Housing Splices

[Machiavelli999]

I just had one of those dinner moments. One where you are sitting there eating with your family and then you realize, uh oh.

Anyway, I am working for a cleanroom client. We are installing what are called fan filter units that sit recessed into a T-Bar ceiling and are there to basically make sure the air that comes into the room is filtered.

The units come with a pigtail to which the incoming power feed must be spliced to. My understanding is that all splices must be housed in junction boxes. However, the way we have these units mounted it is very hard to attach a junction box to them. The unit's manual says the following:

"Power wiring
Wire the 208-277VAC single-phase power into the junction box on
top of each FFU. This should be performed by a qualified
electrician with all appropriate safety measures."

So, my assumption was that the box on top of the unit from which the pigtail comes from can house the splice. It's a metal, grounded enclosure with a cover so the splice won't be exposed. However, this box is part of the unit. I don't know what the NEC considers an "approved junction box", but would this classify.

(If you are interested, this is how the units look like: http://www.cleanpak.com/ffu_semi.html)

 

[Machiavelli999]

Well, I just clicked on the unit's specification here: http://www.cleanpak.com/pdf/FFUCPID_Technical_Bulletin.pdf

It clearly states that "A junction box is provided on the top of unit for input power."

So, that makes me feel a little better.

 

[hurk27]

In looking at the PDF I would believe the SJO cord pigtail was just a testing cord that is to be disposed of and replace by permanent wiring to the junction box located on top of the unit, as the pigtail would be a violation of article 400 of the NEC as using flexible cord for permanent wiring, and or in a suspended ceiling, and it makes no sense to bring it back into the same junction box it is already connected to, not sure in how you connected it but it looks like the pigtail should have just been removed and permanent wiring installed right to the junction box?

Edited to add: the NEC has not allow cords above a suspended ceiling as far back as I can remember (at least the 1999 doesn't allow them) and I noticed that this manufacture looks like a German company who might not follow the NEC, so the pigtail is a violation, and like I said it might have been a testing cord used by the factory to do QC testing and is just left in place to be removed by the installer/electrician, this was also done on pool pumps who also left a straight blade 120 volt plug pigtail on the pump and was not allowed to be used as a twist Lock plug is required in 680, so this sounds similar, I would believe that the pigtail was intended to be removed and the proper wiring method used.

 

[jusme123]

Power wiring
Wire the 208-277VAC single-phase power into the junction box on
top of each FFU. This should be performed by a qualified
electrician with all appropriate safety measures. The input power
wiring into the junction box will be as follows:
black=hot
white=neutral for U.S. 277VAC 1~; red=hot for U.S. 208VAC 1~
green=ground.
The controller in each FFU is a universal voltage controller capable
of accepting:
277VAC single-phase with hot, neutral, and ground, or
208VAC single-phase with hot, hot, and ground.
Control wiring