Article 352 Ridgid Nonmetalic Conduit:Type RNC

[Mr. M]

A student in our electrical class asked when RNC was introduced to our trade.
Please advice.

Thanks,
Mr. M

 

[rcarroll]

I'm not exactly sure, but I think the 1999 code changed some of what we used to know. PVC became RNC, GRC became RMC, light fixtures became luminaires and so on.

 

[dhais]

This is an interesting read
http://www.carlon.com/aboutus.html

 

[mdshunk]

I think that fiberous asphalt stuff was around in the 40's. I forget what that stuff was called.

 

[infinity]

I think that fiberous asphalt stuff was around in the 40's. I forget what that stuff was called.

Around here it was called Orangeburg pipe.

 

[infinity]

Here's a link:

http://www.sewerhistory.org/grfx/components/pipe-orng1.htm

 

[mdshunk]

Around here it was called Orangeburg pipe.

Yeah, that's what I was thinking about. I just ran across this:

"For many years, especially between the years of 1930 and 1960, and to some extent in the 1970's, a special type of conduit has been used to house underground electrical power cables. This special conduit is a fibrous duct made of wooden pulp impregnated with coal tar. The two most common interior diameters with which the ducts have been created are 4 inches interior diameter and 5 inches interior diameter. Over the years many such conduits have deteriorated and blisters have been built up in many of the underground ducts."

 

[don_resqcapt19]

There was also something called "transite" (sp?) and that product contained asbestoses.
Don

 

[mdshunk]

There was also something called "transite" (sp?) and that product contained asbestoses.
Don

Did they use that for conduit? I see old Transite pipe used for furnace flues quite often.

 

[tom baker]

RNC no longer exists in the 2008 NEC.

 

[tom baker]

There was also something called "transite" (sp?) and that product contained asbestoses.
Don

It was used a lot for water mains. Water crews have special training on how to repair it. Its not a health hazard for water, but only if you breath the fibers.

 

[tom baker]

When PVC first came into the NEC, its used was restricted due to concerns with fire and smoke production. A proposal from Carlon for the 1980 (?) NEC was met with stiff opposition from the steel tube industry. STI=PVC is a fire hazard. PVC+ if you don't let us use it, we will sue for restraint of trade. It was not voted in, and was appealed all the way to the supreme court. As a result.the way code changes are appealed was changed. Now we use PVC nearly every where.

 

[don_resqcapt19]

Marc,
Yes, it was used for underground raceways, at least in this area.
Don

 

[don_resqcapt19]

Tom,

It was not voted in, and was appealed all the way to the supreme court.

Are you sure? I thought the only one that went to the courts was the ENT article where one or more of the metal conduit manufacturers "stacked" the meeting when that article was voted on. They paid for the NFPA membership and sent their people to the meeting to vote that article down. It delayed the entry of ENT into the code for a full code cycle. It is also the reason why you have to be a NFPA member for at least 6 months before you can vote on code changes at the NFPA meetings.
Don