Yes, it is dangerous and not compliant with electrical codes to use 14-2 wire for a 20-amp circuit, such as a dishwasher or any other appliance requiring a 20-amp circuit. The wire gauge and amperage rating must match to ensure the safety and proper functioning of the electrical circuit.
The "14-2" designation refers to a specific type of electrical wire, where "14" indicates the wire gauge (AWG) and "2" means it has two conductors (a black "hot" wire and a white "neutral" wire) along with a ground wire (usually bare or green). 14-gauge wire is rated for 15 amps, and 12-gauge wire is rated for 20 amps.
Using 14-2 wire on a 20-amp circuit can lead to several problems:
Overloading the Wire: A 20-amp circuit can draw more current than a 14-gauge wire can handle. This can cause the wire to overheat and potentially lead to a fire.
Tripping Circuit Breakers: If the circuit is properly protected by a 20-amp circuit breaker (as it should be), using 14-gauge wire will likely cause the breaker to trip regularly, as it is not designed to handle the higher current demands.
Electrical Code Violation: National Electrical Code (NEC) and local building codes mandate that the wire gauge used must match the amperage rating of the circuit to ensure safety and compliance.
For a 20-amp circuit, you should use 12-2 wire, which is rated to handle the higher current safely. If you're unsure about electrical work, it's always best to consult a licensed electrician to ensure that the wiring is done correctly and meets all safety standards. Electrical work can be hazardous if not done properly, so it's essential to prioritize safety.