage is derived.