240V Line

Discussion in 'Amateur Radio Amplifiers' started by K4LD, May 22, 2012.

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  1. W1QJ

    W1QJ Ham Member QRZ Page

    I assume the panel is mounted on the surface of the house in a breaker panel listed for outdoor use. Then the wires enetr the panel from behind from a protected area. That is fine.
     
  2. K8MHZ

    K8MHZ Ham Member QRZ Page

    Romex is a brand name.

    NM, NMB and NMS would not be allowed. NMC would be acceptable if they came directly into the panel. Many cables are rated for multi-use. Even inside conduit, outdoor locations are considered wet, so NMC would not be allowed outdoors in conduit.

    Inside the panel would be a damp location to me. Outside the panel would be a wet location.

    THHW or THWN would also be acceptable even inside conduit run outdoors.
     
  3. AC0H

    AC0H Ham Member QRZ Page

    Exothermic welding is NOT brazing.
    It is a weld and part of the welding process is to form an alloy of the base metal and weld metal.
    A properly excuted weld will NOT come apart if reheated.
    Brazing is closer to soldering where a filler metal is melted to join two close fitting parts by capillary action.
    The only difference between brazing and soldering is the melting temp of the filler metal compared to solder.
    If you heat a brazed joint to melting temp of the filler metal it will come apart.
     
  4. K8MHZ

    K8MHZ Ham Member QRZ Page

    As I stated, only for cable rated for damp locations. NM and NMS are not.

    See the 2008 NEC, 334.12 (B). It states that NM and NMS shall not be used in wet or damp locations.
     
  5. W1QJ

    W1QJ Ham Member QRZ Page

    Outdoor fixture boxes are fed with NM (Romex) all the time for exterior lumaniers. Once you strip the outer shiething off the cable the inner wire contained in a rated exterior housing is just fine. Outdoor bell boxes mounted on the surface of buildinga are always fed with NM Romex from behind with no problem. How else would you feed an exterior bell box with a wire?
     
  6. K8MHZ

    K8MHZ Ham Member QRZ Page

    This is one of those code things that drive inspectors nuts. You are indeed correct, it does happen all the time. And, I have never seen it to be a problem. BUT, technically, the conductors would have to be for a damp location to be legal.

    Look at those luminairs. They all say 'must be connected to 90C conductors'. There was no such thing as 90C non-metallic sheathed cable, so the inspectors just allowed it. Now we have NMB, which is rated for 90C terminations.

    Do you have a code book? Take a look at 310.8(B). It reads, 'Insulated conductors and cables used in dry and damp locations shall be types'...and then the list about 20 types. Non-metallic sheathed cable is NOT there, so technically it isn't even allowed by the NEC, according to 310.8(B). Yet, it has its own chapter and one type is even allowed in damp locations.

    Luckily, there is also a passage in the NEC that allows the AHJ's (inspectors) to interpret the code as they see fit.

    Take a look at the marking requirements of receptacles sometimes. If a two prong receptacle is protected by a GFCI, that fact must be indicated on the receptacle. Not the cover, not the faceplate, not the wall near the receptacle, the receptacle. In order to fit, either the writing would have to be so small you couldn't read it, or on the back of the receptacle where you couldn't read it.

    I brought up the NM thing coming into the back of an outside box once to an inspector. (We were doing the work). He grinned and said that I was correct and he would happily fail me for it if I wanted. That was on a residential job. On commercial / industrial we use pipe and THHN/THWN so we actually do comply.
     
  7. W1QJ

    W1QJ Ham Member QRZ Page

    Mark, we are getting far off the topic here. As electricians we all know what we can get away with and where. We get to know the inspectors and those who except what. In my early days while going to school and working I would call things out to my boss, he'd get mad and simply say "everybody does it". SO it seemed if everybody does it, it must be OK. For example, alot of guys strip sheathing off cable like NM or BX and use it in conduit for a short run. You see this all the time, inspectors generally allow it, but it is wrong. Not really a hazard of any kind AT ALL but not code. Time to hash out something else.
     
  8. K8MHZ

    K8MHZ Ham Member QRZ Page

    I know one inspector that wouldn't allow it. He's also an Extra.

    And what is the 'BX' you speak of?? I don't see that as an accepted Chapter 3 cable. ;)
     
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