Power Installation
Table of contents1. Grouping of Cables
Continuously load carrying cables shall be horizontally spaced on trays, ladders and racks with control or other non load carrying cables in between. Control cables shall be laid between power cables to the maximum extent possible.
Only two layers of continuously load carrying cables (including non load carrying cables in between) in one tray are allowed. Non load carrying cables only may be bunched into more layers in a tray.
Single core cables forming a 3 phase circuit shall be installed in specially made cable cleats which in their turn are fixed to a mild steel supporting base in single or multiple tiers (see below detail 7). To avoid heating from induction continuous magnetic circuits shall not be allowed.
Single core cables installed in cleats shall be run on separate trays or racks.
2. Connection of Cable Conductors
Where cable cores are connected to terminals an additional core length of approx. 8 cm shall be kept which shall be worked-off as a “pigtail” before the terminal blocks.
Cores of the same cable shall be tied-up over the maximum possible length by means of binding cord or strap or where available be installed in wiring ducts. Unused cores shall not be cut-off but bundled for future use.
Stranded cores shall be connected with compression type cable lugs or wire pins when the receiving terminals are not suitable for stranded cores.
Two or more cores may never be connected to the same terminal unless it has special provisions for that.
Splices in control, alarm and safety interlock circuits are not allowed.
Motors, outlets, switchgears, meters, etc., shall be so connected that the phase rotation, cable core colours and polarity are consistent throughout the entire project.
The actual colours or markings of cable cores as used shall be recorded and marked up by Contractor on the “as built” drawings.
3. Cable Marking
All cables other than lighting branch-circuit cables shall be identified with cable markers. For system of cable identification see standard BN-DS-E4.
All cable markers shall be made and supplied by Contractor.
4. Miscellaneous Requirements
A lockable safety switch shall be located close to electrical rotating equipment that could cause danger to maintenance personnel. (i.e. air fin drives, mixers in enclosed vessels provided with manholes, etc.
Warning plates shall be supplied and installed by Contractor where electric motors can be started automatically from elsewhere.
Control stations for high voltage motors (if not fuse protected) shall be located opposite the motor connection box.
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