You can use #4 wire for 100 amp service, but it may not be the most ideal choice. The National Electrical Code (NEC) provides guidelines for wire sizing based on the ampacity of the circuit and the length of the wire run.
For a 100 amp service, the NEC typically recommends using 4 AWG or 2 AWG copper wiring, or 2 AWG, 1 AWG, or 1/0 AWG aluminum or copper-clad wiring. These larger wire sizes are necessary to ensure that the wire can safely carry the maximum current without overheating.
While #4 wire can technically handle 100 amps of current, it may not provide an adequate safety margin. It’s important to consider factors such as voltage drop, wire length, and the type of load being served. Using a larger wire size can help minimize voltage drop and ensure efficient power delivery.
Personal experience: In my own electrical projects, I have encountered situations where using a smaller wire size than recommended led to issues such as excessive voltage drop and overheating. It’s always better to err on the side of caution and use the appropriate wire size for the intended load.
To summarize, while #4 wire can technically handle 100 amps, it may not be the best choice for a 100 amp service. It’s recommended to consult the NEC guidelines and consider factors such as voltage drop and wire length to determine the appropriate wire size for your specific application.