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  1. #1
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    Feb 2011
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    Default undersized panel?

    All electric home built in 1986. 1200sf. Service is 125 amp. (appears to be 4/O stranded aluminum service cable(s) Electric dryer, range, water heater and cadet, and baseboard heat. Do you think this should be a 200 amp service? I didn't notice anything wrong or defective (except it was a FedPac panel). Just curious what your thoughts are out there. Seemed like a lot of electrical appliances for that size of main breaker.

    Steve

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  2. #2
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: undersized panel?

    The only real way to know is to perform a load calculation. Without that you're just guessing.


  3. #3
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    Feb 2011
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    Oregon
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    Default Re: undersized panel?

    That's kinda what i thought. And that goes way outside the scope of my inspection. Just curious. Thanks for the reply.


  4. #4
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    Feb 2009
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    Southern Vancouver Island
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    Default Re: undersized panel?

    Quote Originally Posted by Steve C. View Post
    All electric home built in 1986. 1200sf. Service is 125 amp. (appears to be 4/O stranded aluminum service cable(s) Electric dryer, range, water heater and cadet, and baseboard heat. Do you think this should be a 200 amp service?
    Nope.
    I see a lot of electric heat here, 100 amps is not unusual for a house that size, 125 is a bonus.

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

  5. #5
    Join Date
    Mar 2007
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    Santa Rosa, CA
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    Default Re: undersized panel?

    Quote Originally Posted by Steve C. View Post
    All electric home built in 1986. 1200sf. Service is 125 amp. (appears to be 4/O stranded aluminum service cable(s) Electric dryer, range, water heater and cadet, and baseboard heat. Do you think this should be a 200 amp service? I didn't notice anything wrong or defective (except it was a FedPac panel). Just curious what your thoughts are out there. Seemed like a lot of electrical appliances for that size of main breaker.

    Steve
    Steve,

    If you feel it is undersized, there is nothing wrong with mentioning it and deferring to an electrical contractor to perform a load calc.

    Department of Redundancy Department
    http://www.FullCircleInspect.com/

  6. #6
    Join Date
    Oct 2011
    Location
    Eastern Shore of MD, NEC 2008
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    94

    Default Re: undersized panel?

    4/0 is a bit over sized for 125A.

    Any ways. Write up that FPE panels have had problems, I would not elaborate, and that the panel should be checked and a load calculation performed.

    As a FYI to you, residences rarely see even a 100A on average.


  7. #7
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
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    26,243

    Default Re: undersized panel?

    Quote Originally Posted by Steve C. View Post
    All electric home built in 1986. 1200sf. Service is 125 amp. (appears to be 4/O stranded aluminum service cable(s) Electric dryer, range, water heater and cadet, and baseboard heat. Do you think this should be a 200 amp service? I didn't notice anything wrong or defective (except it was a FedPac panel). Just curious what your thoughts are out there. Seemed like a lot of electrical appliances for that size of main breaker.

    Steve
    If all has been adequate for the occupants since 1986, then the service size is probably adequate.

    If the service had not been adequate for the appliances I suspect that the service would have been upgraded a long time ago.

    The other comments on replacing the FPE panel apply.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  8. #8
    Join Date
    Mar 2009
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    Default Re: undersized panel?

    Load calcs for NEC compliant installations haven't changed much for a long time. Whether or not the service "works" is a bit different than if it is adequate for the calculated loads.

    In this case, the watts per Sq. Ft. used to calculate the heat needed will either make the service too small or adequate. I plugged in standard values for general lighting, small appliance circuits, laundry, range, dryer, and water heater - then estimated heat at 6 watts per sq ft. The load calc shows a 127 AMP demand load and would require a 150 AMP service. The 6 watts is an average in newer residences but older ones are usually around 10 watts, depending on zone.

    Things get kind of tight if you figure things like a disposer, dishwasher, refrigerator, microwave, etc.

    Keep in mind the load calc takes into account that not everything is always on at once so when it shows a service is too small it's possible there may be issues if a user isn't a bit on the conservative use side. Average use is a poor indicator of peak use because most days and nights use will be light compared to meal times and /or laundry day(s).

    Not many people can afford to use 100 AMPs or more all day long, and service wire sizing assumes that doesn't happen often. It is the "when it does" that has to be accounted for in sizing things though.

    Occam's eraser: The philosophical principle that even the simplest solution is bound to have something wrong with it.

  9. #9
    Garry Blankenship's Avatar
    Garry Blankenship Guest

    Default Re: undersized panel?

    There is a kind of checks & balances system in play. The utility company will not connect a service unless it has been permitted and approved. At one time this was "approved" by the system. The calculations required for determining service size are pretty conservative. Diversity, ( the likelyhood of all things being on full tilt at the same time ), is not given much consideration by the code. Just look at the size of the wires the utility company uses and you'll see they do take diversity into consideration. Things change, but it's not a Home Inspector's job to prove a code infraction. There are ways to question the adequacy of the service size in your report.


  10. #10
    Join Date
    Mar 2009
    Location
    Colorado Front Range
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    601

    Default Re: undersized panel?

    Quote Originally Posted by Garry Blankenship View Post
    There is a kind of checks & balances system in play. The utility company will not connect a service unless it has been permitted and approved. At one time this was "approved" by the system. The calculations required for determining service size are pretty conservative. Diversity, ( the likelyhood of all things being on full tilt at the same time ), is not given much consideration by the code. Just look at the size of the wires the utility company uses and you'll see they do take diversity into consideration. Things change, but it's not a Home Inspector's job to prove a code infraction. There are ways to question the adequacy of the service size in your report.
    Actually the codes take diversity into account pretty heavily. Utility conductor size is really a poor indicator of what the NEC takes into account. Overhead utility wires are in open air and may use insulation types not common to structure wiring. Sizing service conductors for a multi-family residence just give more room for diversity sizing than a single residence does. #4 Aluminum in open air shouldn't have any issues with a 200 AMP service given proper insulation types, and #6 seems to work pretty well. The deal with newer resi services is that it's a wash cost wise (pretty much) between a 125 and a 200 AMP service, and a 200 gets installed by default many times. The 200 AMP service in these cases will never come close to capacity.

    Resi services often see minimal use most hours of the day and get "bombed" in the hours after work till bedtime with A/C or heat, meal prep and cleanup, laundry getting done, bathing, entertainment, computer use, etc.

    There were many, and still are, areas where a piece of paper signed by the installer is all that's needed to get a utility to connect. A formal inspection has never been part of their process. If this situation changes so an AHJ comes into play, you can have a majority of services "not up to code" because code compliant work was never required.

    Occam's eraser: The philosophical principle that even the simplest solution is bound to have something wrong with it.

  11. #11
    Join Date
    Oct 2009
    Location
    michigan
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    421

    Default Re: undersized panel?

    It has already been stated that a load Calv is needed, possibly.
    The load Calv rules would be those at time of construction.
    Additional loads since then would be added.
    Best IMHO, would be to state that the service size is questionable, as that of the panel type.

    Important to remember that your talking about 125 amps @230 volts and this avails 250 amps @ 115 volts.
    I still have a 100 amp service in a 2300 sq/ft home with a machine shop in my garage.... never tripped the main or any breaker for that matter. Appliances are gas. No need to do a calc... I know I'm over, that is to say, if I were to have issues.
    As an AH, I seldom require a load Calv because of electrical additions unless I believe there will be an issue with the main tripping or a quick punch of the calculator puts the load in gross violation.
    Commercial or Industrial is a different matter.


  12. #12
    Join Date
    Mar 2007
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    Ormond Beach, Florida
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    26,243

    Default Re: undersized panel?

    Quote Originally Posted by bob smit View Post
    I still have a 100 amp service in a 2300 sq/ft home with a machine shop in my garage.... never tripped the main or any breaker for that matter.
    Ahh ... another FPE panel owner.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  13. #13
    Join Date
    Oct 2009
    Location
    michigan
    Posts
    421

    Default Re: undersized panel?

    No stinking Forbidden Panel Exhaust in my house.
    Just sold a replacement panel today they have a Zensblo.


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