L. T. CONTROL CABLES
For easy and convenient installation conditions and desired performance, we recommend
the following suggestions :
-
No drums should be stacked; i.e. stored one above the other.
-
Drums should be stored on a flat ground surface without any projected hard stones
above the ground surface; preferably in sheds.
- Drums should be stored and placed in such a way that bottom cable end is not
damaged.
- Drums should be rotated only in a direction marked on the drum.
- While laying the cable in a trench, the cable end should be pulled with a pulling
eye only after mounting the drum on the jacks.
- Drums shall be checked thoroughly for continuity and cross continuity, to ensure
that there is no internal damage to cable during transportation.
- Insulation resistance shall be measured with 500 V. Megger between the cores
and all the cores to earth ( Armoured ).
- After the cable is installed, before commissioning it shall be tested for high
DC voltage test. The recommended volts and duration of test between each core and
the metallic armour (earth) at 3 KVDC is for 5 minutes. During High Voltage test
all the electrical equipments related to the cable installation must be earthed
and adequate clearance should be maintained from the other equipments and work to
prevent flash over.
- Where the cable is to be joined with an existing cable, the sequence of cores
at the two ends to be joined should be in the opposite direction i.e. if at one
end the sequence of cores is in the clockwise direction, then at the other end the
sequence of cores should be in the anti-clockwise direction. This is necessary to
avoid the crossing of cores while joining. This will also decide the direction in
which the cable is to be pulled.
- The minimum bending radius for cable should not be less than the values given
below. Wherever possible, 25% higher value should be adopted.
8 X Overall Diameter: Single core as per table I
12 X Overall Diameter: Multi core as per table II and table III
- Avoid excessively high temperature when sealing joints of cable. Cool the sealant
to about 100° C before pouring.