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Charging Options with Full Panel

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Hello all,

In advance, I have no clue about electrical setup and am just taking the word of any electrician I speak with, but the issue is I've been getting conflicting answers.

I have a question about my home setup. I have solar panels installed and according to an electrician I spoke with, he said that my panel is completely full and that I have to have a subpanel installed to take advantage of the Wall Connector's max 48 amps. He also said I need to provide a city permit or else they will do it themselves and charge me $600 in addition to the installation costs.

Another electrician said that a subpanel is not necessary and that he will install a 2 pole breaker and pull amp readings on the 15A lighting circuits and pair some up to make space for the 2 pole breaker. He said with this setup, he said the wall connector will only be able to max out at 40 amps. He assured me that this should work fine, but we didn't mention anything about whether the setup would be up to electrical code and he mentioned that pulling a permit with the city is not necessary.

The second electrician is obviously quoting a lot lower price than the first electrician.

Does it sound like the second electrician should be good to go with? Any advantages or disadvantages with going with a subpanel install?

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If you are planning to remain in the house for ~5 years or longer then the sub panel would provide the better solution. You could add a second Wall Connector or other EV charging equipment in the future.

A 240V 40 amp circuit enables charging at 32 amps (EV charging is always limited to a maximum of 80% of the circuit rating.) This would enable charging at up to 29 miles added per hour to the Tesla Model Y's battery (I charge at 32 amps and get between 25 and 26 miles per hour while charging.)

If you are on a time of use (TOU) rate plan it may only offer the lowest per kWh rate between midnight and 0600. In that case charging at 48 amps would be a benefit, complete charging in less time (this would require a 60 amp charging circuit, in your case the electrician stated that you would need the sub panel.) Charging at 48 amps can enable adding up to ~40 miles per hour. The Tesla vehicle will charge faster at 48 amps than 32 amps but both will get the job done in a reasonable time. Most drivers commute, drive ~30 miles per day. If you are driving twice that or more then charging at 48 amps would help ensure that you can complete daily charging of one or even two EVs in the time alloted to the TOU off-peak rate window.
 
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If you are on a time of use (TOU) rate plan it may only offer the lowest per kWh rate between midnight and 0600. In that case charging at 48 amps would be a benefit, complete charging in less time (this would require a 60 amp charging circuit, in your case the electrician stated that you would need the sub panel.) Charging at 48 amps can enable adding up to ~40 miles per hour. The Tesla vehicle will charge faster at 48 amps than 32 amps but both will get the job done in a reasonable time. Most drivers commute, drive ~30 miles per day. If you are driving twice that or more then charging at 48 amps would help ensure that you can complete daily charging of one or even two EVs in the time alloted to the TOU off-peak rate window.

I am currently in a tiered plan. I would have the option of converting to a TOU 4-9 or TOU Prime (special for EV owners) with Southern CA Edison.

I will collect stats with our usage and see what works better with our needs.


So it seems like if I didn't want to have a sub panel installed, then the second electrician's method will be good enough?

The biggest thing I'm worried about is making sure that code is met and that everything is safe.
 
I am currently in a tiered plan. I would have the option of converting to a TOU 4-9 or TOU Prime (special for EV owners) with Southern CA Edison.

I will collect stats with our usage and see what works better with our needs.


So it seems like if I didn't want to have a sub panel installed, then the second electrician's method will be good enough?

The biggest thing I'm worried about is making sure that code is met and that everything is safe.
It is common to double up using slim 15A, 20A single pole breakers. This frees up space, does not by this action overload the panel. The electrician should be able to calculate based on the current circuits whether you can add a 40 amp (or 50 amp) circuit but not any more than that to the existing panel or service.

Any licensed electrician should know whether a permit is required for the work in your area, i.e. installing a new 40 amp or 50 amp circuit maybe not, installing a sub panel, yes a permit would be required.

Even the often overlooked 240V/20A EV charging circuit can add 12 to 14 miles of range to the Tesla vehicle per hour. If you only drive the average daily commuting distance of 30 miles per day charging at 16 amps (following the 80% of circuit maximum charging rule) it would take ~2.5 hours to replenish the battery each evening. (You almost never charge above 90% with the Tesla Supercharger network there to use on road trips. For daily use Tesla recommends keeping the Tesla vehicle charged between 50% and 90% with most Tesla owners probably charging to 70% or 80%. When you arrive home at the end of your day you only need to charge long enough to bring the Tesla battery pack back to your preferred maximum charge level such as 80%. (Charging at 240V and 16 amps adds ~5% per hour to the battery; charging at 240V and 32 amps adds ~10% per hour while charging. Charging at 240V and 48 amps (the maximum for the Tesla Long Range or Performance Model Y using Level 2 charging) would add ~15% per hour while charging.)
 
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making sure that code is met and that everything is safe.
A permit from the city comes with an inspection to keep the electrician to code. I don't know the technical answer to your question (@jcanoe I think has a vslid point about doubling up) but would go with a sub panel. Yours is full and working good. Consolidating and charging at lower amperage is limiting and tends to just lock the can down the road. For me I would go with a licensed electrician that would pull the permit for you. I would put in a dedicated EV panel that has capacity and room for more EVs. This will cost more but you will have great piece of mind, no worries of overheating or limited capacity.

Your particular situation is probably playing out all over the US with EV use. Hopefully one sees your post.
 
It is common to double up using slim 15A, 20A single pole breakers. This frees up space, does not by this action overload the panel. The electrician should be able to calculate based on the current circuits whether you can add a 40 amp circuit but not any more than that to the existing panel or service.

Any licensed electrician should know whether a permit is required for the work in your area, i.e. installing a new 40 amp circuit maybe not, installing a sub panel, yes a permit would be required.
Just wanted to confirm... In my original post, I mentioned 40 amps, but I meant 40 amps for the max output. The electrician said that he would install a 50 amp circuit.
 
Just wanted to confirm... In my original post, I mentioned 40 amps, but I meant 40 amps for the max output. The electrician said that he would install a 50 amp circuit.
All is well; if your electrician has already determined that they can add a 50 amp circuit this would enable charging at 40 amps instead of 32 amps. ~25% faster than a 40 amp circuit but otherwise the same.
 
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Just so you know, the second electrician could put in a Eaton/Cutler-Hammer BQ240250 Quad Circuit Breaker or https://www.eaton.com/us/en-us/skuPage.BQC225225.html to free up spaces. The BQC240250 would just piggyback your new circuit on the 40 amp breaker spots you are currently using, while the BQC225225 would combine the 25 amp spots leaving you with two empty spots to install a conventional 50 amp duplex breaker in.

Were I doing it, I'd use the BQC225225, leading to a max load on the bus bar connection to the breaker of 50 amps, as opposed to the BQC240250 which would potentially draw 90 amps.
 
All of your 15 and 20A breakers are already tandem, where the solar is connected you have a quad breaker, it is possible to replace one of your 2 pole full size breakers to a quad style, you have 3 to choose from, the 2 ac spots and the oven one, technically you may have to do a load calculation to see if a 200A service is large enough but you will most likely want to charge in the late evenings so it would not really be a problem.

Here is an example to use in place of the oven breaker

 
It looks like a fairly small panel for a 200A service. Only 20 spots. My panel for 200A service has 40 spots. I know the option will likely cost more, but is there any reason you can't just swap the panel for a larger one? Physical restrictions? Seems like a nice 40 spot load center would allow you to switch to mostly full size breakers except for a few tandem 15A ones for lights and then you'd have more room for some full size 2 pole breakers.

Also, I could be way off base but it looks like the outer connecting plates should be removed from the two quad breakers since those circuits are not 2 pole 240V. Telephone, Dining and Master 2 all appear to be 120V circuits so don't need to be tandemed (and likely aren't on the wiring side because who has 240V lighting. It seems odd that they would even be installed since a proper single/double/single breaker wouldn't come with them to start with. And it also seems odd that the smoke (SMOG?) det circuit is 240v.
 
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It looks like a fairly small panel for a 200A service. Only 20 spots. My panel for 200A service has 40 spots. I know the option will likely cost more, but is there any reason you can't just swap the panel for a larger one? Physical restrictions? Seems like a nice 40 spot load center would allow you to switch to mostly full size breakers except for a few tandem 15A ones for lights and then you'd have more room for some full size 2 pole breakers.

Also, I could be way off base but it looks like the outer connecting plates should be removed from the two quad breakers since those circuits are not 2 pole 240V. Telephone, Dining and Master 2 all appear to be 120V circuits so don't need to be tandemed (and likely aren't on the wiring side because who has 240V lighting. It seems odd that they would even be installed since a proper single/double/single breaker wouldn't come with them to start with. And it also seems odd that the smoke (SMOG?) det circuit is 240v.
These are handle ties on two single poles and not a common trip breaker like a double pole, they place them on there when the 120v circuits share a common neutral, that way if you manually turn off one side the other circuit sharing the neutral turns off as well.