IEC 60282-1-2020 pdf download.High-voltage fuses — Part 1: Current-limitIng fuses
Fusibles a haute tension — Partle 1: Fusibles limiteurs de courant.
5.3.5.2 Maximum body temperature under pre-arcing conditions
For Back-Up fuses intended for use in striker-tripped fuse-switch combinations according to IEC 62271-105. the fuse manufacturer shall define the maximum body temperature that may be reached with any current above the minimum melting current, and the corresponding current value.
A procedure to determine this temperature and current value is given in 8.3.3.2. In the case of homogeneous series, It is sufficient to perform the test on the fuse having the highest current rating.
5.3.5.3 Maximum arcing withstand time
The arcing withstand time is the time between the beginning of the arcing and the occurrence of external damage to the fuse. The fuse manufacturer shall provide information regarding the maximum arcing withstand time, at a current value between 70 % and 100 % of rated minimum breaking current.
This time shall be at least 0,1 s. The testing procedure is described in 8.3.3.3.
5.3.6 Allowable continuous current of a fuse-link (‘i)
The current assigned to a fuse-link that a new clean fuse-link will carry continuously, at a specified surrounding temperature, without exceeding specified maximum temperatures when mounted as specified by the manufacturer. The surrounding temperature may exceed 40 °C (see IEC TR 62655:20 13).
NOTE It is possible for allowable continuous current values to be higher than, equal to. or lower than the assigned rated current (I,). For example, higher values of allowable continuous current are primarily associated with certain fuse designs, while the more usual situation of lower values of allowable continuous current are normally associated with elevated surrounding temperatures andlor specific application conditions II is also possible for a particular fuse-link to have several allowable continuous currents specified (eg each at a different surrounding temperature) or to have allowable continuous current defined by a formula related to surrounding temperature.
5.3.7 Maximum enclosure current (Itep)
The current assigned to a fuse-link by the FEP manufacturer that a new clean fuse-link will carry continuously, at a specified surrounding temperature above 40 °C, when mounted as specified by the manufacturer and immersed In liquid. A fuse-link will have multiple values of ‘fep depending on the enclosure and surrounding temperature. (See IECITR 62655:2013.) The
maximum values of temperature given in Table 6 may be exceeded, but only by agreement between the manufacturer and user. The maximum enclosure current is used for the liquid tightness test (8.3.4).
6.1.2 Standard conditions of use
Testing specified in this document is intended to demonstrate the suitability of a fuse for use
under the following conditions:
a) the AC component of current is not higher than the rated maximum breaking current;
b) the AC component of a current that the fuse is intended to interrupt is not lower than:
— the rated minimum breaking current for a Back-Up fuse;
— the current that causes melting in 1 h for a General-Purpose fuse;
– the rated current for a Full-Range ruse;
c) the surrounding temperature is not higher than the maximum application temperature (MAT), for fuses that have been assigned a MAT. In the case of a Full-Range fuse that has an assigned MAT, there is no low current restriction:
d) the highest system voltage is not greater than the rated voltage of the fuse-link, if used in a three-phase solidly earthed neutral system or low impedance — or low resistanceearthed neutral system;
e) the highest system voltage is not greater than 87 % of the rated voltage of the fuse-link, if used in a three-phase isolated neutral system or a resonant earthed system and the fuse- links have been tested to Series I voltage in accordance with Table 11. This is because a double earth fault (with one fault on the supply side and one fault on the load side of a fuse on another phase) can occur.
It may be noted that a higher maximum system voltage than 87 % of the rated voltage of the fuse-link is acceptable when additional or alternative tests have been performed on the fuse (see IEC TR 62655:2013, 5.1.3.3);
f) the highest single-phase voltage to which the fuse-link is subjected during and after current interruption is not greater than 87 % of the rated voltage of the fuse-link, if used on a single-phase application and the fuse-links have been tested to a Series I voltage and in accordance with Table 11.
It may be noted that a higher maximum voltage than 87 % of the rated voltage of the fuse- link is acceptable when additional or alternative tests have been performed on the fuse (see IEC TR 62655:2013, 5.1.3.3);
g) the highest system voltage on a three-phase system or single-phase voltage on a singlephase application Is not greater than the rated voltage of the fuse-link, if the fuse-link has been tested to a Series II voltage and in accordance with Table 11, footnote b;
h) the prospective transient recovery voltage is within the limits represented by the tests specified in 7.6.1.4;
i) the frequency is between 48 Hz and 62 Hz;IEC 60282-1-2020 pdf download.