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100 Amps Panel - What are my options?
- Thread starter Jasonb2710
- Start date
Get the model number of that AC. It probably only has a 50 amp breaker for the motor-start current. Figure out what that 30 amp 240 volt breaker is driving, most likely a range or clothes dryer, and see what IT is rated to actually use, worst case.
Get an identifying model or something off that panel. It probably doesn't support tandem breakers so you'll have to combine circuits to free up two breaker spots for another 240 volt load.
Get an identifying model or something off that panel. It probably doesn't support tandem breakers so you'll have to combine circuits to free up two breaker spots for another 240 volt load.
Subpanel to increase the number of breaker slots. You could even put a 200A subpanel and derate it to 100A or even 75A or 50A by using a smaller breaker, and use it to run low current loads like lighting and 120V outlets. But you'll need to have an electrician do the load calculation for your house; if you're above the limit for that old panel, you may need to do a service upgrade.
ATPMSD
Active Member
Upgrading to 200A service is likely expensive. You will need to use tandem breakers to open up 2-slots, or use a quad breaker, but not every panel supports tandems and quads. As to load, I think most people with 100A service are able to use a 30A circuit (this will give you a charge rate of 24A) with a 14-30 outlet. Hire an electrician, get at least 3-quotes, and make sure they use a commercial grade outlet.
Good luck!
Good luck!
There are splitters too where you could share a dryer outlet https://www.amazon.com/Splitvolt-Splitter-Automatic-Switching-Between/dp/B08DLBCXXQ
Though for the price real electrical work may be close to the same cost. I would get some prices from an electrician see what they can do for you.
Though for the price real electrical work may be close to the same cost. I would get some prices from an electrician see what they can do for you.
There's also this product: DCC Electric Vehicle (EV) Charging for Condos or Full Panel Homes
Cuts power to the EVSE when load to the panel exceeds 80%, so that the EVSE can be neglected from the load calculation. However it does cost hundreds of dollars and personally, I thought it was better to spend the money on an actual service upgrade that resolves the issue once and for all.
Cuts power to the EVSE when load to the panel exceeds 80%, so that the EVSE can be neglected from the load calculation. However it does cost hundreds of dollars and personally, I thought it was better to spend the money on an actual service upgrade that resolves the issue once and for all.
A lot of AC units are allowed to be attached to breakers up to 50A, but if you actually measure the current while they're operating, they're only drawing about 12-18A (for ~3 ton units).
SkyDog
Member
I have 100 amp service to my main panel. Off of that, I have a 60 amp sub-panel in my detached garage with a Tesla Wall Connector on a 40 amp breaker. So far it's been working fine. The only big electric loads in my house are are an electric stove/oven and a dryer. Like @Sophias_dad said, find out more about the AC on your 50 amp breaker.
tandem breakers will fix your issue
www.dkhardware.com
replace your 50 with this,
give your tesla a 30 240v outlet and your set, this is what i did. Feel free to DM with questions, I used to work as an electrician.
Eaton BQ230250 Circuit Breaker with Rejection Tab, Quad, Type BQ, 30/50 A, 4 -Pole, 120/240 V
Buy Eaton BQ230250 Circuit Breaker with Rejection Tab, Quad, Type BQ, 30/50 A, 4 -Pole, 120/240 V online at DKHardware.com. Our Pool & Patio category offers a great selection of Circuit Breakers products at the best price!
replace your 50 with this,
give your tesla a 30 240v outlet and your set, this is what i did. Feel free to DM with questions, I used to work as an electrician.
ElectricIAC
Good-Natured Rascal
100 amps should be fine, even with the a/c. But you need to do a load calculation.
To do the load calculation, you need to check the rated current draw of the electric devices in your home, not just what you see on the circuit breaker. So look at the a/c unit, check your electric stove, dryer, etc. and make a list of the current draw of each device at 120v or 240v. Once you have a list, you can either look online how these are derated, or check with your local building department.
When I was renovating my house, I was already working with an engineer to design the power system and to apply for permits, so he did the calculation for me. But it starts with a complete list of electric devices and their power usage. I was close to the limit so I ended up with a 32amp EVSE on a 40amp 240v line, which is fine for off peak (midnight to 6am) charging.
To do the load calculation, you need to check the rated current draw of the electric devices in your home, not just what you see on the circuit breaker. So look at the a/c unit, check your electric stove, dryer, etc. and make a list of the current draw of each device at 120v or 240v. Once you have a list, you can either look online how these are derated, or check with your local building department.
When I was renovating my house, I was already working with an engineer to design the power system and to apply for permits, so he did the calculation for me. But it starts with a complete list of electric devices and their power usage. I was close to the limit so I ended up with a 32amp EVSE on a 40amp 240v line, which is fine for off peak (midnight to 6am) charging.
I'm not an electrician, but OP's panel does not appear to be an Eaton/Cutler-Hammer. The shape/proportion of the breakers appears wrong.tandem breakers will fix your issue
Eaton BQ230250 Circuit Breaker with Rejection Tab, Quad, Type BQ, 30/50 A, 4 -Pole, 120/240 V
Buy Eaton BQ230250 Circuit Breaker with Rejection Tab, Quad, Type BQ, 30/50 A, 4 -Pole, 120/240 V online at DKHardware.com. Our Pool & Patio category offers a great selection of Circuit Breakers products at the best price!
replace your 50 with this,
give your tesla a 30 240v outlet and your set, this is what i did. Feel free to DM with questions, I used to work as an electrician.
That's sorta why I asked for a panel model number in comment #2
ATPMSD
Active Member
I am not an electrician, but IF you are comfortable in working in a life breaker box, and you have a digital clamp amp meter, you can figure out the available capacity youself (OK everyone, check me on this):
- A 100 AMP panel can deliver 24 kW of power. Since we are looking at "continuous load" items you miltiply this by 80% to arrive at your upper limit of 19.2 kW
- Open the panel and turn on everything. OK, you really do not need to turn on every light, but certainly the big stuff.
- Using the AMP meter CAREFULLY measure the load on each of the two legs. Now multiply the value for each leg by 120, add them togther, then divide by 1,000 to get your continuous load in kW. For eaxmple, if leg one is 50 amps and leg two is 52 amps. then 50a * 120v + 52a * 120v = 12,240 watts, dividing this by 1,000 makes this 12.24 kW
- Subtract whatever value you get from 19.2 kW. this will be your available load. In this example that would be 19.2 kW - 12.24 kW = 6.69 kW. If the value you get is greater than or equal to 5.76 kW you can support a 30 amp circuit (30 amps * 80% * 240v / 1,000= 5.76kW). If it is less than 5.76 kW but more than 3.84 kW, you can support a 240v 20 amp circuit (6-20 outlet)
More detail about my panel. Can I use tandem breaker on this?
Thank you everyone for all the advices. I really appreciate it!
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@Jasonb2710 I ran into the same problem and got several quotes from switching to quad breakers to a 200amp service upgrade. The cheapest non-permitted work that anyone would quote me was about $700 to add a 50amp breaker and install a NEMA 14-50 outlet. A service upgrade would have set me back at least $4000.
Ultimately, what I did was buy a splitter (NeoCharge) for my 30amp dryer outlet for $450. Works great for my use case, to be honest. Only reason I didn't go the $700 route was because I'd probably end up doing a service upgrade and replace the panels in the future anyway.
Ultimately, what I did was buy a splitter (NeoCharge) for my 30amp dryer outlet for $450. Works great for my use case, to be honest. Only reason I didn't go the $700 route was because I'd probably end up doing a service upgrade and replace the panels in the future anyway.
You're very fortunate if you can do a service upgrade for less than 5 figures. This usually means that you have the service line overhead; I had to pay $7000 just to have someone install the new service line and conduit. And then another $2500 or so to do 400A service instead of 200A because I wanted to make sure that I never had to pay someone $7000 to install a conduit again.
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