Article 427.55 Heat Trace Disconnecting Means

[Steve Merrick]

I work in Alaska and we use a lot of heat trace up here. NEC 427.55(A) states the heat trace branch circuit breaker, where readily accessible, shall be permitted to be used as the circuit disconnecting means. It also requires, "The disconnecting means... shall be provided with a positive lockout in the "off" position."

A group of our electrical inspectors just came back from a Code class and they are now insisting that branch circuit breakers may *NOT* be used as disconnecting means for heat trace circuits unless the breakers are permanently fitted with the padlock receivers. In other words, standard lockable branch circuit breakers covers are no longer being allowed as lock-out devices for heat trace circuits, when 427.55(A) specifically states they "shall be permitted."

I don't see how a heat trace circuit is different from any other branch circuit disconnecting and energy isolation means. What do you think?

Thanks!
Steve

 

[Gregg Harris]

I work in Alaska and we use a lot of heat trace up here. NEC 427.55(A) states the heat trace branch circuit breaker, where readily accessible, shall be permitted to be used as the circuit disconnecting means. It also requires, "The disconnecting means... shall be provided with a positive lockout in the "off" position."

A group of our electrical inspectors just came back from a Code class and they are now insisting that branch circuit breakers may *NOT* be used as disconnecting means for heat trace circuits unless the breakers are permanently fitted with the padlock receivers. In other words, standard lockable branch circuit breakers covers are no longer being allowed as lock-out devices for heat trace circuits, when 427.55(A) specifically states they "shall be permitted."

I don't see how a heat trace circuit is different from any other branch circuit disconnecting and energy isolation means. What do you think?

Thanks!
Steve

Chapter 4 Equipment for General Use :: ARTICLE 427 Fixed Electric Heating Equipment for Pipelines and Vessels :: VII. Control and Protection

427.55 Disconnecting Means.



(A) Switch or Circuit Breaker. Means shall be provided to simultaneously disconnect all fixed electric pipeline or vessel heating equipment from all ungrounded conductors. The branch-circuit switch or circuit breaker, where readily accessible to the user of the equipment, shall be permitted to serve as the disconnecting means. The disconnecting means shall be of the indicating type and shall be provided with a positive lockout in the ?off? position.
Are you sure you are understanding what they are asking?

The lockable means must be permanently installed, and not a portable LOTO mechanism.


2014
110.25 will require this

 

[Steve Merrick]

110.25

110.25

Thanks - I forgot about 110.25. That makes the requirement pretty clear. It just seems strange that we are not allowed to supply a short length of 120 volt self-regulating heat trace from a standard distribution panel EPD breaker. Why should heat trace have different lockout requirements from any other load? Oh well - it is what it is.

Thanks again,
Steve