wroggent
Electrical
- Aug 20, 2012
- 288
I have been brought into a project to install an already purchased and delivered air compressor from a well known maker of air compressors and I am struggling with two issues:
(1) The SCCR value given on the nameplate within the electrical enclosure compartment in the compressor package is too low for the application.
The manufacturer's suggested solution to this is to provide a fused disconnect (safety switch) that we would install ahead of the enclosure 'at' the compressor.
Questions:
If the equipment were to be UL listed, to what standard would the equipment be listed to? 508A?
Is it possible to apply a separately mounted fused disconnect (with manufacturer recommended/required fuses) and raise the SCCR and fully meet the requirements of the applicable UL standard? (I would think any protective device used that affects the SCCR would need to be located inside the enclosure)
In spite of the answer to question 2 possibly being no, would you accept the solution?
Note: I did not see any labeling to indicate that the unit is UL listed nor have I asked the manufacturer if it is yet. I would feel more amenable to the solution if the unit was UL listed and they provided a new label/nameplate as I feel they would carry (more/enough?) liability in this case.
(2) On the same nameplate mentioned before, there is a section that says "Control Enclosure....UL Type 1" which I've interpreted to mean that the environmental rating of the enclosure is what I would call 'NEMA 1'. This compressor will be installed outdoors and even includes an 'low ambient option' package for this purpose.
Mounted through a hole on the front of the enclosure is a PLC/controller for the compressor. On the backside of this PLC/controller there is a label with a section that says "Environmental Rating: UL Enclosure Type 1 (only for front face)." The backside of the PLC/controller has what I would call not finger safe terminations, and the front is just buttons and a display. The electrical enclosure overall looks similar to what I would expect of a NEMA 4 rated cabinet, which is what the intended/required rating is. My belief is that the PLC/controller is not intended for outdoor use and is the source of the "UL Type 1" rating for the enclosure. In talking to the vendor about this their response was (1) the hole for the PLC/controller has a gasket and (2) they provide NEMA 4 cabinets for outdoor units and I have an outdoor unit therefore it must be NEMA 4.
Questions:
Do you think I have just not talked to the right person or would you accept their response?
Other information:
Country: United States
Permitting: None
AHJ: none/unknown
Code: NEC (at will)
Location: Power Plant
(1) The SCCR value given on the nameplate within the electrical enclosure compartment in the compressor package is too low for the application.
The manufacturer's suggested solution to this is to provide a fused disconnect (safety switch) that we would install ahead of the enclosure 'at' the compressor.
Questions:
If the equipment were to be UL listed, to what standard would the equipment be listed to? 508A?
Is it possible to apply a separately mounted fused disconnect (with manufacturer recommended/required fuses) and raise the SCCR and fully meet the requirements of the applicable UL standard? (I would think any protective device used that affects the SCCR would need to be located inside the enclosure)
In spite of the answer to question 2 possibly being no, would you accept the solution?
Note: I did not see any labeling to indicate that the unit is UL listed nor have I asked the manufacturer if it is yet. I would feel more amenable to the solution if the unit was UL listed and they provided a new label/nameplate as I feel they would carry (more/enough?) liability in this case.
(2) On the same nameplate mentioned before, there is a section that says "Control Enclosure....UL Type 1" which I've interpreted to mean that the environmental rating of the enclosure is what I would call 'NEMA 1'. This compressor will be installed outdoors and even includes an 'low ambient option' package for this purpose.
Mounted through a hole on the front of the enclosure is a PLC/controller for the compressor. On the backside of this PLC/controller there is a label with a section that says "Environmental Rating: UL Enclosure Type 1 (only for front face)." The backside of the PLC/controller has what I would call not finger safe terminations, and the front is just buttons and a display. The electrical enclosure overall looks similar to what I would expect of a NEMA 4 rated cabinet, which is what the intended/required rating is. My belief is that the PLC/controller is not intended for outdoor use and is the source of the "UL Type 1" rating for the enclosure. In talking to the vendor about this their response was (1) the hole for the PLC/controller has a gasket and (2) they provide NEMA 4 cabinets for outdoor units and I have an outdoor unit therefore it must be NEMA 4.
Questions:
Do you think I have just not talked to the right person or would you accept their response?
Other information:
Country: United States
Permitting: None
AHJ: none/unknown
Code: NEC (at will)
Location: Power Plant