Does interruptible AC service put a load on main electrical service panel breaker?

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Wolverine2349

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Metro Detroit Area
I have a 100 amp main panel to my house. I see no circuit breaker on there for the AC condenser. Outside it appears the AC condenser is connected to separate meter with its own wire. Does this mean it is on a separate circuit independent of the main 100 amp panel and thus not putting its own load on the 100 amp panel? Or is it, you just cannot see it?

Reason I ask is because I want to make sure the 100 amp panel I have is more than sufficient for the power needs for my house. I have never had any issues with it tripping, but want to make sure I am not cutting it close.

My home is 1700 square feet on a slab with no basement. Home was originally 1507 square feet built in 1971 and I added on an addition living/sun room of about 200 square feet to make it 1700 total.

I have a gas dryer, gas stove, electric oven, gas furnace. Water heater is also gas. I also had 2 dedicated 15 Amp 120V outlets on their own circuit installed when I moved in almost 3 years ago for my computer lab room of 16 computers.

For my sun/living room addon- I had a PTAC unit installed that uses 220V and maximum of 2500 watts for heating the room.

I think I am good as I have never had a problem, but want to make sure as I have heard all the hype about how all modern homes need 200 amp service panels. When they installed it, I had forgot to check and just went with the inexpensive option as I was short on money almost 3 years ago and the original panel (probably much less than 100 amps) did not have the room on the box for the dedicated circuits for my computer lab room.

So is the interruptible AC on a separate circuit from the main breaker panel,. or is it in and you just do not see it?

Assistance greatly appreciated.
 
Dennis Alwon

Dennis Alwon

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Location
Chapel Hill, NC
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Retired Electrical Contractor
I think you are good also. I suspect the meter by the a/c may be a load control device. However if the only way to shut it off is by the a/c disconnect then it must be connected to the main meter. This means the load on the wire feeding the main meter will have the a/c included.... Even if connected to the 100 amp service it is fine, IMO.
 
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Wolverine2349

Member
Location
Metro Detroit Area
Dennis Alwon said:
I think you are good also. I suspect the meter by the a/c may be a load control device. However if the only way to shut it off is by the a/c disconnect then it must be connected to the main meter. This means the load on the wire feeding the main meter will have the a/c included.... Even if connected to the 100 amp service it is fine, IMO.
Click to expand...

Thanks for your input. The AC looks to have possibly someone to disconnecting it outside as it is connected to some outside box that can be open easily that inside it says warning on it if you open it that there is shock hazard behind a thick rectangular bracket if you pull it out from the box

Do you know where all the hype about 200 amp panel service and it being standard comes from. Is it because most homes built now are 2500 or more square feet. Is it the industry trying to severely oversize to make more money.

Or is it simply to allow expansion ahead of time like if someone wanted to add a guest house, pool or sauna (which I do not intend to do) they can with a 200 amp panel easily having enough capacity where as it would be cutting it close or exceeding it with a 100 amp panel.

It also helps a lot that all my major appliances that can be gas are gas except my wall oven which is electric. And of course the major appliances which cannot be gas like the microwave, dishwasher and central AC are electric.
 
cpinetree

cpinetree

Senior Member
Location
SW Florida
Part of the 200 amp as minimum is geared toward all electric houses.
A 100 amp service, around here, is just for the pool equipment:roll:

You starting adding it all up, it gets to 200amps or more pretty quickly, at least by load calculations.
As soon as you put the water heater, range, dryer, and heat system on gas, the requirements are much less.

Many homes in this part of Florida are all electric. If they have a tankless water heater that draws 120 amps ( 3 x 40 amps), pool heater drawing 45 amps plus the dryer, range, and electric heat for the one cold day a year, you could see why a 100 amps is not even close to being workable. Soon car chargers may be added,maybe an additional 32amps?
 
G

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
160321-1500 EDT

Wolverine2349:

I am surprised this thread was allowed to proceed, but in a sense I think it is good that it has.

I see no circuit breaker on there for the AC condenser. Outside it appears the AC condenser is connected to separate meter with its own wire. Does this mean it is on a separate circuit independent of the main 100 amp panel and thus not putting its own load on the 100 amp panel?
Click to expand...
This statement means the air conditioner is not on your main panel.

Your discussion shows how little the average consumer understands about power, energy, the relationship of voltage and current, how electrical billing is determined, peak loading, the signifiance of peak loading, and average power consumption.

You are in the same area as I am, and probably provided by the same power company for both gas and electricity. We are lucky and have low gas rates. Other than air conditioning our biggest energy need for most families is home heating, water heating, and cooking. Thus, at about a 5 to 1 ratio in cost per kWH of electricity to gas it is only logical to use gas for these purposes. You are mostly doing that. I would get rid of the electric heat, unless it is used for only short periods of time.

For a much larger home I have an average of about 30 kWH of use per day. If my load is balanced, then this is an average current of 5.2 A. I have a 200 A panel and a 50 kVA pole transformer. My peak power consumption is generally below 4 kW, or if distributed as a balanced load, then a line current of 16.7 A and if totally unbalanced 33.3 A. Could I find enough stuff to plug in at once to reach 100 A? Probably not.

My electric bill usually runs between $100 and $150 per month. Greatly dependent on how many lights and computers are on for how long. I have pulled my load down from about 40 kWH per day to the about 30 kWH.

Your panel rating is based on a short time peak power use. In other words heating in the panel and peak temperature rise in the panel. I can load the panel to 10,000 A for a very short time, a dead short circuit, and not do too much damage. But longer and there is great damage. Your panel is designed for a continuous never changing load of probably somewhat under 100 A. I don't know what criteria is used to determine panel life and its current rating. It is probably based on a time current profile that in some way simulates real life.

See my website at http://beta-a2.com/energy.html my phone number is at the bottom of the page.

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