2 Pipes, 1 Feeder

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A-1Sparky

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There's a new MCC that I was working in recently, and I noticed that the contractor that installed it had run (2) 2" conduits into the MCC from an overhead trough. One conduit had A Phase and B Phase in it, and the other conduit had C Phase, a neutral, and a ground in it. I'm pretty sure this is a violation, but I'm not sure exactly where to look in the code book to verify this. Can anybody point me in the right direction? Thanks in advance.
 
Thanks for the quick reply! Just wondering if there are any safety issues (inductive heating, etc.) with this install. I just need to know if I should make the contractor come back and rectify the problem.
 
A-1Sparky said:
Thanks for the quick reply! Just wondering if there are any safety issues (inductive heating, etc.) with this install. I just need to know if I should make the contractor come back and rectify the problem.
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They shouldn't walk, they should run back and fix the problem.
 
A-1Sparky said:
Thanks for the quick reply! Just wondering if there are any safety issues (inductive heating, etc.) with this install. I just need to know if I should make the contractor come back and rectify the problem.
Click to expand...
Look at 300.20 for that info.
 
Maybe the owner of the MCC should be informed just in case the contractor ignores the problem or "forgets" to make the correction. If that happens, you could wind up getting paid to fix it.
 
Is the conduit ferrous? Is there ferrous metal between the conduit entries at the MCC? If so there is a serious heating issue if there is much load on the feeder. If not there may not even be a code violation.
 
The conduit from the trough to the MCC is EMT and the material between conduit entries is ferrous (painted steel). I'm not sure of the exact composition of EMT, but I would say that it's definitely ferrous (as well as the fittings and locknuts). As far as load goes, I haven't taken any readings yet, but would guess that it's around 100-150 amps at any give time.
 
Yes the EMT is ferrous. Has this circuit been energized yet? If you have 150 amps of load, I would expect that the conduits are getting warm if not hot.
 
Yes, the MCC is energized. I'm not sure if the EMT is warm or hot, as I haven't checked that yet. I plan on taking some load readings on Monday morning, so I'll check the conduits for heat then. Thanks for all the info.




Matt
 
Please let us know about the load and any heating. This is a much discussed violation, but one I rarely see and I would like to hear the feed-back on a "real-life" install.
 
Well, I got some load readings this morning and I checked the conduits for heat. At the time, there was only about a 45 amp load on the MCC and the pipes were not abnormally warm. I'm wondering if that would change with a more significant amperage. Nonetheless, I contacted the site rep. who okayed the install and provided him copies of the NEC pages that explain the violations. The ball's in his court now. :cool:
 
150 amps may not be enough load to produce a lot of heat. The Canadian Electrical code does not see this as an issue for loads under 200 amps.
 
Yeah, I read the article Gus recommended on that, and it said pretty much the same thing. I'm still going to follow up on the situation and make sure the contractor fixes the problem. I took a look at the specs yesterday, and the engineer had called for (1) 2.5" conduit instead of the (2) 2"s that were run. So, per contract, the EC has to remedy this anyway. I think he's still waiting on final payment anyway. ;)
 
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