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Thread: Hot box ?

  1. #1
    Hunter Hoffman's Avatar
    Hunter Hoffman Guest

    Default Hot box ?

    Home has a hot smell coming from the Breaker box at times when Hot water is in heavy use. Took the tempature of the breaker and found that the breaker was 10 to 15 degrees above the temperature of all the rest of the panels breakers. Replaced the breaker and still have the problem under heavy use. Nothing including the wires are hot but still have that smell. I have made sure all wires are tight. Where to look next?

    F.I.R.E. Services

  2. #2
    Join Date
    Aug 2008
    Location
    Maryland
    Posts
    1,898

    Default Re: Hot box ?

    Just the fact that you are drawing current thru the breaker will generate heat. A typical WH element is 4500 watts.

    Did you check the buss connections when you replaced the breaker? Did you think the amount of temperature rise was unusual?


  3. #3
    Hunter Hoffman's Avatar
    Hunter Hoffman Guest

    Default Re: Hot box ?

    No I didn't think it was high, I just can't determine why the smell of something similar to hot plastic keeps coming out of the box when the tank is heating.


  4. #4
    Join Date
    Dec 2008
    Location
    Mesa, Arizona
    Posts
    45

    Default Re: Hot box ?

    Hunter,

    What method did you use to determine temperature?
    Infrared thermometers require you to be very close to the object for an accurate
    temperature. Spot size and such. Trying to determine wire temp is very difficult
    An infrared camera may tell you more.

    What type of panel? Size of breaker? Wire gauge?

    Just some questions to help us help you.
    Pictures of panel will help.

    Jeff Moore AZ Cert#49250
    Level II Thermographer
    http:www.quantumhomeinspections.com

  5. #5
    Hunter Hoffman's Avatar
    Hunter Hoffman Guest

    Default Re: Hot box ?

    Crouse -Hines Panel, 10 ga wire, 30 amp breaker. Let me say that this is only a recient problem on a house that is 25+ years old. Temperature reading close with inferred meter also hands on touch nothing excessively hot. I thought something internal in the breaker might be failing is why I switched it out.


  6. #6
    Join Date
    Jul 2008
    Location
    Snowbird (this means I'm retired and migrate between locations), FL/MI
    Posts
    4,086

    Default Re: Hot box ?

    Just throwing this out there since there isn't much information provided - 25 yrs old. Might need to torque down some of your connections i.e. neutral. Might also be a loose or corroded connection to the main lugs or behind the meter head or your service drop or lateral - not a job for the DIYer. Sometimes the electric utility can check this out for you, sometimes they require a referal from an electrician after they've first checked out the panel, measured voltages, etc.. Assuming an electric storage type not tankless WH with a continuous use demand type situation - is this for domestic HW or are you using for hydronic heat? How did the insulation look? Do you have a main breaker or split bus panel? Secondary circuit protection & disconnect, did you check that? Are both elements functioning - or is there some other reason for the "heavy use"?


  7. #7
    Roger Frazee's Avatar
    Roger Frazee Guest

    Default Re: Hot box ?

    I'm assuming your using a infrared tester with a laser pointer? Did you take an amp test on the wires connected to the heater breaker? Did you shoot the temp of the breaker terminal? What wire insulation is connected to the breaker 60C...90C?

    A temperature test as compared to the other breakers may not tell you a whole lot. The breaker terminal will be considerably hotter than the molded case in a max amp or close situation.

    The breaker you replaced showed no signs of discoloration from heat?

    I would take a close look at the main breaker as to temperature and lug tightness. Do an amp test and voltage test under load from the heater and without a load from the heater. Any major differences between readings on the two hot legs could help point you in the right direction.


  8. #8
    Hunter Hoffman's Avatar
    Hunter Hoffman Guest

    Default Re: Hot box ?

    Thanks for the advice gentlemen. Having read every one of your thoughts it made me re-think the issue. Checked the draw in amps, wire size, loose fittings, knowing that the system has worked for 25+ years and everything on the interior of the service panel was up to snuff left me with only one place left to go. OUTSIDE! Went and pulled the meter and there was the problem. Corrosion had developed on one of the feeders and had built up resistance causing heat and failure of the insulation. (Bingo smell) amazingly it had melted back about 4" and stopped. The aroma had traveled threw the conduit.


  9. #9
    Join Date
    Jul 2008
    Location
    Snowbird (this means I'm retired and migrate between locations), FL/MI
    Posts
    4,086

    Default Re: Hot box ?

    HH,

    Thanks for the update.


  10. #10
    Hunter Hoffman's Avatar
    Hunter Hoffman Guest

    Default Re: Hot box ?

    HG
    You were the one that made me think outside again I had dismissed it as a last resort.
    thanks
    HH


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