Site Preparation
7750 SR-a4 and SR-a8 Installation Guide 51
Notes:
1. Short-term refers to no more than 96 consecutive hours per occurrence and no more than 15 occurrences in 
a one-year period.
2. Pollution degree is as defined in IEC 60950. Pollution Degree 2 applies where there is only non-conductive 
pollution that might temporarily become conductive due to occasional condensation.
Earthquake Suitable for high-risk areas (Zone 4/California, for 
short-duration disturbance)
Pollution degree
2
2
Rated voltage (DC)  –48 VDC
Operating voltage range (DC)  –40 to –72 VDC 
Rated voltage (AC)  120 or 240 VAC 
Operating voltage range (AC) 
90 to 264 VAC
 
Table 15: 7750 SR-a4 Environmental Specifications  (Continued)
Parameter Description
Table 16: 7750 SR-a8 Environmental Specifications 
Parameter Description
Normal operating temperature 23 to 113ºF (–5 to 45ºC)
Short-term operating temperature
1
23 to 131ºF (–5 to 55ºC)
Maximum altitude 13 000 ft (3962.4 m)
Normal operating relative humidity 5 to 90% (non-condensing)
Short-term operating relative humidity
1
5 to 93% (non-condensing)
Acoustic noise level  78 dBA at 27ºC (80.6ºF). Fan speed is adaptive. 
Shock and vibration Very low levels for continuous duration disturbance (similar 
to modern office Building, for example)
Shock: 3 g half sine 11 ms
Vibration: 0.1 g from 5 to 100 Hz
Earthquake Suitable for high-risk areas (Zone 4/California, for 
short-duration disturbance)
Pollution degree
2
2