Changing a breaker from 50 to 60 amps, is it worth it?

[Falkirk]

I have 200 amps coming to the house, 150 for the home and 50 for my wall connector. This is my first winter with the 3 and noticing it charges slower but still plenty at ~60km/h @10kW (summer was ~70km/h).

I've been checking prices and it's not a big deal to buy a 60 amp breaker, then I could charge at 48 amps to the car. I figure might as well take advantage of the setup.

Any concerns or things I should be aware of? I'm planning on doing it myself with my dad who's done this before.

Thanks,
David

 

[electracity]

Breaker is sized to wire size. You can't safely change a breaker without knowing the wire gauge in the circuit.

Also, changing the breaker will not necessarily improve your model 3 car charger speed.

 

[MrYenko]

To expound on this a bit, the breaker exists to make sure that in case of an overcurrent situation, the breaker will trip open before the conductor gets hot enough to melt/start a fire. If the conductor was sized to support a 60a breaker, you can absolutely swap breakers, and enjoy the higher capacity circuit. This is almost never done in new-construction situations, since heavier conductor is more expensive, which gets pricey quick when you multiply it by however many homes are being built simultaneously. If you had an electrician install the circuit specifically for EV charging, then there is a (small) chance that he may have upsized the conductor to future-proof you.

However, in the very likely event that the conductor was sized to support the 50a breaker, and you put a 60a breaker into the circuit, you're creating a situation where the wall connector could plausibly draw enough current to (best case) damage the wiring or (worst case) start a fire.

Conductor is sized according to a few things, including length of conductor, whether it is contained in conduit, etc etc, so its really not possible to tell you if you're good to go without putting eyes and hands on it. As always when dealing with 240vac, CALL AN ELECTRICIAN.

 

[derotam]

Sorry, I am going to nitpick a bit....it is more accurate to just say you have 200A service, with a 50A breaker for your wall connector. You do NOT have 50A dedicated for the wall connector. That 50A is just part of the 200A allowance

I also agree with electracity about verifying the wire size. It is unlikely that your wire size would support a larger breaker...but maybe you'll get lucky.

 

[eprosenx]

I have 200 amps coming to the house, 150 for the home and 50 for my wall connector. This is my first winter with the 3 and noticing it charges slower but still plenty at ~60km/h @10kW (summer was ~70km/h).

I've been checking prices and it's not a big deal to buy a 60 amp breaker, then I could charge at 48 amps to the car. I figure might as well take advantage of the setup.

Any concerns or things I should be aware of? I'm planning on doing it myself with my dad who's done this before.

Thanks,
David

What kind of wire is used? Romex (NM cable) or is it THHN in conduit?

What gauge is it? (Copper I am assuming)

You are referring to a hard wired wall connector and not just a plugged in UMC? (Just verifying)

Most likely you are on 6awg copper romex and that is only good to 55 amps. So you can’t set the wall connector to 60 amps (48a continuous) even if you had a 60a breaker.

If it happens to be THHN #6 awg all the way in conduit then you can swap to a 60a breaker and change the wall connector rotary dial up to 60/48 (assuming this does not push you over the lord limit on your 200a). This is what I have (6awg in conduit on a 60a breaker for my wall connector)

As others have mentioned, you can’t just go upsizing the breaker unless the wire happens to be rated for it (which begs the question why the electrician did not do 60 in the first place).

Note that while distance can be a factor (due to voltage drop), it is not actually required by code to be factored in. Most residential installations don’t need wire upsizing due to distance.

Things that do factor in are ambient temperatures the wire is exposed to and any other deration reason like # of conductors in a conduit, etc...

 

[ratsbew]

Trip the main breaker, figure out what size wire you have and then decide from there.

 

[ecarfan]

Any concerns or things I should be aware of? I'm planning on doing it myself with my dad who's done this before.

Hire a qualified electrician. You have received very good advice in the posts so far. Why risk a fire that could burn your house/garage down to get 8 more amps of charging power? If your wiring isn’t the correct size for a 60A breaker (in your case 48A that the car could attempt to draw) the consequences could be very serious.

 

[eprosenx]

Hire a qualified electrician. You have received very good advice in the posts so far. Why risk a fire that could burn your house/garage down to get 8 more amps of charging power? If your wiring isn’t the correct size for a 60A breaker (in your case 48A that the car could attempt to draw) the consequences could be very serious.

I generally disagree with the push to just tell folks to "call an electrician". People come to these forums to ask questions and learn. I feel we should answer those questions as completely and fully as we can (but also to provide the right cautions). Some homeowners are more than capable of doing high quality safe work on their own after the appropriate research. Others probably should not (but it is not really something we can evaluate through a couple of forum posts).

Even if we advise someone to seek professional help, it is likely useful for us to help educate them on what to expect so that (a.) They don't get taken advantage of, and (b.) They may be able to catch potential mistakes made by "professionals" (we see that all the time in the forums here).

If @Falkirk does have sufficient ampacity wire installed, then the task of swapping out a breaker is a pretty easy one. It sounds like he has some support from his father who has some level of knowledge.

Of course I would always recommend that he get this permitted and inspected which provides another level of safety margin.

 

[iluvmacs]

This is my first winter with the 3 and noticing it charges slower but still plenty at ~60km/h @10kW (summer was ~70km/h).

Actually, it's charging at the same rate (40A / 10KW). The efficiency of your car is just lower when cold, so the km/hr estimate goes down.
Well I guess to be completely true, it may spend some time charging at lower power levels when very cold, but that won't change based on the power feed.

 

[eprosenx]

Actually, it's charging at the same rate (40A / 10KW). The efficiency of your car is just lower when cold, so the km/hr estimate goes down.
Well I guess to be completely true, it may spend some time charging at lower power levels when very cold, but that won't change based on the power feed.

Excellent points! I should also add though that if the battery heater (aka the motor in the case of the Model 3) has to run then it actually would charge slower since energy would be lost to heat the battery rather than charge it.

 

[Falkirk]

Thanks everyone for the education and questions to ask. I'm talking to the installer about what wire gauge he used before proceeding for sure.

It's a very short wire about 1m in a rigid conduit, I got lucky and the main panel is in the garage in the perfect spot after putting solar in they had to do that anyways.

I agree the charging is the same rate as well, it's just less effective in the winter I'm learning.

I'm happy to leave it as-is if not safe to easily just change the breaker, but if I can I'd love to charge at the highest rate possible.

I'll keep you posted!

 

[Big Earl]

Thanks everyone for the education and questions to ask. I'm talking to the installer about what wire gauge he used before proceeding for sure.

It's a very short wire about 1m in a rigid conduit, I got lucky and the main panel is in the garage in the perfect spot after putting solar in they had to do that anyways.

I agree the charging is the same rate as well, it's just less effective in the winter I'm learning.

I'm happy to leave it as-is if not safe to easily just change the breaker, but if I can I'd love to charge at the highest rate possible.

I'll keep you posted!

If it's only a 1 meter run, it shouldn't cost very much to upgrade the wires to a larger gauge to support 60 amps.

 

[Falkirk]

I heard back from my electrician who did the install. He says the wire used is good for 60A as well so it does seem it's a simple breaker swap. He suggested it was that simple as well, able to do it any night on the way to his home even!

I'll still go over it with my dad and see if it's something we'll do ourselves.

 

[Kirby64]

I heard back from my electrician who did the install. He says the wire used is good for 60A as well so it does seem it's a simple breaker swap. He suggested it was that simple as well, able to do it any night on the way to his home even!

I'll still go over it with my dad and see if it's something we'll do ourselves.

If the wire is rated for it, swap it over. Honestly not sure why he wouldn't install a 60A in the first place (unless you told him to only install a 50A...). Might as well get the most out of it right?

 

[woodguyatl]

If the wire is rated for it, swap it over. Honestly not sure why he wouldn't install a 60A in the first place (unless you told him to only install a 50A...). Might as well get the most out of it right?

I suspect the electrician was used to putting in 14-50's for EV's and assumed the wall unit was 50 amp.

 

[eprosenx]

Thanks everyone for the education and questions to ask. I'm talking to the installer about what wire gauge he used before proceeding for sure.

It's a very short wire about 1m in a rigid conduit, I got lucky and the main panel is in the garage in the perfect spot after putting solar in they had to do that anyways.

I agree the charging is the same rate as well, it's just less effective in the winter I'm learning.

I'm happy to leave it as-is if not safe to easily just change the breaker, but if I can I'd love to charge at the highest rate possible.

I'll keep you posted!

Oh nice! That sounds easy. So a few things:

Are you sure the conduit is "rigid"? That is not very common for interior wiring. It is more likely "EMT". Can you send pictures of it (including of your panel, panel schedule, etc...)? Either way is fine, but I just want to verify.

Since you say it is in conduit, then your electrician could have run 8 AWG for 50 amps since THHN wire in conduit can be used at the 75c rating.

If it already is 6 AWG copper in that conduit then you can simply swap to the 60a breaker as discussed and reset the rotary dial in the Wall Connector to match.

Note though that you technically need to run a load calculation to ensure your service itself has sufficient capacity to handle the increase from 40 amps continuous to 48 amps continuous.

I know I for sure would be doing what you describe if it is really that simple! A breaker is like $10. The wire will be cheap since it is so short.. I like my 48 amp charging rate!

 

[Falkirk]

Just took these. The conduit does mention 75c dry.

Thanks for the insight.

 

[eprosenx]

Just took these. The conduit does mention 75c dry.

Thanks for the insight.

Ok perfect! Thanks!

So that is kind of a hilarious setup. Only a single breaker in that panel (nice new beautiful high quality panel though!). Now I am curious how that panel is fed... Is it tapped off your main service feed? Or is it downstream of your main panel? And is your main service 200a or 320/400a? A picture of your meter base and meter would answer that. Oh actually, maybe this is inline with your main panel? So 200a feed from the meter base into this panel and then 150a subfeed to the house and 50a to the car? Is there a 200a breaker or disconnect out on the outside meter base?

Interesting that the electrician used 3/4in LFMC conduit - not what I was expecting, but totally fine - makes sense for that mounting setup. Zero issues with using the 75c wire rating. So as long as the wire in that conduit is at least 6awg you are golden on a 60a breaker.

We still have to worry about load calculations here, but there is a high likelihood that going from 40 amps continuous to 48 amps continuous will be no issue. ;-) The piece I am now wondering about is if you have a 200a main breaker upstream of this panel. If not, then both the 150a breaker and the EV breaker would be considered "service disconnects" and need to be labeled as such. There would be nothing stopping the house from drawing 150a and the car drawing 60a which could overload the 200a feed. Now I think code allows for this as long as the load calculations say it is ok, but it makes me pay attention to the load calcs a lot more since there is not an overcurrent device as a backup.

 

[Falkirk]

I didn't take any more pictures yet but it is 200A to the household. I installed solar and that required moving the service to a new wall outside, digging in the middle of the winter etc! It has a cut off outside (maybe that's just related to solar, I'm not an expert about this stuff).

The empty panel with just 2 breakers is now my main panel in the garage, the existing panel with tons of breakers for the house is a sub-panel now.

 

[Falkirk]

So after quite some time I finally did buy the breaker and install it. There were no issues, took maybe 5 mins to swap the breaker and only later did I realize I also had a make a change to the wall connector to use the higher amps. That went well too and I'm now able to charge at 12kW instead of 10. Costs were just for the breaker at about $40 and time, so I'm happy.

Thanks for the feedback before doing this guys!