Pellet Stove AC cord - Fixing, replacing and upgrading for more power?

Don2222 Posted By Don2222, Jun 29, 2018 at 9:00 PM

  1. Don2222

    Don2222
    Minister of Fire 2.
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    Feb 1, 2010
    8,187
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    Loc:
    Salem NH
    Hello
    Just working on a stove that may have been headed to the scrap heap because the AC plug was cut off! LOL
    See
    https://www.hearth.com/talk/threads/what-is-wrong-with-this-pellet-stove-see-video.168941/
    Has Anyone fixed their AC cord?

    One item I thought could be better is the strain relief! The special oblong hole cut in the sheet metal and squeezing the blunt end into trying to bite into the wires is a very old design!
    In fact it seems to be made for only 18 or probably 20 Guage. I tried to use it for 16 Guage but it bit into the wires so much it caused leakage from either the black Hot or white ground greater than 5 milliamperes and tripped the GFCI outlet on the wall in the house! Leakage at 75 milliamperes or greater to the ground wire can make the metal body of the stove hot and be a shock haszard!
    I found a newer designed strain relief at an electrical store that is also made for heavier Guage wiring like 16 Guage. :) This new design has a bunch of plastic fingers that clamp down on the jacket of the AC cord and applies even pressure all around the wire! This just makes much more sense and requires approximately 5/8” Mounting hole that can easily be made with a step drill bit from Harbor Freight. In fact the oblong hole for the original strain relief can easily be drilled larger using the step drill bit.

    Pic 1 - Cut AC cord
    A new plug could be attached but a new cord with a new molded plug is safer and wil not fall apart.
    Pic 2 - new Strain Relief
    Pic 3 - Drilling out larger hole
    Pic 4 - new strain relief installed with new 16 Guage 3 prong AC cord.
    Pic 5 - New insulated spade clips crimped on to new AC cord and plugged into pellet stove wiring harnes. Note the old ground wire came out of stove between the ventilation slats in the back panel and attached to a screw that held the back panel on. This makes it very cumbersome to remove the panel and service the pellet stove. In this case a new round clip crimped onto the green ground wire is now grounded to the body of the stove with a stainless steel self tapping screw seperate from the back panel,
    Pic 6 - Old strain relief. See tab that bites wire!
    Also some stoves have the AC cord strain relief part of the back panel and can easily fall out. Drilling a hole in the back of the stove body and using the new strain relief can also make stove servicing easier.
     

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  2. jpeterson2322

    jpeterson2322
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    Feb 11, 2018
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    You should redo your ground wire. Self tappers don't give a proper ground connection. Scrap some paint off and through bolt it with 10-32 or get a 10-32 ground screw and tap the metal (short green screw in electrical dept).
     
  3. Don2222

    Don2222
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    Feb 1, 2010
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    Yes, it is a much better ground than where it was before under a rusty painted screw on the back panel! You are correct that a nut and bolt would be better. How is your stove’s ground wire connected?
     
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  4. jpeterson2322

    jpeterson2322
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    Feb 11, 2018
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    It doesn't matter where you put it as long as you're bonding the metal housing of the stove. Electrical code says you need so many threads in contact with metal or through bolt it. Don't remember of the number (1.5-2.5?) but a self tapper won't have 1 full thread in contact making it code issue/ safety issue.
     
  5. Don2222

    Don2222
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    Yes but the threads on a bolt will not have any more threads in contact with the metal than a screw or self tapper because the sheet metal is the same thickness. Also the bolt threads will not be in as much contact with the metal because it did not make the hole like the self tapper. In fact the bolt may not even touch the sides of the hole.
    The material or alloy used in the bolt is made out of must be a big factor as well, some metals are not very good conductors that is why I chose stainless steel.
     
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  6. jpeterson2322

    jpeterson2322
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    Feb 11, 2018
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    I didn't make the rule, just follow it. What you have isn't right and am just trying to help. The picture is from my code book.
     

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  7. Don2222

    Don2222
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    Feb 1, 2010
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    Thanks very much for posting that pic. This info is very helpful. If I read between the lines, the reason for the nut and bolt is because the threads on the nit count towards the bonding of the ground. Thank-you
    I am sure many of the older pellet stoves do not comply with the newer code and if they did it would prevent some problems. Last year I worked on a 20 year old Harman invincible with the old terminal block for connecting wires. None of the newer stoves have terminal blocks that expose wires that carry AC current. In this case I saw that the ground was not very good and like in all the older wiring the neutral wire was not seperate from the ground wire like it should be. Therefore I replaced all the wires with a new updated wire harness and installed an Igniter so it would auto lite!
     
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