410.31 Luminaires (fixtures) as Raceways

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bilwei

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Lufkin, Texas
Intro Info; The owner of a new building has hired me as a 3rd party to look into the electrical system after the owner encountered burned wiring resulting in numerous electrical issues. I will only ask an opinion on one of these issues at this time. I have a building with 2 X 4 lay in troffer fixtures thru out. The electrical contractor that wired the building has installed MC cable (switch leg only)from fixture to fixture and made joints in each fixture. The AHJ has issued a final green tag & Certificate of Occupancy. I asked the AHJ about this particluar installation and refered him to Section 410.31. AHJ response; contractor did not use the fixtures as a raceway. Since there is only a joint made up in the fixture and they are are only dealing with a switch leg and not feeding a branch circuit thru to other electrical apparatus therefore it is not a code violation. What say yee
 
IMHO, MC cable is just that. It is a cable, not a raceway. See article 100 for raceway.
I think the inspector is correct.
 
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I agree with the inspectors call (and xformer)
also,.. minor point, but... if I understand correctly, we have a branch circuit (switched or unswitched) feeding fixture one with MC, connected to a 2nd MC to fixture 2, etc.
If that is the case, I don't think the term "switch leg" is correct
 
Good point. Next item; the MC cable is supported on the ceiling grid wire hangars( at various unknown lengths) with bat wings. That seems to me to be a violation of 300.11. I did not see the MC cable strapped within 12" of the connection point to the fixture.That seems to be a voilation of section 330.30 (B).

They also installed a twin MC connector to allow them to install a 3rd connection to feed another fixture. Some of the electrical problems are caused by the poor joints in the fixtures. They cut the wire to short too allow them to fold neatly into the ballast housing with the wire nut on them. They crammed them in the ballast housing. The belly pan is spring loaded. I guess that is just poor workmanship.
 
bilwei said:
Good point. Next item; the MC cable is supported on the ceiling grid wire hangars( at various unknown lengths) with bat wings. That seems to me to be a violation of 300.11..
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Possibly, but see this thread:
http://forums.mikeholt.com/showthread.php/135264-Lay-in-2x4-support-wires
bilwei said:
I did not see the MC cable strapped within 12" of the connection point to the fixture.That seems to be a voilation of section 330.30 (B). .
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Be sure to check 330.30(D) also
bilwei said:
They also installed a twin MC connector to allow them to install a 3rd connection to feed another fixture. Some of the electrical problems are caused by the poor joints in the fixtures. They cut the wire to short too allow them to fold neatly into the ballast housing with the wire nut on them. They crammed them in the ballast housing. The belly pan is spring loaded. I guess that is just poor workmanship.
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330.30 (D) Interesting point. Do you think that 330.30 (d) applies to a lay in ceiling? This is a new building. It wasn't necessay to fish through the area. Do you think that the AHJ would interprete the installation that way? That would be a twist.

Also, they did not support the fixtures with an independent wire from the structure. As a matter of fact they did not even use the tabs on the fixture to clamp the fixture to the grid nor did they use any other fastening method to attach or support the fixtures.

Further Info - The building is a prefab metal building. The z-purlins are within 3' to 5' of the ceiling grid.
 
bilwei said:
330.30 (D) Interesting point. Do you think that 330.30 (d) applies to a lay in ceiling? This is a new building. It wasn't necessay to fish through the area. Do you think that the AHJ would interprete the installation that way? That would be a twist. .
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I think 330.30(D)(2) {'08} does as it states "accessible ceilings"
bilwei said:
Also, they did not support the fixtures with an independent wire from the structure. As a matter of fact they did not even use the tabs on the fixture to clamp the fixture to the grid nor did they use any other fastening method to attach or support the fixtures.

Further Info - The building is a prefab metal building. The z-purlins are within 3' to 5' of the ceiling grid.
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Wow, after studying the the section as you suggested, I agree with you. I can see how it would be interpreted that way. I would not ever allow my employees to do such sloppy work but thats not the point here. I just need to resolve the poor wire connection issues for the owner and move on. The EC that did the work is taking the NEC to the bare minimum standard that is allowed.

Thanks for the info. It helps tremendoulsy to get input from other people which makes me keep an open mind to interpretation of the NEC.
 
bilwei said:
Also, they did not support the fixtures with an independent wire from the structure. As a matter of fact they did not even use the tabs on the fixture to clamp the fixture to the grid nor did they use any other fastening method to attach or support the fixtures.
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410.36 B is where you will find supporting the lights. Here in MA we have to support with chain or tie wire on opposite diagonal corners to building structure
 
augie47 said:
I agree with the inspectors call (and xformer)
also,.. minor point, but... if I understand correctly, we have a branch circuit (switched or unswitched) feeding fixture one with MC, connected to a 2nd MC to fixture 2, etc.
If that is the case, I don't think the term "switch leg" is correct
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Your are correct. The 12/2 WG MC cable is continous from end to end. It starts from the switch box and continues between the fixtures until it reaches the last fixture.
 
LarryFine said:
I wonder if they used fixture whips with 18ga wires instead of MC with full-sized conductors.
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The EC used 12/2 WG MC cable from end to end. They started at the switch box and continued to the first fixture and then to the next fixture etc. until they reached the last fixture except when they would jump to another fixture not in line with the others. In other words, sometimes there would be Three MC cables connected to a fixture.
 
bilwei said:
The EC used 12/2 WG MC cable from end to end. They started at the switch box and continued to the first fixture and then to the next fixture etc. until they reached the last fixture except when they would jump to another fixture not in line with the others. In other words, sometimes there would be Three MC cables connected to a fixture.
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There is nothing wrong with this and it is very common.


This graphic shows AC cable the rules for MC are very similar.

1008708069_2.gif
 
Sorry I got off point from my task at hand. Let me explain. The owner had some on going issues with the project EC. The owners (building and electrical) inspector pointed out some electrical code violations during the building process. The owner presented them to the EC to correct. End of story right?? The AHJ had already issued the final Green tag and certificate of occuppancy and the owner has occuppied the building. They started experiencing sporatic electrical problems. They Called the EC. The EC said everthing was okay. Then they started smelling something that might be hot. So their maintenance man (licensed Journeyman Electrician) started looking into the problem and found some poor terminations. The owner elected to call me in as a 3rd party to check out the system. They had no confidence in the project EC for various reasons unkown to me. So here I am in a wasp nest. They asked me to give the building a once over to spot NEC violations while I was there looking at all the wire connections. I saw a few obvious violations and a few I wasn't so sure. The not so obvious are the ones (or not sure of) I brought to the forum.
 
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