2

I'm looking to replace the aging 200A Main Panel with a new panel for additional circuits. I see a lot of 225A panels (https://www.leviton.com/en/products/lp622-mb) and interested in a 225A versus 200A. In new Main Panel, I will try and stay ahead of the 2020 NEC curve and basically install the combined AFCI + GFCI breakers. I already have whole-home surge protection to bring over.

I am confused about how I would get to use a 225A panel when the meter-box is 200A. Additionally, I want to try and not replace the meter socket due to cost, and would get this project done before November when is suspect Vermont will go with 2020 standards. I am also hesitant to replace it, due to the need for two-meter socket with main breakers in order to do net-metering. So I would either have to buy that now (and the pains that come with that service upgrade) or waste money now and buy it again later.

Due to the number of branch circuits and then that most breakers would fall into the combined breaker, I am already looking at a project cost of about $1500 for main panel. (They don't give these circuit protection breakers away, even if I went Square-D or Eaton.)

System Info

  • Vermont Home, built 1980
  • Existing Panel: 200A Cutler Murray, never replaced
  • Ground - Single ground rod
  • Meter Socket: 200A socket, replaced 15 years ago.
  • Panel problem: Rust and corrosion, likely due to flood ~1990. Breakers starting to need replacement
  • Power is overhead service, meter is located in space constrained area

Load Info

  • garage sub panel - 100A 2-pole breaker, 2-2-2 URD wire installed in conduit. Installed circa 2000. Has it's own grounding rod. Main Breaker subpanel. Garage has air compressor, welder, and car lift.

  • Shed sub panel - 50A 2-pole breaker, 2-2-2 URD wire in conduit. Installed circa 2000. Grounding Rod installed, but main lug panel. Note: likely to be replaced soon, we shall see. Has 3x 20A circuits for lights + some network gear

Future

  • Solar Panels
  • Powerwalls
  • EV unlikely

Added info from comments (updated 6/18)

After some thought, i have 3 questions.

a) Can i put a 225A main panel beyond a meter socket/meter rated for 200A? I assume no. 2) When replacing the main panel, can i preserve the pre-2008 NEC rules for the shed and garage and not run new wiring (2-2-2-2-4) to those structers? 3) with replacing the main panel, anything else i might run into? Smoke alarms? wiring to exiting outlets, etc? I know I have 12/2 wiring to everything in the house. I will likely add a second grounding rod just for good measure.

Appliances

Furnace: Propane, has 20A breaker Cooking Stove: Propane, plugs into 20A breaker Dryer: Electric, 30A AC: Portable ACs, 3 x 10,000 BTU's running during summer. considering central air Fridge: 2 running at all times freezer 1 running at all times Computers: Factor consistent 15A load

4
  • 1
    Is your only question the 200A/225A discrepancy? Or is there something else you want to know? Jun 18 at 11:38
  • Clarified question above Jun 18 at 19:42
  • Well there is no way those loads bring you anywhere near maxing out a 200A service. Remember, the 200A is two phases of 200A@120V each. The solitary 240V load, the dryer, draws 23A off both phases, but every other (120V) load only draws off one phase. Do a proper load calculation, you'll see this plain. Jun 19 at 0:45
  • The fridge and freezer are less than 1 amp (120W) each and the range is a great deal less than that... pretty much its wattage is that of the oven light, but only when the oven door is open. The A/C's are certainly under 8A each, so <1000W each. You have 48,000 watts to play with. Jun 19 at 0:49
3

"Busing" and "Main breaker" are two different things

It's like you buy a car. Maybe the car can go 105 mph but the tires are rated for 130 mph. Those are different things.

"Bus rating" is much like the tires. It's what the panel is capable of.

"Main breaker" is like the 75 mph speed limit, it's what the panel is limited to due to outside factor (i.e. service drop).

Change the main breaker to 200A

On most of these panels (can't speak to Leviton's new thing), the main breaker can be unbolted and changed to a different size.

This is an easy thing.

At this point, you have a panel with 200A main breaker and 225A busing. Who cares about a silly detail like that?

Headroom on busing gives solar a leg up

Your solar system capacity is limited by your panel size. Main breaker trip + solar trip must be <= 120% of bus rating.

Jim has a 200A bussed panel with a 200A main breaker. The solar company calculates that 120% of the 200A bus rating is 240A. Minus the 200A breaker = Jim's house can have up to 40A of solar.

Jane has a 225A bussed panel with a 200A main panel. 120% of the 225A bus rating is 270A. Minus the 200A = 70A. Jane's house can have up to 70A of solar.

...And that matters because solar panel prices are still in freefall - at a buck a watt, it's perfectly plausible to have a system that large.

PSA: You want that 50/60A electric vehicle outlet.

Yes, yes, "cold dead hands" I know. But home buyers consider it an important feature. Having that already provisioned means certain home buyers will bump their bid a couple of grand. It's about resale.

Also the presence of that port changes it from "How on earth would I ever power it?" to "Sure, I can get that welder."

You are nowhere near maxing out a 200A service.

Well there is no way those loads bring you anywhere near maxing out a 200A service. Remember, the 200A is two phases of 200A@120V each. The solitary 240V load, the dryer, draws 23A off both phases, but every other (120V) load only draws off one phase.

Do a proper load calculation, you'll see this plain.

  • The fridges are under 120 watts when it is running, and run <1/3 of the time.
  • the freezer is less than that.
  • the electric load from the gas range, is basically the oven light, but only when the door is open.
  • The portable A/C's are certainly under 8A each, so <1000W each. -The furnace only needs power for air handling, so not that much, 5-8A at 120V. But you don't run that at the same time as the A/C.

Remember, you have two banks of 200A for 120V loads. So 400A of 120V load. Already.

By the way, if those portable A/Cs are the 1-tube model, red-pill up on why they stink, and dump them, or hack them to be 2-tube models.

6
  • Interesting thought about the EV outlet adding value. At that point, wouldn't I be into a class 320 meter socket? I certainly considered chanigng out the 225A beaker for a 200A, if nothing else, just t have breathing roomin the panel for the future, and this panel does allow it. Jun 18 at 19:40
  • 1
    All depends on your actual loads. All your tools (100A garage, 50A shed) are used intermittently. The big question (for a load calculation) is: what are your big residential loads: water heater (might be 0 for gas, 30A or 40A for electric, or a lot more for on-demand electric), dryer (very little for gas, 30A for electric), heating (very little for gas, moderate for heat pump, a lot for resistance heating), air conditioning (probably not so bad in Vermont), cooking (very little for all gas, moderate for gas cooktop/electric oven, a lot for all electric), etc. Jun 18 at 20:20
  • Gas waterheater, dryer is 30A, heating is gas and fits in a 20A breaker, AC can get brutal, 3x portable AC's running at about 10,000 BTU at any given time. Cooking Stove is Gas as well. Jun 18 at 22:25
  • Thanks. So i will buy the 225A panel, replace the main with 200A, so that i have the extra availability for solar @ 70A vs 40A. So that leaves question #2 and 3 above about preserving NEC pre-2008 rules on existing installations and if replacing the panel will force me fix/upgrade anything else. Jun 19 at 4:17
  • @user2213594 and shop carefully, when a panel is marketed as "200A" that's the breaker not the busing. You may find 200A main breaker panels with 225A busing. That happens all the time with 100A panels (having 125A busing) making for many happy solar owners. This kind of expert advice is readily available at your local electrical supply house - big box stores will be clueless of course. Jun 19 at 4:53
0

I agree with @ThreePhaseEel. It seems you are asking more than one question in your post. So I am going to try and answer your first question.

What really matters in electrical circuitry is the over current protection. So whatever the size of your main breaker then that is the service size. It really doesn't matter what size the panel is (it could be a 400A panel) so long as the breaker protecting the panel is adequate to protect the service conductors.

In this case, if the main breaker on the meter is 200A, then everything after it must be sized to be protected by that main.

As far as the rest of the post you might want to repost it with a few pictures in order for everyone to fully understand your problem.

Hope this helps.

1
  • So I guess my question is, how can I get to 225a service at a low cost? Jun 18 at 15:23
0

The big difference is the size of the service drop. With a 200 amp panel you are fixed at that level since you don’t want to upgrade the service. The feeder can be sized at 84% of the main because diversity In a residential service the 225 is common with 300 amp services put those are peak short term loads that your utility is probably fused below that level because the meter base is only 200 amp rated.

I believe this is the answer on why 225 is more common.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.