Power Connection
Masterpact MTZ Electrical Equipment Cable Connections
If cables are used for the power connections, their weight must not be applied to the circuit breaker power terminals, but must be supported by the panel structure.
For this, make the connections as follows:
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Extend the device terminals using short bars designed and installed according to the recommendations for bar-type power connections (see figure below):
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For a single cable, use solution [1].
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For a multiple cables, use solution [2].
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In all cases, follow the general rules for connections to busbars:
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Position the cable lugs before inserting the bolts
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Firmly secure the cables to the framework [3].
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Busbar Connections
Install with a maximum distance A between busbar to circuit breaker connection and the first busbar support or spacer with respect to the value of the prospective short-circuit current.
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The busbars must be suitably adjusted so that the connection points are positioned on the power terminals before the bolts [4] are inserted.
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The busbars weight must be supported by the busbar supports [5] that are solidly fixed to the electrical equipment framework and not by the circuit breaker power terminals.
Electrodynamic Stresses
The first busbar support must be situated within the maximum distance (A) from the power terminal of the circuit breaker. This distance is required so that the busbar can withstand the electrodynamic stresses between phases in the event of a short circuit. The table below gives the maximum distance (A) according to the prospective short-circuit current Isc.
Maximum Distance (A) Based on Prospective Short Circuit Current
|
Maximum Distance A |
|
|
Short Circuit Current (kA) |
Maximum Distance A |
|
30 |
350 (13.8) |
|
50 |
300 (11.8) |
|
65 |
250 (9.84) |
|
80 |
150 (5.91) |
|
100 |
150 (5.91) |