Nec Service Entrance Wiring Diagram. 511 240 volt 3 phase 3 wire b phase grounded 512 120208 volt 1 phase 3 wire contact local operating office for information 52 approved sockets. Service size service entrance conduit per iecnec service entrance conductors see notes below grounding service cu only riser entrance run residential 1φ 3w 120240v all other services 100 amps 2 inch see 16 1 ½ or 2 inch 4 cu 3 cu 8 2 al 1 al 200 amps 2 ½ inch see 16 2 inch 20 cu 30 cu 4 2 ½ inch 40 al 250 kcm al 320400 amps 3 inch see 16.
Service drop an overhead power connection from the utility lines to the service entrance is called the service drop. Service entrance cable shall be permitted for use where the insulated conductors are used for circuit wiring and the uninsulated conductor is used only for equipment grounding purposes. Nonmetallic sheathed cable is a common wiring method used for residential and commercial branch circuits.
Wire size load ampacity 652 amp 815 amp 8 use nec 310 16 75c thw wire 4 wire has 85 amps use 4 2 4 and 1 4 ground circuit breaker sizing cb load 652 amp 815 amp 8 8 next higher cb size is 90 amp.
How to inspect the electrical service entry wiring for components that limit the electrical service ampacity available to the building a 200 amp main panel does not itself assure that 200a is available. The nec article 23070a states that a disconnecting means for the main service must be located either outside or inside the building nearest the point of entrance of the service conductors. Service drop an overhead power connection from the utility lines to the service entrance is called the service drop. Service entrance equipment the service entrance conductors raceway and fittings or service entrance cable and fittings which are installed on the customers premises to connect the electric service to the wiring inside the building.