Fried a Breaker :(

Discussion in 'Electrical Forum discussion & Blog' started by JerryR, Sep 13, 2020.

  1. JerryR

    JerryR Active Member

    Joined:
    Jul 27, 2011
    Location:
    Florida
    Came back to vacation cabin after being gone for a week. I turned on the breaker to the Shed/barn sub panel. I heard the well and house pumps kick on. A little while later I went to the shed/barn to reset the clocks on the water softener. I thought a smelled a whiff of electrical burning smell but couldn’t track it down. Everything was working fine.

    The next afternoon, my wife said, we have no water at he house. Huh?

    I went to the shed and water pressure to the house side was Zero? OK. I tapped the pressure switch, nothing. Went to the breaker sub panel and as soon as I touched the 15 amp double pole pump breaker the pump turned on. Huh? This isn’t right.

    so I went back to the house, got my meter and some tools. I turned off the 60 amp house breaker that supplies the shed sub panel and went to the shed. I pulled the 15a 240 house pump breaker and it was fried at the bus. I pulled the 15 amp 240 well pump breaker and it was fried at the same buss side. The bus connector was granulated due to overheating

    So trip to HD for a new sub panel and a couple of 15 a 240 breakers. The nearest supplier with parts in stock was a Home Depot 1 hr and 15 minutes away. Ugh, 3 hour round trip.

    Came back to the cabin, replaced the sub panel and new breakers. WHAT? House pump won’t turn on? Pulled the meter out and I had a defective new 15 amp 240 breaker.

    Another 3 hour round trip to HD. This time I bought an extra 15 a 240 breaker. Put everything back together with new sub panel and a pair of new breakers.

    FYI, I checked current draw on the 15 amp 240 breakers. Only drawing 8.1 amps per breaker with pumps running.

    Here’s the fried breaker

    [​IMG]
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Impressive and scary photo.

    Is that a 3/4 or 1 hp pump? Does the pump maker recommend a 15 amp breaker?

    Not that this is the fault of using a 15 vs a 20. Getting a new subpanel I expect.
     
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  4. JerryR

    JerryR Active Member

    Joined:
    Jul 27, 2011
    Location:
    Florida
    3/4 HP pump. I don’t know what manufacture recommended for breaker size. It’s wired with 12 AWG THWN in a 1/2” PVC conduit raceway. It’s been wired for about 20 years like this. A 15 amp breaker should not be a problem since it’s only drawing 8 amps.

    As you stated the failure had nothing to do with breaker size. It was due to high resistance at the buss connection.

    A New sub panel has been installed. To bring it up to code, I need to install a ground rod and connect to the sub since it’s in a detached building. A project for next weekend when I come back.
     
  5. JerryR

    JerryR Active Member

    Joined:
    Jul 27, 2011
    Location:
    Florida
    Picture of new sub panel before 7/8” hole drilled on top to accept the 1/2” pvc conduit and before solid copper ground wire to ground rod installed.

    [​IMG]
     
  6. Stuff

    Stuff Well-Known Member

    Joined:
    Mar 7, 2013
    Location:
    Pennsylvania
    Do you have a disconnect at the shed? The ground rod needs to connect there. If you don't have a disconnect then you need to add one. Code only allows 6 "throws of the hand" before you need a main breaker. An indoor panel would have the knock-out on top that you need.
     
  7. JerryR

    JerryR Active Member

    Joined:
    Jul 27, 2011
    Location:
    Florida
    Stuff,

    This all happened on a Sunday at a cabin in the middle of nowhere. Searched for parts and closest was 1-1/2 hours away. I used the same Eaton outdoor box that was there originally. It was available at HD 60 miles away and I needed to do this quickly since we had no water.

    I realized without a disconnect it violated the 6 throw rule. I just ordered a BR1020B100FRNV from Lowe’s for $54 with military discount. This box would give me ability to have a main breaker in the box and still be able to use my existing breakers. It’s a cleaner solution, less work than installing a disconnect and it gives me more room.
     
    Last edited: Sep 18, 2020
  8. JerryR

    JerryR Active Member

    Joined:
    Jul 27, 2011
    Location:
    Florida
    Ok. I replaced the panel today with one that has a 60 amp main for a disconnect. I still have to label the 60 amp main breaker on the top left side. My label maker is in my RV. The main breaker is locked down via screw and the breaker terminals are shielded using the Eaton shielding kit.

    I still need to install the ground rods and connect it to the ground bus. Another run to Home Depot tomorrow. I’m not looking forward to drive the ground rods.

    The panel is an Eaton with the same box size and format layout. It went quickly.


    [​IMG]
     
    Last edited: Sep 28, 2020
    Stuff likes this.
  9. JerryR

    JerryR Active Member

    Joined:
    Jul 27, 2011
    Location:
    Florida
    Ok one more question re: wire size for ground rod for this 60 amp sub panel. Can #8 solid be used or must it be #6 solid? I believe #6 is minimum.
     
  10. Stuff

    Stuff Well-Known Member

    Joined:
    Mar 7, 2013
    Location:
    Pennsylvania
    You can use 8 gauge for GEC but it can't be exposed. Go to 6 and then can run along the surface as long as not exposed to physical damage.
    NEC 250.64(B)(3) Grounding electrode conductors smaller than 6 AWG shall be protected in RMC, IMC, PVC, RTRC-XW, EMT, or cable armor.
     
  11. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    The picture of the fried breaker, is that the original one or the defective new one?
     
  12. JerryR

    JerryR Active Member

    Joined:
    Jul 27, 2011
    Location:
    Florida
    The fried breaker was the original one. Both it and the other one attached to the same bus stab on the opposite side were burnt the same way. Obviously there was a poor high resistance contact at the bus/breaker connection which heated up that bus stab. That bus stab was granulated due to heat damage.

    The defective newly purchased breaker while it visibly looked good one pole was electrically “open” when breaker was turned to ON position.
     
  13. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    It's amazing how much heat can develop from a poor connections.
     
  14. DonL

    DonL Jack of all trades Master of one

    Joined:
    Mar 30, 2011
    Occupation:
    Rocket Scientist
    Location:
    Houston, TX
    Yes it is.

    All of the electrons gather around a loose connection and have a barbecue party. :eek:
     
  15. JerryR

    JerryR Active Member

    Joined:
    Jul 27, 2011
    Location:
    Florida
    OK, Done!

    New panel with 60amp main breaker has been installed
    30 feet of 6 AWG bare solid copper ground attached to sub panel ground bus bar running to a pair of 8’ long 5/8” ground rods driven into ground behind shed spaced 8’ apart.

    I’m now sitting in my recliner and resting my right arm after driving in those ground rods. Driving in those rods in 90 deg plus heat outside today wasn’t much fun but the satisfaction makes it worth it.

    I feel much better about this sub panel.

    Now on to one of the next never ending projects.
     
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