10kw vs 7kw heat strip w 50 amp stab-loc breaker. Advice needed

Discussion in 'HVAC Heating & Cooling' started by doublesharp, Mar 2, 2013.

  1. doublesharp

    doublesharp New Member

    Messages:
    4
    Location:
    33471
    Hello. I'm located in S Florida and needed to replace my 2 piece a/c. I'm using a licensed contractor and bought the Rheem/Ruud brand value series 3 ton 13seer RHSL HM3617JA air handler and 13AJN36aA01 outside unit. My sales agreement calls for a 10kw heat strip. The space the air handler fit was very narrow and the 17.5" box on the air handler fit only by removing the screws to get it through the doorway. The narrow width of the air handler is the reason I chose Rheem.

    The 10kw heat strip called for a 60amp circuit breaker and I have a 50amp stab-loc breaker in a 200amp Federal Pacific Electric panel from the mid 1960s when the house was built. The tech installed the 10kw for a temporary heat source and came back the next day and installed the 7kw heat strip. The 10kw was considerably warmer but it did trip the breaker once. I reset the breaker and it functioned fine. The newly installed 7kw heat strip tripped the breaker after less than 10 minutes operation and continued to trip the breaker after a few minutes operation so I've turned the unit off. The heat output was lukewarm at best.

    The breaker is a Federal Pacific Stab-loc 50 amp and the tech said they were out of production and expensive so rather than upgrade my breaker to the 60 amp that a 10kw heat strip calls for he would down grade the heat strip so it would be appropriate for my 50amp breaker.

    Since the breaker continues to trip I'm assuming it is weak, although it never caused a problem with the 25 year old 3 ton a/c unit I replaced. I called the contractor and asked to have the breaker replaced with a 60amp and the 10kw heat strip re-installed as per our sales agreement. Am I thinking correctly that a 7kw heat strip puts out 30% less heat than a 10kw strip?

    A quick internet search shows replacement FPE stab-loc 60amp breakers mfgd by Connecticut Electric are available on Amazon for around $50 shipped and the few performance reviews are positive.

    Any comments or suggestions? The code enforcement inspector hasn't inspected yet. Assuming he comes Monday, and that I haven't heard from my installer by then, should I keep my complaint between the ac installer and myself or should I tell code enforcement that the unit is tripping breakers. I don't want to get in a bureaucrat maze but until they sign off I've got a bit of leverage. I'm not asking the installer to buy the breaker but I do think he should do the install and re-install the 10kw heat strip as per the original agreement at no charge.
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    7 kw is only 28 amps, and should not trip a 50 amp breaker. 10Kw is about 41 amps.

    Connecticut Electric is possibly the only company making replacement breakers for the defunct FPE. If you google FPE, you may decide to replace the entire panel. You need to have a qualified electrician check out why your breakers are tripping.
  3. doublesharp

    doublesharp New Member

    Messages:
    4
    Location:
    33471
    Kudos to my installer. He responded to my phone message by sending a tech out with the 10kw heat strip and a 60amp FPE breaker that he found in his used parts box. It looks like a Connecticut Electric breaker and everything is working good so far. He charged me $40 for the used breaker and said if it proves faulty he will replace it with a new CE breaker. The 10kw strip puts out noticeably more heat than the 7Kwand I'm more than satisfied with the customer service. It's all good and thanks for the reply.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,824
    Location:
    New England
    You may or may not give him the kudos if the wire run is not sufficient for a 60A breaker, as it just created a code violation and a potential safety issue! Given the load of the heaters on the existing CBs in the panel, you may have other issues that need to be addressed. That panel has given others problems. This may be the tip of the iceberg.

    Overloading the old breaker (and possibly wire) may have burned the bus on the panel making it imperative to replace the panel.
  5. doublesharp

    doublesharp New Member

    Messages:
    4
    Location:
    33471
    OMG...we're all gonna die!

    More weasel words in that last post than I've seen since Bill Clinton's "meaning of is" testimony. ;)

    If ifs and buts were cookies and nuts we'd all have a Merry Christmas. :D

    Got down to 37 here in the swamp about daylight but temp stayed a toasty 68 inside.
  6. DonL

    DonL Jack of all trades

    Messages:
    3,815
    Location:
    Houston, TX

    You normally don't install a larger breaker unless you install larger wire. It should have been properly sized when it was originally installed.

    The way it is now the wire could be producing more heat than normal.

    If the wire size is correct then you should be OK.

    If the wire size is to small then the larger breaker does not provide the desired protection, and the wire and connections can get hot.


    It's better to be safe than sorry.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,824
    Location:
    New England
    The breaker is installed to protect the WIRE in the WALL, not the thing attached at the end. Since larger wire costs money, most of the time they do not install oversized wire. Upsizing a breaker without verifying the wire is also proper IS potentially both a safety and code issue.
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