?
Friday, December 19, 2014
Question:
Charlie,
If a product that is UL listed does not meet the local code, is it mandatory to bring that product up to the local code?
Example: a group of VAV boxes came out to a job that had a Chicago plenum ceiling. The code does not allow greenfield (Metallic Flexible Conduit) in plenum ceilings. It does however allow for Sealtite or Liquidtite in plenum ceilings.
The VAV box came UL listed from the factory with a piece of greenfield on it. Do we void the UL listing if we change the greenfield to sealtite to satisfy the local code?? Or does the UL listing supersede the AHJ?
We had a similar incident where a Chiller came out to the jobsite with greenfield on it and the inspector noted that greenfield was not acceptable for use in an area where it could get wet. (The chillers were on the roof of a building. The greenfield was below the chiller but still exposed to the elements.)
Same question, Do you void the UL listing if you change the greenfield to Sealtite??
Norman Dong
A
Answer:
Hey Norman thanks for your question. Flexible metal conduit (FMC) is allowed in ceiling spaces used as plenums as stated in 300.22(C). For the 2008 NEC 348.12(1) was changed to not allow it to be used in a wet location. Previously FMC was permitted in wet locations if the conductors were suitable and the installation was made such that liquids were not likely to enter the enclosure.
I can think of several possible reasons why the equipment appears to not comply with the NEC regarding the FMC in a wet location. (1) It could have evaluated prior to the NEC change. (2) The laboratory evaluation determined that where the FMC was located it was not in a wet location. (3) Someone made a mistake. If a listed product is modified it doesn't literally void the listing. The product still appears in the evaluating laboratories list but it is different from what was evaluated. But you would probably void the manufacturer's warranty. I suggest you contact the equipment manufacturer then then possibly the laboratory that listed the equipment. It is up to the AHJ to determine compliance with the NEC as stated in 90.4 so a discussion with them should also take place.