Eaton 276277 4 pin circuit breaker with isolator for distribution board eaton 276277 p the eaton 276277 is a 4 pin circuit breaker with isolator for a distribution board rated at 63a 240v ac 415v ac the circuit breaker has a compact mounting depth of 70mm making it ideal for installation in distribution boards in residential and non residential buildings as well as schools commercial buildings and shops the contacts are resistant to high wear and tear p eaton 276277 main switch 4 pin