frenchie said:
Cubey, FYI? I'm not an electrician, but I know the guy you're argueing with. He teaches code for a living. If he says you're misunderstanding that section... you're probably misunderstanding that section. Chill out & ask him nicely, he might take the time to explain it to you, but get down off that high horse, first. Electricians with decades of experience go to him for help with code interpretation, or "where do I find the section that deals with ____". You do not know the code better than him.
I don't think you understand what "unless specifically permitted" means. In code speak, the key word here is "specifically". There would have to be something in 400.7 that said some kinds of wires could be run through dryer vents, and there isn't.
The interpretation you're using of 400.7, would make 400.8 completely redundant. If I can run an extension cord through a wall for any purpose that I'm allowed to use an extension cord in the first place, there would be no possible situation where I couldn't run a cord through a wall, except situation where I can't use a cord in the first place. Think about it. 400.8 would become meaningless.
I did ask nicely at first but never got a decent response.
Regarding "unless specifically permitted" the code actually doesn't say ANYTHING about any specific
kinds of openings in the wall in which you COULD run a flexible cable through. According to you and him that means you can never do it.
Yet the code pretty blatantly says that under certain circumstances such as with "utilization equipment to facilitate frequent interchange" which includes RVs you
can do it. 400.8 says that it's allowed depending on certain conditions outlined in 400.7. Pretty sure that, under any sort of logic, means that for RVs you can run a flexible cable through a wall of an RV or other "utilization equipment to facilitate frequent interchange". Plus the fact that they do it on new RVs made in the USA. They use a special hatch/storage place for the hookup on the RV, but..... the code never says that it has to be a special kind of opening. The special openings on RVs are there just because thats the optimal way to do it. In the case of what I'm doing, a dryer vent is the optimal way to do it. Both are plastic, weather proof openings that allow the flexible cable to enter the RV.
Unless the code contradicts itself that means you can run a flexible cable through the wall of an RV with any safe means needed. Weather proofing the hole in which it runs through is just plain common sense. If they added in every possible thing you must do for wiring, the NEC code would be a do-it-yourself guide to electrical wiring. They assume you know how properly and safely run the cable/wire you are installing so that you don't have water coming in the hole in which the cable is running.
Also, I found a site that lists all of the 2005 NEC codes. There is a section (B) of 400.7 not posted up to now in this thread that points out about section 6 of 400.7(A) that states attachment plugs placed on flexible cable is permitted for plugging into an outlet for power. That would mean you can have a flexible cable to plug into an outlet for power according to 400.7(A). 400.8 seems to state that if 400.7(A) 6 is met then running the cable through a wall is permitted according to 400.8.
Again, no where in 400.7 or 400.8 does it say any certain openings in the wall are allowed. 400.8 states that unless specifically permitted in section 400.7 it is not permitted to run a flexible cable through a wall. However, an RV falls under 400.7 sec 6 and therefore is permitted to have a flexible cable with a plug on it run through the wall. But it does not state that it needs any certain kind of opening in the wall anywhere in the code.
Check out the attached image for the 400.7(B) section. I got that from here:
http://www.nfpa.org/freecodes/free_access_agreement.asp?id=
The format in which the site presents the NEC codes via Java doesn't allow copy and paste so that is why I did a screen shot image instead.
frenchie said:
As a non-electrician who just happens to live in a northern climate, I'm going to point out the really obvious flaw in your plan: every electric heater I've ever seen, comes with a warning that you shouldn't use an extension cord with it. Oops! Time to switch to plan B.
There is no plan B except completely rewiring the trailer or getting a better gas heater. A gas heater is more likely doable than rewiring the trailer I think unless I could figure out an easy way to add in a 30amp inlet. However according to the people in this thread (mis?)quoting the NEC code, I could never do that even though that is how all modern RVs are. Now do you see why I'm getting annoyed in this thread? According to the folks in this thread, it's against NEC code to even do it the proper way since it would require flexible cable to run through the wall. Sorry, but I'm not the one who is wrong here on the subject of flexible cable running through the wall of an RV. The others in the thread have simply stated flat out its against the NEC code and that is incorrect.
I would have to say that the warning on heaters not to run it on an extension cord is due to the fact that most people would grab their light weight 2 wire household extension cord of about 16 gauge. The power cord on the heater I have is 14 gauge. If someone were to plug that into a 16 gauge cord and run it at 1500W, there is your fire hazard with using an extension cord right there. I plan(ned) on using a 25' 12 gauge extension cord so it will be able to carry the load of a 1500W heater without overloading it since the cord on the heater itself is 14 gauge.