When was NM use in conduit FIRST enforced by the NEC?

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trecke

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Happy Thanksgiving to you all. I appreciate you taking the time to read my post. I am a residential building inspector and have been writing up NM in conduit for a while now and just received some push back from an unhappy home seller who lost a deal to my report. Basically here is the scenario - 1999 build house with basement that was finished by the homeowner in 1999 as well. Basement NOT done with permit OR licensed electrician. Many defects found (open splices, junction boxes without covers, loose runs of wire not secured within 12" of the termination, etc.) and the one issue they raised with me is how NM was allowed in conduit under the 1999 NEC.

For clarity, I understand NM in conduit to be an issue under three specific chapters:
334.12(B)(4) and 300.5(B) and 300.9 - I understand the issue to be a conduit "system" is a piece of conduit >/= 18" in length, a nipple is <17" in length - correct? So, any conduit system is by default a "wet location" which prohibits the use of NM. Even indoors correct? When was NM wire prohibited from use inside conduit? Thank you for your help!​
 
As MK stated in dry locations NM cable is permitted in conduit or tubing, in wet locations, such as anywhere outdoors or slabs in contact with the earth, it is not permitted. A nipple is defined as a piece of conduit or tubing 24" or less in length in chapter 9.

Welcome to the Forum. :)
 
ptonsparky said:
I don't understand why "any"conduit system would be considered wet. If that is true every setscrew fitting has been illegal.
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In Florida it's called condensation. It is wet. Underground conduit systems have water in them. Humidity causes water also.
 
ptonsparky said:
I don't understand why "any"conduit system would be considered wet. If that is true every setscrew fitting has been illegal.
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If it's exposed to water then water gets in. There are steps you can take to delay it, but it's very difficult to stop. A lot easier to just acknowledge it as a wet location and arrange to drain.
 
Welcome to the forum.
trecke said:
..... Basement NOT done with permit OR licensed electrician. Many defects found (open splices, junction boxes without covers, loose runs of wire not secured within 12" of the termination, etc.) and the one issue they raised with me is how NM was allowed in conduit under the 1999 NEC.
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These are all legitimate code violations

... So, any conduit system is by default a "wet location" which prohibits the use of NM. Even indoors correct?
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No. Not correct.
When was NM wire prohibited from use inside conduit? Thank you for your help.
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NM has never been allowed to be installed outdoors or underground. Some language was added in 2005 or 2008 to clarify that the inside of a conduit, when installed in a wet location, is also a wet location.
 
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