Q. On a 3-phase, 4-wire, 277V multi-wire lighting circuit, which is protected at 20A, there is debate as to the proper application of 210.4(B) and 240.15(B). The question is whether or not three single-pole circuit breakers with an identified handle tie are permitted to serve as both the disconnecting means and the overcurrent protective device for this circuit, or whether a multi-pole circuit breaker is required. What is the correct answer?
- Circuit breakers installed with identified handle ties are permitted to serve as both the disconnecting means and overcurrent protection as stated in this example.
- Circuit breakers may be installed with or without identified handle ties to serve as the overcurrent protective device only (not as the disconnecting means).
- A multi-pole circuit breaker may serve as both the disconnecting means and overcurrent protective device.
- All the above are correct answers.
As per 210.4(B), “Each multi-wire branch circuit shall be provided with a means that will simultaneously disconnect all ungrounded conductors at the point where the branch circuit originates.” This clearly states that simultaneous disconnection is required. 240.15(B) focuses on overcurrent protection and gives you the choice of using single-pole circuit breakers with or without identified handle ties or multi-pole circuit breakers.
Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at firstname.lastname@example.org.