100 Amps Panel - What are my options?

[Sophias_dad]

More detail about my panel. Can I use tandem breaker on this?

Thank you everyone for all the advices. I really appreciate it!

I'm unable to find documents about that panel, but from the diagram, the bottom two breaker spots on each column appear to be able to take tandem breakers. They may be neigh impossible to find, and you'd have to move one of the 240V breakers that are in those spots up into a non-tandem-capable area.


This is a task for an electrician.

 

[Sophias_dad]

The 30 amps breaker is for double microwave oven combo. These are all I can find:

So your AC wants 27 actual amps, and your oven combo actually says it wants 30 amps or so. Use them at the same time and you are at 57 amps.

If it were my house, I'd expect to be able to get 24 amps for EV charging reliably. Might be able to stretch it to 32 with some luck.

 

[STS-134]

So your AC wants 27 actual amps, and your oven combo actually says it wants 30 amps or so. Use them at the same time and you are at 57 amps.

If it were my house, I'd expect to be able to get 24 amps for EV charging reliably. Might be able to stretch it to 32 with some luck.

Except that's not how you do a load calc. You take 3 watts/sqft, then 1500 watts per 20A appliance circuit, 1500 watts per laundry circuit, and add in the nameplate ratings, in watts, of all major appliances (including car chargers) but excluding HVAC. You take 100% of the first 8000 watts and 40% of everything over 8000 watts. Then you add to that the wattage of your HVAC system and get a total number of watts, and divide by 240 to get amps.

Note that the oven combo and car chargers get multiplied by 0.4 (or at least, the portion of them that exceeds 8kW). This accounts for the fact that you're unlikely to use everything at the same time.

 

[Rocky_H]

You can easily free up more room by getting double breakers.

"You can [possibly] free up more room by getting double breakers."
There--fixed that for ya.

tandem breakers will fix your issue

"Tandem breakers [might] fix your issue."
There--fixed that for ya.

It bothers me how many people tell this to people like it's always possible. It sometimes is, but a significant portion of the time, it's not. And it's not just really old and obscure panels that can't take tandems and quads. My house was built in 1996, and has a very mainstream brand and product line of SquareD Homeline. But it's a 125A main, so it's a smaller type of panel, and it's just built to not allow any tandems or quads.

So let's be a little more reasonable in offering it as an option to check into, rather than an assurance that it can always be done.

 

[ATPMSD]

To further @Rocky_H‘s point, the words you are looking for on a breaker box are something like:

This one supports tandem breakers: Homeline 125 Amp 12-Space 24-Circuit Indoor

While this one does not: PowerMark Gold 125 Amp 24-Space 24-Circuit

 

[PJFW8]

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!

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.

I really like this option! Cheap and simple. Not a fit for my panel, but luckily I had extra slots and a free electrician!

 

[Sophias_dad]

Except that's not how you do a load calc. You take 3 watts/sqft, then 1500 watts per 20A appliance circuit, 1500 watts per laundry circuit, and add in the nameplate ratings, in watts, of all major appliances (including car chargers) but excluding HVAC. You take 100% of the first 8000 watts and 40% of everything over 8000 watts. Then you add to that the wattage of your HVAC system and get a total number of watts, and divide by 240 to get amps.

Note that the oven combo and car chargers get multiplied by 0.4 (or at least, the portion of them that exceeds 8kW). This accounts for the fact that you're unlikely to use everything at the same time.

Yes, I wasn't saying that's how I'd do a load calc.

There are two different ways to do a load calc, and I'm too lazy to look for them right now. From memory, your load calc seems simpler.

A thumbnail, assuming 1000 sq ft, two small appliance circuits, two laundry circuits, a dishwasher and disposal, 6000w of cooling, 8000w of oven, totally ignoring the cooktop, seems to come up to 105amps with no EV charging whatsoever at least according to a a calculator I found online that seems to mimic your suggested load calculation fairly well.

 

[ink124]

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.

That’s correct, overheard service. Had it not been overhead, it wouldn’t have been something I’d even consider.