Emerson Static Transfer Switch Recommended Minimum Service Clearances, Heat Output, Heat output

Location Considerations

3.0LOCATION CONSIDERATIONS

The Liebert STS2 should be placed in a clean, cool and dry location. The Liebert STS2 requires only front access for installation and maintenance. Back or side access is not required. Adequate space is required above the unit for conduit (if configured as such) and cooling air flow. This section provides specific information for these considerations.

The unit is designed with top and bottom cable terminations to allow maximum flexibility in its installation. If bottom cable entry is used, sufficient cable bending space must be provided by a raised floor or a floor stand.

For dimensions of each unit, see Figures 5, 6 and 7 in section 7.0 - Installation Drawings on page 18. If your unit is equipped with an optional key lockout switch, see Figures 8 through 10 for location of that switch.

3.1Recommended Minimum Service Clearances

The recommended service clearances are at the front of the unit. The minimum service clearance required by the National Electrical Code (NEC) Article 110-26 is 36 in. (91 cm) for units with voltages up to 150V to ground and 42 in. (107 cm) for units with voltages over 150V to ground. Clearance of at least 18 in. (46 cm) is required above the unit for cooling air flow.

3.2Heat Output

The unit produces minimal heat during normal operation.

Table 1	Heat output
		Heat Output
Switch Size		BTU/Hr (kW)
100 amp		2,711 (0.80)
250 amp		4,680 (1.37)
400 amp		6,972 (2.04)
600 amp		10,520 (3.08)
800 amp		13,777 (4.03)
1000 amp		17,390 (5.09)

3.3Operating Environment

The unit is designed to be installed indoors where the ambient air temperature is in the range of 32° and 104°F (0°C and 40°C) with a relative humidity of 0% to 95% non-condensing, up to an altitude of 4000 feet (1200 meters).

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