In
selecting MCCB for a particular application, in addition to purely electrical
aspects of load and distribution conductor systems, physical factors such as panel
board configuration, installation environment, ambient-temperature variations, vibration,
etc. must also be considered. MCCB are rated for an ambient of 40ºC, and where panel board internal temperatures may exceed this, MCCB
installed should be derated in accordance with Table 5. 1.
1.
Actual load currents may exceed the nominal-values.
2.
Load current s may increase with time, due to deterioration of load devices
(i.e., friction in motors).
3.
Source voltage and frequency may vary.
Table 5. 1 MCCB Derating Due to Installation Factors
Fig. 5. 1 MCCB Selection Consideration
No comments:
Post a Comment