Load Center Number of Spaces 40 Amps 225 A Voltage 120/240V AC Circuit Breaker Type QO Included Enclosure Cover Order Separately Main Circuit Breaker or Main Lug Main Circuit Breaker Max No of Tandem Breakers 20 Phase 1 Height 37.98 in Width 14.25 in Depth 3 3/4 in For Use With Square D QO Circuit Breakers Short Circuit Current Rating 22 kA Enclosure NEMA Rating 1 Color Gray Max Operating Temp 104 Degrees F Min Operating Temp 23 Degrees F Special Features Mercury Free