A client has a building with a Class I Div 2 Group C, D area on the 1st floor with an open conduit/pipe chase to a 2nd floor that is Class I Div 2 Group B, C, D. I was expecting to see seal offs at the boundary where Group B was added, but there are no seal offs. There are seal offs at the boundary of the unclassified area and the Class I Div 2 Group C, D area. The building is well ventilated. The installation is about 25 years old. NEC 501 requirement for a seal off at a boundary seems to be exclusive to the Division there is no mention of groups or a change in groups constituting a "new" boundary. Is that a correct interpretation?
Class I Div 2 Group C, D and Class I Div 2 Group B, C, D
- Thread starter VaHoward
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Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
That is correct in regards to there being no new boundary between groups.
- Location
- Illinois
- Occupation
- retired electrician
Just be careful with the equipment selection in the Group B area...a lot of the commonly used equipment is only marked for use in Group C and D areas.
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