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chass989 (Electrical) (OP)
26 May 10 17:48
My question is are you required to have seals on nema 4  boxs with terminal strip wiring, or rosemount transmitters 4-20ma wiring in a class 1 div. 2 area
Helpful Member!  resqcapt19 (Electrical)
27 May 10 7:37
There is no requirement for a seal on the NEMA 4 box that contains splices where the enclosure is in a Class !, Division 2 area.  Enclosure seals in those areas are only required if the enclosure is required to be of explosion proof construction.  501.15(B)(1) in the 2008 code.  

There is differing opinions on the question of the transmitter seal. Many apply the exception to 501.105(B)(2) to the transmitter and say that the transmitter enclosure is not required to be of explosion proof construction and therefore seals are not required in the division 2 area.

Others say that while the maximum normal operating temperature of the transmitter is very likely to be below 80% of the auto ignition temperature of gasses involved it is possible under conditions of transmitter malfunction that the temperature will exceed the 80% value and that seals are required.  

Most of the plants in my area take the first view on this and do not require seals for the transmitters.
chass989 (Electrical) (OP)
27 May 10 8:57
Thanks resqcapt19
One other question what about lighting fixtures rated class 1 div.2 I don,t recall ever seeing seals on lighting in past plants I worked in and this plant does not have seals on lighting also is this O.K.
Thanks
Chass989
resqcapt19 (Electrical)
27 May 10 18:29
In general, seals are not required for light fixtures.
JLSeagull (Electrical)
1 Jun 10 18:22
Arn't seals required between the division 2 and non-hazardous areas such as the home run cables from a junction box and feed from the MCC breaker to a classified lighting panel, etc.?
resqcapt19 (Electrical)
2 Jun 10 7:23
JL,
Yes, in general seals are required at the classification boundaries. I took the question as asking about seals at each light fixture in the classified area.    

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