electrical services minimum requirement - NSW Public Works
electrical services minimum requirement - NSW Public Works
electrical services minimum requirement - NSW Public Works
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Part 2 - Switchboards and Associated Equipment<br />
Fuses shall be suitable for the fault level of the installation and shall discriminate properly<br />
with other protective equipment. Let-through energy and peak current cut-off shall suit<br />
the protected equipment.<br />
Fault current limiter fuse links shall be held in proprietary holders, and shall be mounted<br />
for withdrawal directly towards the operator. Holders for open blade type fuses shall have<br />
barriers complying with Clause 204.6.1.<br />
Where fuse extraction handles are required, they shall be clipped inside the switchboard<br />
cubicle adjacent to the fuses. Where the fuses are located behind more than one cover,<br />
one handle shall be provided behind each cover.<br />
Fuse links shall clearly state the name of the Australian manufacturer or distributor.<br />
A <strong>minimum</strong> of three spare fuse links shall be provided for every fuse size included in the<br />
switchboard, with the exception of fuses installed solely for fault current limiting. The<br />
spare fuse links shall be mounted in clips in the spare parts cabinet or space described in<br />
Clause 214, and where more than one size is provided, rating labels shall be fitted.<br />
207.6 Fuse Combination Units<br />
Fuse combination units shall comply with AS 1775 and shall incorporate the following<br />
features:<br />
(a) Be either of the totally enclosed type or constructed such that the fixed live parts of<br />
the switches and fuses are fully and directly shrouded to prevent faults developing<br />
between phases by introduction of a foreign straight metallic object. The shrouding<br />
shall be fully effective throughout the entire movement of the air break switch.<br />
(b) Switching shall be "independent manual operation".<br />
(c) Rating duty shall be "uninterrupted type".<br />
(d) Derating shall be applied, if appropriate, for units mounted in a compact formation<br />
(eg stacked formation).<br />
(e) Utilisation category shall be in general AC-21 <strong>minimum</strong>, with AC-23 for motor<br />
loads.<br />
(f) Ability to be padlocked in the open position, if indicated.<br />
(g) Contact position shall be clearly shown both with the cover in place and with the<br />
cover removed. A secondary indication independent of the handle position shall<br />
additionally be provided. Where the fuses are mounted in a withdrawable carriage<br />
which ensures isolation from the supply before access to the fuses is possible,<br />
then the secondary indication may be omitted.<br />
(h) Identification of the contact position shall be clearly marked on the F.C.U. in a<br />
contrasting colour.<br />
207.7 Main Switches<br />
This clause shall apply to main switches on main switchboards and local main switches<br />
on distribution boards.<br />
Main switches shall comply with AS 1775 and shall be suitable for fault-making/loadbreaking<br />
duties. Suitable switches are automatic circuit breakers, fused F.C.U.'s and<br />
fault-making/load-breaking switches.<br />
Non-automatic breakers, F.C.U.'s with solid links, or load-making/load-breaking style<br />
switches are not acceptable unless they have been tested for fault-making/load-breaking<br />
duties to AS 1775.<br />
The following features shall be incorporated:<br />
(a) Type of switching shall be "independent manual operation".<br />
(b) Rated duty shall be "uninterrupted type" for a non-ventilated enclosure.<br />
Page 44 MEW E101