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Wire
Termination :
Systematic
wiring in panel board requires a layout of properly selected
terminal blocks. In the normal course it would be appropriate to
assign one lead (wiring end) per clamping unit of terminal block.
This simplifies the task of identification / marking of the circuit.
However
while connecting two wires to one clamping unit of a screw clamp
terminal block care must be taken to ensure that the total current
assigned to two wires does not exceed the continuous rating of the
terminal block.
The
Screw Clamp Terminal Block can accommodate wire of one size higher
than the rated cross section. The Screw Clamp Terminal Blocks can
also accomodate two wires of one size smaller than the rated cross
section.
For
‘Screwless’ Spring Clamp Terminal Blocks, only one wire per
clamping unit must be strictly
followed.
The
relevant standard (IEC 60947-7-1, section 4.3.5) states that
for terminal blocks with rated cross section from 0.2 mm2 to 35 mm2
(inclusive) the manufacturer shall specify the range and / or number
of rated cross section. The conductor can be rigid (solid or multi
strand) or flexible (fine strand). These values may be found in
product related technical data. Connectwell feed through terminal
blocks are designed to allow copper wires to be connected without
any special preparation. Special preparation means soldering the
individual strands of wire ends or using cable lugs / ferrules. The
twisting of multi-strands or straightening of wire ends is not
considered as special preparation.The wires with special preparation
can also be connected in Connectwell terminal blocks - though not
necessary (as per IEC 60947-7-1) For connection of aluminum wire,
special care must be taken while stripping. It is
recommended
to strictly use ferrules and lugs while connecting flexible aluminum
wires. Having removed the necessary length of insulation, the wire
should be coated with acid and alkaline free Vaseline and screwed
into the terminal immediately. This procedure must be followed every
time aluminum wire is disconnected and reconnected.
In
applications where changing of connection in frequent, for avoiding
fracturing of
individual
wires and other specific applications, lugs / ferrules / cable
sockets may be used. The rated cross section of a terminal block is
a value of connectable conductor cross section, to which certain
thermal, mechanical and electrical requirements are referred to
relevant product standard.
Rated
Insulation Voltage with two wire / conductors
The
rated insulation voltage of the terminal block does not change if
the connection of wires / conductors are proper.
Wire
Tightening
Design
of Connectwell Screw Clamp / Cable Lug system ensures vibration
proof positive
connection wires at recommended torque values.
However
Connectwell Terminal Blocks can withstand torque levels in very much
excess of recommended
torque values.
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