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Upstream and Downstream Protection for IEC

DANGER
Hazard of electric shock, explosion, or arc flash
  • Circuit breakers must have instantaneous trip time of maximum 60 ms.
  • Circuit breakers must have instantaneous override values set according to the table below.
  • Circuit breakers must be installed for input (unit input breaker UIB) and bypass (static switch input breaker SSIB).
  • Circuit breakers must be installed for the output (unit output breaker UOB) of each UPS in a parallel system.
Failure to follow these instructions will result in death or serious injury.
NOTE: For local directives which require 4-pole circuit breakers: If neutral conductor is expected to carry a high current, due to line-neutral non-linear load, the circuit breaker must be rated according to expected neutral current.

Recommended Upstream Protection for IEC

UPS rating 200 kW 250 kW
  Input Bypass Input Bypass
Breaker type NSX400H Mic 2.2 (LV432695) NSX400H Mic 2.2 (LV432695) NSX630H Mic 2.2 (LV432895) NSX400H Mic 2.2 (LV432695)
Io 400 320 500 400
Ir 1 1 1 1
Isd ≤10 ≤10 ≤10 ≤10
UPS rating 300 kW 350 kW 400 kW
  Input Bypass Input Bypass Input Bypass
Breaker type NSX630H Mic 2.2 (LV432895) NSX630H Mic 2.2 (LV432895) NS800H Mic 5.0 (33553) NSX630H Mic 2.2 (LV432895) NS800H Mic 5.0 (33553) NSX630H Mic 2.2 (LV432895)
Io 1 1 0.8 0.96 0.95 1
Ir 570 500 570 630
tr ≥4 ≥4
li (x In) ≤10 ≤10
Isd ≤10 ≤10 ≤10 ≤10 ≤10 ≤10
UPS rating 450 kW 500 kW
  Input Bypass Input Bypass
Breaker type NS1000H Mic 5.0 (33559) NS800H Mic 5.0 (33553) NS1000H Mic 5.0 (33559) NS800H Mic 5.0 (33553)
Ir 0.9 0.9 0.95 0.95
tr ≥4 ≥4 ≥4 ≥4
li (x In) ≤8 ≤10 ≤8 ≤10

Recommended Downstream Protection for IEC

NOTE: The recommended downstream protection given below is not valid for tripping the breaker when the UPS is in battery operation, only for tripping the breaker when the UPS is in static bypass operation.
UPS rating 200 kW 250 kW 300 kW 350 kW 400 kW 450 kW 500 kW
Breaker type NSX160H Mic 2.2 NSX250H Mic 2.2
Ir 160 250
Isd 10 10
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