Table of Contents
Advertisement
13.11 Taking the withdrawable circuit-breaker / fuse combination out of a panel or inserting in a panel
The procedure for inserting and/or removing the withdrawable circuit-breaker / fuse combination in the circuit-
breaker panel with HV HRC fuse is identical with the procedure for inserting and/or removing the
withdrawable circuit-breaker in the circuit-breaker panel.
For inserting and/or removing the withdrawable circuit-breaker / fuse combination in the
circuit-breaker panel with HV HRC fuse, see chapter 10.20 and/or 10.19
13.12 Replacement of HV HRC fuse-links
According to IEC 60282-1 (2009) Clause 6.6, the breaking capacity of HV HRC fuses is tested within the
scope of the type test at 87% of their rated voltage.
In three-phase systems with resonance-earthed or isolated neutral, under double earth fault and other
conditions, the full phase-to-phase voltage may be available at the HV HRC fuse during breaking. Depending
on the size of the operating voltage of such a system, this applied voltage may then exceed 87% of the rated
voltage.
It must therefore already be ensured during configuration of the switching devices and selection of the
HV HRC fuse that only such fuse-links are used, which either satisfy the above operating conditions, or
whose breaking capacity was tested at least with the maximum system voltage.
In case of doubt, a suitable HV HRC fuse must be selected together with the fuse manufacturer.
Arrangement of HV HRC fuse-links
Circuit breaker / fuse combination is equipped with single fuse-link arrangement per phase.
139-2021.9 / 07
Operating the circuit-breaker panel with HV HRC fuse
CAUTION
Burns
After tripping, the surfaces of HV HRC fuse-links are hot. Touching hot HV HRC
fuse-links may cause burns.
Put on personal protective equipment.
Let hot HV HRC fuse-links cool down before replacing.
NOTICE
Undetected damage
Even if the withdrawable circuit breaker / fuse combination shows no visible
damages of a fault, the HV HRC fuse-link may have tripped due to a fault.
Check the switching-device compartment for deformations when a fuse-
link has tripped.
NXAIR M
89
Advertisement
Table of Contents
