Romex

[Barn Owl]

My conversion was done in 1979 and PO did it with "Romex" (NM for the 120v stuff, stranded for 12v). Thirty-one years later and it still looks good. The only thing I don't like is that it is hard to snake around in the tight RV spaces.

[brando4905]

FWIW, I wired a service pole for power down at my bus gravel pad, and had used Romex to the outlets. Inspector turned it down at first because of the paper in the Romex. Romex no longer passes electrical code in North Carolina. I removed the paper and called him back, passed. I guess the paper is now considered a fire hazard.

My bus is wired with Romex for the high voltage stuff.

[Len Silva]

The NEC is the basis for most state and local authorities but they may make the rules more strict if they wish.  Now, as for prohibiting type NM where it is otherwise accepted by the NEC seems a bit of overkill to me.

If you left the paper on the ground wire in the box or panel, that is generally not done.  I can't imagine why the inspector would not have allowed you to correct that on the spot, couldn't have taken more that a minute.  Do they charge more for a return trip?  That might explain it.

[chris4905]

I have only been involved in the bus conversion for about the past 12 years (very few years compaired to some of the fellas).

This sold vs. stranded wire issue was being "discussed" when I came aboard.  Don't know if it will EVER really be "settled".

We all have our freedom of choice to do it "our way", which of course is a good thing !!

Chris

[John316]

We all have our freedom of choice to do it "our way", which of course is a good thing !!

Chris

And your point is?

God bless,

John

[john9861]

Sean,
        I'm sure this subject has been serviced before but why not talk about it again. What is the do's & don'ts to using extension cord wires for your 120 AC like your lighting & plug outlet circuits? It is stranded. It is incased. It is rated for certain amperages based on the quality of cord you buy. They surely are made to take a bit of abuse. Sometimes you can catch them on a real good sale. Admittedly I haven't compared price per foot but anyway what ya think?
     

[Sean]

... I'm sure this subject has been serviced before but why not talk about it again. What is the do's & don'ts to using extension cord wires for your 120 AC like your lighting & plug outlet circuits?     

Extremely dangerous, and also illegal.  I discussed this in more depth here:
http://www.busconversions.com/bbs/index.php?topic=8102.msg80357#msg80357

I also wrote this, on "another board":

When you ask "why" extension cords are not to be used, I assume you are asking why the code (and the cord's manufacturer) prohibits this.

The simple answer is that extension cords are made for temporary use, not covered by or enclosed in any other material. Consequently, the cords are designed so that any heating of the conductors is transmitted through the insulating materials into free air, where the heat is dissipated.

By installing an extension cord within a wall, or even covering it with, say, a rug, you have changed the conditions away from those for which the cord was designed and rated. This can result in insulation melting, conductors shorting, paper fillers (yes, paper is found in some cords) to smolder or catch fire, and insulating materials to out-gas toxins.

I will also point out that once you cut the ends off an extension cord, it is no longer an extension cord. Now it's just cord, and it's allowable uses are determined by the type and rating of the cord itself. Many heavy-duty or "contractor grade" extension cords are made from type SJ cord, which is known as "junior hard service" cord. You are certainly free to use this anywhere type SJ is permitted.

Fixed wiring inside of walls, floors, and the like, even when enclosed in rated conduit, is not a permitted use of SJ cable. In fact, there are a limited number of types of cables and assemblies allowed for this use, such as types NM, AC, and MC cable, as well as a variety of thermoplastic wire enclosed in various conduits.

You can read that entire thread here:
http://www.busnut.com/bbs/messages/11/29229.html

I also discussed pontificated on the topic here:
http://www.busnut.com/bbs/messages/11/28863.html

-Sean
http://OurOdyssey.BlogSpot.com

[Lin]

The problem is that we who are uneducated in this science, tend to look at a wire and see wire.  We generally think we're pretty good because we know the differences in wire gauge.  Hence, since 12 extension cord looks and smells like other 12 gauge wire, we find it hard to accept that it is not equal.  Although I still have doubts, I feel most comfortable listening to someone who knows a lot more about this stuff than I.

My original question was not meant to start the same questions and debates we have seen before, but just to see if it mattered about using my old Romex stock for low voltage.  It seems that there is nothing inherently dangerous about that other than creating confusion about which runs are high and which are low voltage.  That seems significant enough for me.  That, and the realization that the Romex is really a 2+1 set up rather than 3 usable wires.  This increases the sloppiness of concept that much more.  Since it is low voltage, I would not feel bad about using extension cord.  Correct me if wrong, but there is no danger there, and since I will not use extension cord for 120 volts, there is little chance of confusion.  However, the only reason to use extension cord inside the condenser piping would be that it is cheap.  I have just spoken to a local electrical supply shop.  They sell stranded 12 gauge wire in assorted colors for 18cents/foot, so there is no real financial incentive to using extension cord for even low voltage.  I would however, consider using it in a less protected, dedicated run.

[john9861]

Thanks Sean,
                  I'm not far from the elctrical part of my conversion so this has been very helpful. Looking forward to doing things right.
John

[Sean]

...  Since it is low voltage, I would not feel bad about using extension cord.  Correct me if wrong, but there is no danger there, and since I will not use extension cord for 120 volts, there is little chance of confusion.  ...

"Automotive" circuits of less than 30 volts are not covered by the NEC, and therefore the code has nothing to say about what wire can or can not be used.  There are other standards, including those published by the SAE, for specific circuits dedicated to vehicle operation, and I can not speak authoritatively on those since I do not have a copy. 

RV house circuits under 30 volts generally are covered by ANSI/RVIA 12V, "Low Voltage Systems in Conversion and Recreational Vehicles."  I confess I do not have a copy of this standard and so I can not speak to whether type SJ cable (what most contractor-style cords are made from) in an appropriate gauge is or is not permitted for these circuits.  ANSI/RVIA 12V is incorporated by reference into NFPA 1192 and is therefore mandatory code in any state that has adopted 1192.  To the best of my knowledge, most wire and cable types found in the NEC are allowed, and that would include SJ.

Not that it's relevant here, but there are, in fact, low-voltage systems that are covered by the NEC and must use appropriately rated cables.  These include communications systems (covered in Chapter , as well as fire alarms, emergency systems, and other signaling applications (covered in Chapter 7).  I suppose one could make the case that if you were to install a telephone system in your bus, it would need to use the proper cable.

-Sean
http://OurOdyssey.BlogSpot.com

[kyle4501]

Doesn't the amp load heat the conductor - NOT the voltage?

So,
Amp load determines wire size.
Voltage & environment determine the insulation.

When insulation fails, a short circut is more likely.
All the more reason to use wire with the appropriate insulation. Things don't usually go well when the insulation fails.

[niles500]

Kyle it's more correctly the resistance that provides the "heat" - SJ cord (or equivalents) should NEVER be used in any "enclosed" environment - NO IFS ANDS OR BUTS - PERIOD! END OF STATEMENT!

Specifically loads such as coffee pots and electric heaters among others will push SJ, et.al to or above their design limits, and encasing them in any way would eliminate their ability to dissipate the heat generated by such a resistant load - Not any radical science here - Simple "magic" for all the disbelievers - here's the rules for the rest of you (no NEC for the code naysayers)

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=9882&p_table=STANDARDS