DM2-Inc
Senior Member
- Location
- Houston, Texas
In the closed thread Terminal Block in Non-Hazardous Enclosure Located in Class 1, Div 2 Location, BPoindexter provided a follow up questions concerning resistors in hazardous locations.
Robert B. Alexander responded with a reference
While the thread addressed issues related to Division 2 locations, 501.105(A), which addresses Division 1 locations, states:
I take this to mean that for Class I, Division 1, locations, the resistor must be in an enclosure rated for Division 1 locations (agreed and understood).
I've had a long standing debate over the qualifications of that resistor. One of our suppliers insists that we can't install this resistor, and that it has to be installed at the factory, which adds a significant lead time to the equipment for a single resistor (not to mention cost). I've been trying to find language in the NEC which states "...installed at the factory..." or something similar but haven't found it.
Considering the language in 501.105(A), and it's absence to requiring this to be installed at the factory, I'm of the opinion that the code doesn't prohibit me from installing the resistor at all.
Am I interpreting this correctly?
Robert B. Alexander responded with a reference
The basic concepts for applications of heat producing items in Division 2 are found in 501.105(B)(2) Exception:
While the thread addressed issues related to Division 2 locations, 501.105(A), which addresses Division 1 locations, states:
Class I, Division 1. In Class I, Division 1 locations, meters, instruments, and relays, including kilowatt-hour meters, instrument transformers, resistors, rectifiers, and thermionic tubes, shall be provided with enclosures identified for Class I, Division 1 locations. Enclosures for Class I, Division 1 locations include explosionproof enclosures and purged and pressurized enclosures.
I take this to mean that for Class I, Division 1, locations, the resistor must be in an enclosure rated for Division 1 locations (agreed and understood).
I've had a long standing debate over the qualifications of that resistor. One of our suppliers insists that we can't install this resistor, and that it has to be installed at the factory, which adds a significant lead time to the equipment for a single resistor (not to mention cost). I've been trying to find language in the NEC which states "...installed at the factory..." or something similar but haven't found it.
Considering the language in 501.105(A), and it's absence to requiring this to be installed at the factory, I'm of the opinion that the code doesn't prohibit me from installing the resistor at all.
Am I interpreting this correctly?