Changing Entire Panel (Details)

Discussion in 'Electrical Forum discussion & Blog' started by molo, Sep 4, 2011.

  1. molo

    molo New Member

    Messages:
    840
    Location:
    cold new york
    Hello,

    I have an older 100 amp panel. I am considering changing it. The panel serves a 3-bedroom home. Is it within code to use another 100 amp panel? Is it required to go larger?

    Thanks,
    Bill
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,237
    Location:
    Land of Cheese
    100 amps in a 3 bed would be pretty common. If you run the numbers you will probably see that it is fine, which saves you from having to replace the feeders. I would look for a minimum of 24 circuit capacity for a 1000-1500 sq home.

    If you have a lot of devices requiring 220V- electric water heater, air compressor, welder, hot tub, central air, cooktop, oven, etc, etc, then I would seriously consider going to 150 or 200A with more space for additional circuits.

    Remember, you only want to do this once.
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,817
    Location:
    New England
    If you ever want to remodel the kitchen, bath, or upgrade anything, you'd probably want more room in the panel than a typical 100A one would provide. Now, you may not need more actual power capability, but generally, you'd use a larger supply on a larger panel (you could always buy a 200A main panel, but substitute a 100A main breaker to match your supply). Most modern kitchens have all sorts of power devices: microwave, frig, stove, vent, dishwasher, the counters, garbage disposal. Now, they all don't need their own dedicated supply branch, but many of them are recommended to have them by the appliance manufacturer. It also makes life easier when it comes time to do any repairs - you can shut only that one thing off while you deal with the problem without impacting potentially numerous other things. Modern codes often require more circuits, but replacing the panel would be grandfathered, most places meaning you wouldn't need to run new circuits unless you were also remodeling say the kitchen. It would be nice to acutally have the space for them, though.
  4. molo

    molo New Member

    Messages:
    840
    Location:
    cold new york
    1.Yes, I recently saw a panel in a new Homewood Suites room (with kitchen). It appeared there was a circuit for nearly every appliance and outlet!

    2.I like your point about using a 200 amp box and putting a 100amp main allowing for upgrade to 200 amp in the future.

    3. per cacher-chick's statement; Is there enough room for 24 circuits in a 100 amp box?


  5. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,237
    Location:
    Land of Cheese
  6. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    Size the service by the calculated load that the service will see.

    I have always used a 30/40 panel of which ever brand name I was using at the time. This panel will hold 30 1 inch breakers or up to 40 by using the mini breakers.
  7. Jim Port

    Jim Port Electrical Contractor

    Messages:
    156
    Location:
    Maryland
    Adding a subpanel is also an option when only more breaker spaces are needed.
  8. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

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    Location:
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    You should really run a load calc to determine the correct size. For an average 3 bedroom all gas house 100 is probably fine.

    Jason
  9. molo

    molo New Member

    Messages:
    840
    Location:
    cold new york
    Decided on a Cutler Hammer 100amp BR model with 30/30 (with 6 20 amp breakers and a double-pole 30 amp breaker) $81
    The electrician said it was fine, and it would be easy to find breakers for it.
    Question: Can this panel be updated if necessary in the future to a 200amp by buying a 200 amp main breaker? My guess is no, but I'm hoping the pros can answer this. (I asked the electrician and he rattled off an answer that I didn't quite follow)

    Thanks,
    Bill
    Last edited: Sep 6, 2011
  10. jwelectric

    jwelectric Electrical Contractor/Instructor

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    2,529
    Location:
    North Carolina
  11. nukeman

    nukeman Nuclear Engineer

    Messages:
    708
    Location:
    VA
    You could go the other way, though. It would cost a little more for the 200A panel and then you'd have to also pickup a 100A main breaker. The 200A breaker that comes with the panel could be kept on hand for a future upgrade to the service.
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,817
    Location:
    New England
    In theory, the bus bars are sized for the max load, so a 100A panel's bus bars and other internals would be too small to support 200A at full load. WHether that is always the case is another issue, but the labeling would make it a violation, regardless.
  13. mrmedic

    mrmedic Junior Member

    Messages:
    57
    Location:
    Delaware
    If you are thinking of getting a new 100 amp box, Most of the time the only difference in changing out the 100 and going with a new 200amp might be the down feed wire and meter box. Price should not be that much different. At least around here it isn't. What was the electrician going to charge for the new 100 amp set up? I would just go with the new 200amp.
  14. ActionDave

    ActionDave Electrician

    Messages:
    345
    Location:
    Colorado
    200A, 40 circuit panel is SOP for a panel change+upgrade for me. The cost is not that much greater than a smaller panel and they can be cheaper.
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