For Cu AC wires:
Delta recommends the AC cables used should be flexible unarmored multi-strand
and with suitable ampacity.
For Al AC wires:
To make sure good conductivity, bi-metal sleeves must be used in conjunction
with aluminum wires. (Shown as Figure 4-4)
Figure 4-4 : Bi-metal sleeves
Al
Cu
Extreme temperature rise at the clamping point
If the contact resistance between the aluminum conductor and clamping point is too
high, the clamping point can become very hot and even catch fire in extreme cases.
To ensure a safe and reliable contact, always perform the following work steps:
Use a conductor cross-section at least one number larger due to the lower
current-carrying capacity.
Keep the installation location as free as possible from moisture or corrosive
atmospheres.
Connect the aluminum cables quickly.
Mechanically clean the stripped end of the aluminum conductor (using for instance
a knife blade to scrape off the oxide layer). Then immediately dip the aluminum
conductor into acid-fee and alkaline-free (=neutral) Vaseline and straight away
insert it into the terminal block.
Tighten the clamping screw in the clamping body with the maximum permissible
tightening torque.
NOTICE
23
Wiring
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