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  1. #1
    Roger Kautz's Avatar
    Roger Kautz Guest

    Default Mobile Home Service

    I do not see too many mobile homes, so I am happy to learn. This was a home in place for about 35 years in an established trailer park. The service came to a meter and panel on a pole just outside. The panel had a few breakers in it - I think from about 40 amp to 100. There was no way to remove the cover from this panel without disconnecting the power cords, and I had already decided to refer this to an electrician, so I did not explore this further. From there to the sub panel in the mobile home were two cords. All the other trailers in the vicinity had just one cord. Inside the interior Fed Pacific sub panel, the two cords ran their individual wires to common terminals ( ie, the two reds to one terminal, the two neutrals to the neutral bar, etc). There did not seem to be anything about this trailer to suspect that its electrical needs would be any different than any other. Why would there be duplicate power cords? What purpose is served by so many breakers in the outside panel when there are only 2 power cords -plus a 120 outlet that ran somewhere under the skirting.? (Yes, I gave the standard warning about the FP panel, and recommended an electrician for other stuff.)

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  2. #2
    Fred Warner's Avatar
    Fred Warner Guest

    Default Re: Mobile Home Service

    This looks like a disaster waiting to happen. My first observation is paralleled feeders. The "electrician" who ran these feeder cords in parallel presumably did so with an intention to increase the available ampacity from 50 amperes per cord set (looks like 2 125/250 volt 3-pole, 4-wire feeder assemblies) to an overall ampacity of 100 amperes for the remote panelboard in the mobile home.
    Take a look at 310.4 in the NEC. These conductors are smaller than 1/0. Notice that the ampacity of each individual paralleled conductor must be sufficient to carry the entire load if one or more of the other conductors (in parallel) becomes inadvertently disconnected. That is surely not the case in this installation.
    There are numerous other violations observable, but I'll let other forum members chime in.


  3. #3
    Dennis Webber's Avatar
    Dennis Webber Guest

    Default Re: Mobile Home Service

    Quote Originally Posted by Roger Kautz View Post
    There did not seem to be anything about this trailer to suspect that its electrical needs would be any different than any other. Why would there be duplicate power cords?
    Some parks (older ones) do not have 100 service avaliable. The only way to get it is to run two cords.

    What purpose is served by so many breakers in the outside panel when there are only 2 power cords -plus a 120 outlet that ran somewhere under the skirting.?
    My guess is they wanted to run air conditioning or some other heavy load (which may have disappeared before you had inspected it.)
    The receptacle under the home is required for a heat tape to be plugged into. It should be located near the water distribution inlet.

    I loved the use of duct tape to support the cords and branch ciucuit cable. Sort of capped off the installation.


  4. #4
    John Steinke's Avatar
    John Steinke Guest

    Default Re: Mobile Home Service

    It appears that the pedestal is arranged with a 2-pole breaker as the main disconnect, with branch circuit breakers to the side.

    Each receptacle would have it's own breaker. This would mean just one 'extra' breaker, and that would be for a light.

    Now .... pedestals tyoically will be supplied with a very, very modest amount of power ... 30 amps is common. The two 240v plugs usually have different plug patterns, to accomodate different cords. Hook up both, and you're still limited to what is supplied to the pedestal.

    Now, that particular trailer has had enough 'improvements' made to it, and enough blatant violations, that you really cannot make any comments without digging deeply into everything.

    For example, I would not even assume that there is 240v available!

    Another caution: DO NOT open any device boxes. Trailers of that age typically have aluminum wiring, with undersized grounds crimped together. Pull a receptacle out, and the ground will often break off at the crimp - making it almost impossible to repair.


  5. #5
    Dennis Webber's Avatar
    Dennis Webber Guest

    Default Re: Mobile Home Service

    Quote Originally Posted by John Steinke View Post
    Now .... pedestals tyoically will be supplied with a very, very modest amount of power ... 30 amps is common. The two 240v plugs usually have different plug patterns, to accomodate different cords. Hook up both, and you're still limited to what is supplied to the pedestal.
    John, the minimum power supply for a mobile home has always been 40 or 50 amps @ 240 volts (both under the old ANSI 119.1 or under the current HUD standards). (FWIW I never once seen a home with a 40 amp supply cord.)

    For example, I would not even assume that there is 240v available!
    It's has to be a 50 amp/240v supply cord and receptacle (unless this is a travel trailer. Only rec vee's are allowed to use a 30 amp pigtail.)

    Actually it was permitted to install up to three 50 amp power supply cords in mobile homes under NFPA 501B. It had to be acceptable to the AHJ (more often the park owner as they were the ones who had to pay for the supply pedestal and addl wiring.)

    Another caution: DO NOT open any device boxes. Trailers of that age typically have aluminum wiring, with undersized grounds crimped together. Pull a receptacle out, and the ground will often break off at the crimp - making it almost impossible to repair.
    I'm going to disagree as that's a too-broad-reaching statement to use. Most mobs did NOT use straight aluminum, and when they did use it, it was for only a couple of years. It's simply wrong to state that all older mobile homes are wired with aluminum wiring. For reference, many homes were also wired with aluminum during the years it was permitted. You would not want to state that any older site-built home was wired with alum just because of age; would you? And, I think you'll find that far more site-built homes burned than mobs. (Of course, far more site-built homes were built than mobs :-)

    FWIT, I worked as an in-plant inspector for UL back in the 70's when this wiring was popular. In addition to all the product categories of products produced in our Inspection Center area, I also inspected mobile homes on the production line for several different manufacturers. (Back then we inspected to the UL Procedure manual which was based on NFPA 501B-ANSI A119.1 Standard).

    I remember seeing some alum wiring used, cleaning the connections, dipping in an anti-oxidation solution; but every manufacturer I was inspecting quickly switched to CU/AL as AL was too much trouble on the production line (broke too often causing a lot of troubleshooting and repair). Some manufacture's never used straight aluminum, just CU-AL.

    In any case, I felt your statement may have been too far reaching. We would have to know the actual date the home was constructed to be more precise.

    Your right as rain however about it being dangerous, as this stuff did cause a lot of fires.


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