Boundary seals and Heat Trace cable

[KentAT]

How are boundary seals accomplished when Class 1 Div 1 heat trace cable is brought into a Div 1 building? The heat trace we use has specific instructions on stripping and separating as it goes through a seal to be terminated at the thermostat or heater.

Is it necessary to also do the same as the trace goes across a Div 1/Div 2 boundary, such as through the exterior wall of a Div 1 building?

 

[rbalex]

How are boundary seals accomplished when Class 1 Div 1 heat trace cable is brought into a Div 1 building? The heat trace we use has specific instructions on stripping and separating as it goes through a seal to be terminated at the thermostat or heater.

Is it necessary to also do the same as the trace goes across a Div 1/Div 2 boundary, such as through the exterior wall of a Div 1 building?

Yes. Note that 501.15(D)(2) [Class I, Division 1 boundary seals for cables that need boundary seals] makes no distinction between Division 2 and unclassified locations with respect to sealing in the Division 1 location.

There is a similar concept in 501.15(A)(4) [Class I, Division 1 boundary seals] that makes no distinction between Division 2 and unclassified with respect to “… each conduit run leaving a Class I, Division 1 location.”

Since the manufacturer has given instuctions - use them.

 

[BPoindexter]

Kent,

If the cable, in this case heat trace, is considered capable of transmitting vapors/gas and thus requires a seal you do not have to break the cable to seal it an the area transition. Just seal it at the termination point. Because the cable leaves the C1D1 area unbroken the termination seal serves as the boundary seal. Same as with MC-HL.