Annex B Application Information for Ampacity Calculation

Annex B: AmpacitiesANNEX BDetail 1290 mm x 290 mm(11.5 in. x 11.5 in.)Electrical duct bankOne electrical duct.5LI)t:.ESl190 mm (7.5 in.)Detail 2475 mm x 475 mm(19 in. x 19 in.)Electrical duct bankThree electrical ductsor' , ­. ., , 'Il2WJ190 mm 190 mm(7.5 in.) (7.5 in.)675 mm x 290 mm(27 in. x 11.5 in.)Electrical duct bankThree electrical ducts600mm(24 in.)•DetailS Detail 6Buried 3 Buried 3conductorconductorcablecables190 mm 190 mm(7.rt1n .)1E--,.E.!:eLI)~r:::.190 mm (7.5 in.)Detail 3475 mm x 675 mm(19 in. x 27 in.)Electrical duct bankSix electrical ductsor190 mm 190 mm(7.5 in.) (7.5 in.)•••I ,675 mm x 475 mm(27 in. x 19 in.)Electrical duct bankDetail?Buried triplexedcables (1 circuit)E--,.E.!:eLI)~t::.A'. C(;).:.(;)~,~100 A. "... 0190 mm 190 mm(7.5 in.) (7.5 in.)Detail 4675 mm x 675 mm(27 in. x 27 in.)Electrical duct bankNine electrical ducts.~600mm(24 in.)J.Detail 8Buried triplexedcables (2 circuits)190mm190mm 190mm(7.5 in.) 600mm (7.5 in.) (7.5 in.)(24 in.)Detail 9Buried single-conductorcables (1 circuit)Detail 10Buried single-conductorcables (2 circuits)Note 1: Minimum burial depths to top electrical ducts or cables shall be inaccordance with 300.5. Maximum depth to the top of electrical ductbanks shall be 750 mm (30 in.) and maximum depth to the top ofdirect buried cables shall be 900 mm (36 in.)Note 2: For two and four electrical duct installations with electrical ductsinstalled in a single row, see B.310.15(B)(5).Legend~ Backfill~ (earth or concrete)o Electrical duct• Cable or cablesFigure B.310.2 Cable Installation Dimensions for Use withB.310.10.TableB.310.5 Through Table70-700NATIONAL ELECTRICAL CODE2008 Edition