I live in a condo. The main breaker is only 70A. Now what?

[andy92782]

Hey all,

New guy here. I take delivery of my Model 3 in about a week.

I live in an attached townhome. I have my own, private attached two car garage. I was gearing up to have a NEMA 14-50 outlet installed but unfortunately I discovered the main breaker feeding my unit is only 70A. Other than a central HVAC system (240V/30A for the compressor), all the appliances are gas and the remaining breakers are the usual assortment of 15A and 20A circuits for lights/plugs, garbage disposal, dishwasher, forced air unit, etc. What is the largest circuit that can be added to my unit's panel given the 70A maximum? 240V/30A? 240V/20A? Nothing at all? Am I screwed?

The main breaker is located on a shared panel on the exterior of the building. My own unit has its own sub-panel located in the garage just a few feed away from where I was hoping to have the 240V outlet installed. I'm assuming at this point it would take an act of God to upgrade the main breaker and/or panel plus rewire the unit to bring larger wire into my garage (HOA approvals, building codes, whatever...).

I'm in the process of getting quotes from electricians but trying to get an idea first...

Thanks!

 

[Krash]

Do you have empty breaker circuit spots? You can put more than 70A of circuits in. Electricians doing the load analysis will consider things like time of day usage when they calculate loads, so if your AC runs during the day and you charge your car at night that definitely works in your favor.

 

[ItsNotAboutTheMoney]

IANAE

If you want 240V charging, maybe you could ask about and look into smart power options. I'd bet that overnight you'd have plenty of power available, even if calculations say anything.

 

[andy92782]

Here's a shot of the existing panel. It's completely full but I know they make replacement quad breakers that could take the space of the existing 240V/30A breaker used by the AC. The only question is... How much juice can I squeeze?

(I'm hoping I can still get 30A out of this - that would allow me to use the Gen2 Mobile

cable with a NEMA 14-30 plug)

 

[NathanielHrnblwr]

IANAE, but that looks like a subpanel. There should be a panel with a meter near it with a service breaker in it that feeds this one. Post a pic of that panel.

 

[andy92782]

IANAE, but that looks like a subpanel. There should be a panel with a meter near it with a service breaker in it that feeds this one. Post a pic of that panel.

Here you go.. (each of the main breakers underneath the four individual meters are 70A). The overall panel has a 400A rating.

 

[Derek Kessler]

All else fails, unless you need hundreds of miles a day, you can get by charging off of 120V. I did it for 6 months with my S and only twice did I have to resort to the local Supercharger to get a full charge before departing the city. Just gotta remember to plug in every time you come home.

 

[P85_DA]

You have a challenger panel known for overheating etc ..I would replace panel first ... @eprosenx

 

[cpa]

If your garage has 20A breakers, you can purchase Tesla's 20A adapter to charge 1/3 faster than 15A. You'd be pulling 16(120) or 1,920 watts. An overnight charge (11 hours, say) will add over 21kWh. With the 3's slightly better efficiency, that should translate to about 85-95 miles of range per night. Obviously, more miles if you can plug in 13-15 hours, depending upon your schedule and activities.

 

[P85_DA]

If your garage has 20A breakers, you can purchase Tesla's 20A adapter to charge 1/3 faster than 15A. You'd be pulling 16(120) or 1,920 watts. An overnight charge (11 hours, say) will add over 21kWh. With the 3's slightly better efficiency, that should translate to about 85-95 miles of range per night. Obviously, more miles if you can plug in 13-15 hours, depending upon your schedule and activities.

Personally I wouldn’t do anything with that sub panel ...OP there is plenty of documentation on failures of Challenger , FPE and Zinsco panels .. that would need to be addressed before adding load ...my $.02 cents

 

[SSedan]

There is a wide selection of adapters for the UMC2 see which one the electrician says you have capacity for.

Could throw a hail Mary and talk to the condo board about replacing the crappy breaker boxes. Might agravate the neighbors though or maybe others are considering EVs and there could be cost savings in addressing all at once.

 

[jimmyz80]

How many square feet is your townhome? There are a couple different ways to do the load calculation, but they all require your square footage. I suspect unless you do a ton of driving, you'd be plenty happy with even a 240V 20A NEMA 6-20 outlet or something along those lines. That's a weird breaker panel though, since it seems like the 240V breaker takes up the space of four 120V breakers instead of just two of them.

Depending on the wall, it looks like it may not be too huge of a job to rip that panel out and put a newer, and larger one in its place.

*EDIT* Would also be curious what the specification plate on the HVAC unit shows. I'm sort of scratching my head since I did a rough calculation using the full 30A for HVAC, and assumed even a small 1,500 square foot place, and I'm coming up with the panel being overloaded even without an EVSE being added. I'm not a professional at this though.

 

[P85_DA]

OP you prob need
1) HOA agree to update ur main breaker to 100a seems like main panel has capacity

2) get rid of that bad challenger subpanel

3) prob go with 240 30a setup

4) or since ur in Socal use superchargers

 

[andy92782]

It's a 1300sf townhome in Orange County, CA, built in 1989.

No way I'm getting the HOA involved with this. In fact, they recently published a list of rules/guidelines for installing rooftop solar that's so draconian nobody in their right mind will ever attempt to install anything.

Update: One electrician who originally quoted me on a 14-50 now says a 14-30 outlet with a 30A breaker is do-able. According to Tesla, this is good for 22 miles of range per hour when using the UMC2 and 14-30 adapter. It should be more than sufficient for my daily driving needs. I'm just bummed I'm not able to max this out with something like a 40A JuiceBox running off a 14-50 (50A circuit).

 

[P85_DA]

It's a 1300sf townhome in Orange County, CA, built in 1989.

No way I'm getting the HOA involved with this. In fact, they recently published a list of rules/guidelines for installing rooftop solar that's so draconian nobody in their right mind will ever attempt to install anything.

Update: One electrician who originally quoted me on a 14-50 now says a 14-30 outlet with a 30A breaker is do-able. According to Tesla, this is good for 22 miles of range per hour when using the UMC2 and 14-30 adapter. It should be more than sufficient for my daily driving needs. I'm just bummed I'm not able to max this out with something like a 40A JuiceBox running off a 14-50 (50A circuit).

If u have an electrician that would overload that main circuit by putting in another 30a breaker in a bad box ...good luck

 

[andy92782]

If u have an electrician that would overload that main circuit by putting in another 30a breaker in a bad box ...good luck

Just curious - are you a licensed electrician or are you speaking based on anecdotal stuff you've read on the internet?

I plan to get multiple quotes from licensed electricians and from there I'll make a decision.

 

[jimmyz80]

Have the electrician do an actual load calculation and show you the math behind it. I did a rough one and came up with requiring 75A for your existing loads, even without adding any EVSE. If your HVAC doesn't actually specify a full 30A draw, that might bring it down enough to where they thought it was okay to use a 70A feed. You may be stuck with either 120V charging on an existing circuit, or using an electrician who's ignoring the electrical code.

 

[P85_DA]

I have a general contractor license in California and own multiple buildings I know enough about electricity that I wouldn’t allow this in any of my properties ..as a matter of fact I’m curious why your HOA would allow this without permit as that wouldn’t pass a permit and not worth the personal liability you would be creating with unsafe condition

 

[andy92782]

*EDIT* Would also be curious what the specification plate on the HVAC unit shows. I'm sort of scratching my head since I did a rough calculation using the full 30A for HVAC, and assumed even a small 1,500 square foot place, and I'm coming up with the panel being overloaded even without an EVSE being added. I'm not a professional at this though.

The A/C is made by a company called Tempstar. The outdoor compressor model is CA3036VKA1. It was manufactured in 1989 and the panel says it requires a minimum 24A draw with a maximum recommended breaker of 40A. I've toyed with the idea of replacing the system but even after almost 30 years, it still works fine. The climate here is pretty mild and it really hasn't been used much over the years.

The clothes dryer and range are both gas. Electric is not an option for either as there are no 240V outlets.

 

[jimmyz80]

The A/C is made by a company called Tempstar. The outdoor compressor model is CA3036VKA1. It was manufactured in 1989 and the panel says it requires a minimum 24A draw with a maximum recommended breaker of 40A. I've toyed with the idea of replacing the system but even after almost 30 years, it still works fine. The climate here is pretty mild and it really hasn't been used much over the years.

The clothes dryer and range are both gas. Electric is not an option for either as there are no 240V outlets.

So if I plug in 24A for HVAC, I get a total required service of 69 amps. Unfortunately it looks like the current panel and feeder circuit are barely adequate for the existing loads. There may be some other small headroom available if your garbage disposal, dishwasher, and microwave pull less than mine do (what I used for the calc). But in any case it's on the ragged edge, and as others have said, be careful what you let an electrician sign you up for...