56
The system must be equal potentially earthed. The earth device must comply with both system anti-interference and electrical safety requirements, and
not short-circuit or mixed with zero line of strong current grid. When the system is individually earthed, its earth impedance should be not more than 4
Ω
,
with the section area of earth conductor not more than 25mm
2
.
Annex
Ⅳ
: Maintenance of the terms of service
1
、
Warranty terms
Within one year after delivered, if found any defects caused by materials or workmanships, the factory shall be responsible for free repair or replace;
The warranty period of all repaired or replaced parts shall be 90 days since delivered;
