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Getting panel ready for Tesla site visit

SoCalSteve

Member
Jul 19, 2020
30
6
Irvine
Hello,

Tesla is going to be doing a site visit next week. I have a 200A panel but all the slots were taken so I moved 4 circuits to tandem breakers in order to free up 2 slots for the solar install ; no powerwall. I have a center fed panel, so I'm assuming they will want to install the 2 pole breaker at the bottom of the panel? I made sure the 2 freed up slots are at the bottom of the panel. Its a 14 panel system (4.76KW) if that matters.

Also, while I'm doing this work, I'm debating installing a 100 A subpanel and moving two more circuits (EV charger and a GFCI circuit) over to the subpanel to free up some more room. Any reason I should hold off on this till after the solar install? Subpanel install should be pretty straightforward, but now I'm paranoid about Tesla complaining about something and asking for extra $$$ for electrical work.
 

mnsweeps

Member
Aug 3, 2019
555
141
Los Angeles
SoCalSteve when did you order? I see you are in Irvine. I am in Santa Clarita Valley :) When my advisor called yesterday he mentioned Tesla mostly stopped onsite surveys as they found 92% of the cases don't need them. He said mine is in permitting stage as I had ordered on July 28.
 

SoCalSteve

Member
Jul 19, 2020
30
6
Irvine
Hi mnsweeps,

I ordered on July 20th. Got the initial layout within 2 days, but they didn't take into account of increasing the number of panels which I made by calling in right after I ordered. It looks like my designer was out of office till yesterday so that might part of the delay.

As far as the onsite visit, it looks like that was needed because of permitting in my jursidiction? At least according to the Tesla phone rep. I hear permitting is pretty fast in my city so let's see what happens!
 

SoCal Dave

Member
Jul 30, 2020
421
317
California
For my install, they added the 2 pole 60A, added the 15A Power Blaster Breaker, and downsized my 200A main to a 175A.

Since you are going with a 4.7kW system, they should be able to leave your main as a 200A.

If you do install a subpanel, you might want to consider a 200A panel fed by a 100A breaker and 100A wire. The price difference between an indoor 200A subpanel vs 100A is about $30 and it has a lot more breaker positions. That is what the 100A breaker is doing in the upper left of my panel, feeding a 200A subpanel I installed on the inside of my garage.

20200805_090330.jpg
 

SoCal Dave

Member
Jul 30, 2020
421
317
California
Also, my installer said you can request the installer walk the job with you ahead of time. I wish I would have known that as I would have probably made some adjustments.
 
Last edited:

SoCalSteve

Member
Jul 19, 2020
30
6
Irvine
Hi SoCal Dave,

Thanks again for your help. Your replies and recent thread have been a great help! I definitely owe you a beer! :)

Good point on the using a 200A panel as the 100A sub. I'll definitely consider that. The 125A sub that I just bought has 6 breaker positions (12 circuits with tandems). I was going to run 2 gauge wire for future proofing. It's quite a small run through a close nipple in the back of main panel. Did they charge you extra to derate your panel?

Did they mention how you can request the installer to walk through ahead of time? I'm assuming you have to do it with the scheduler after you get an install day.
 

SoCal Dave

Member
Jul 30, 2020
421
317
California
Hi SoCal Dave,

Thanks again for your help. Your replies and recent thread have been a great help! I definitely owe you a beer! :)

Good point on the using a 200A panel as the 100A sub. I'll definitely consider that. The 125A sub that I just bought has 6 breaker positions (12 circuits with tandems). I was going to run 2 gauge wire for future proofing. It's quite a small run through a close nipple in the back of main panel. Did they charge you extra to derate your panel?

Did they mention how you can request the installer to walk through ahead of time? I'm assuming you have to do it with the scheduler after you get an install day.

My 30 space subpanel laughs at that 6 space subpanel. ;)

This is the subpanel I installed. I did the same thing by using a 2" chase nipple. Going larger is fine, just make sure the wire will fit into the breaker you are using on your main panel.

Square D Homeline 225 Amp 30-Space 60-Circuit Indoor Main Lug Plug-On Neutral Load Center with Cover, Ground Bar - Value Pack-HOM3060L225PGCVP - The Home Depot

No charge to derate my panel. He took my 200A breaker so Tesla actually made a few dollars on the deal.

Not sure the process to request the installer walk through. Probably waiting for your job to be scheduled is good so they know which crew will be working on it.
 

SoCalSteve

Member
Jul 19, 2020
30
6
Irvine
Whoa, I'm glad I asked. I googled around and it looks like it's needed to monitoring usage data? I don't have a powerwall, will this be required to have monitoring? I see little mention of it on the forums. Thanks.
 

SoCal Dave

Member
Jul 30, 2020
421
317
California
Whoa, I'm glad I asked. I googled around and it looks like it's needed to monitoring usage data? I don't have a powerwall, will this be required to have monitoring? I see little mention of it on the forums. Thanks.

The way I think this works is this measures the in/out power coming from the power company. The inverter knows the power being generated from the solar panel. From these measurements your usage can be inferred.

If you don't have this, then all you could see in the app is how much power your solar panels are generating. You wouldn't know how much you are pulling from the grid, selling to the grid, or how much electricity your house is using.
 

SoCal Dave

Member
Jul 30, 2020
421
317
California
Any Idea on what Tesla charges to do a Electric panel upgrade?

Not sure on Tesla pricing, but panel upgrades can vary by a lot. For example, going from 60A to 100A is significantly cheaper than going from 200A to 400A. Also, if your meter is in a bad location like you can't read it from the fence, the electric company will often require you to relocate it if you want to upgrade the panel. Number of circuits is a factor as well.

Do you know you need an upgrade for solar? Since solar is typically a swap for existing usage, a panel upgrade shouldn't normally be required. Unless you are adding car charging stations or some other additional usage.
 

jdmte30

Member
Aug 5, 2020
37
6
SoCal
Not sure on Tesla pricing, but panel upgrades can vary by a lot. For example, going from 60A to 100A is significantly cheaper than going from 200A to 400A. Also, if your meter is in a bad location like you can't read it from the fence, the electric company will often require you to relocate it if you want to upgrade the panel. Number of circuits is a factor as well.

Do you know you need an upgrade for solar? Since solar is typically a swap for existing usage, a panel upgrade shouldn't normally be required. Unless you are adding car charging stations or some other additional usage.


Thanks for the Reply SoCal Dave, He is a picture of my dated panel box.... Original to the home since 1979
 

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MIT_S60

Active Member
Nov 23, 2016
1,052
909
Orange County, CA
Any Idea on what Tesla charges to do a Electric panel upgrade?
I've also been wondering as well. I'll need to upgrade 100 to 200amp panel and likely add a sub panel, but the utility company told me I don't need to move the meter. I have two Founder's Series Powerwall 2's sitting in my garage, but Tesla won't install them alone, and the certified installers quotes were all much higher than anticipated (nothing special about the install, just going in the garage right next to the panel). I'm thinking it's going to end up costing me nearly the same after tax credits to order the small Tesla solar system and have Tesla install the Powerwalls at the same time, but I have no idea how much Tesla charges for a panel upgrade.
 

SoCal Dave

Member
Jul 30, 2020
421
317
California
My meter is right next to my panel and is easy to read, it's also a newer WIFI meter I think.View attachment 572956

Wow, that's a full panel. Spa, AC, electric dryer, stove and oven. Do you ever trip your main breaker?

Panel Upgrade

There are a couple ways to determine load calculations to see if you need an upgrade. First is you convert each breaker to watts add them up at 80% their value. Converting back to amps will tell you what your panel/main breaker needs to be sized to. With all your larger breakers you are easily exceeding 125A, so this approach requires you to upgrade.

The other option is to have a year of usage and finding your peak usage during the period (30 days is acceptable if a year isn't available) Then take the maximum value and add 25%. This would give you the panel/main breaker size required. There are meters designed to do this, but your electric company website can probably help you approximate this (an inspector would not accept this method if they question your panel load).

Here is my graph from SCE for a warm day over the weekend. The peak I used was 6kWh or 6,000Wh. For this approximation, I assume this is equivalent to 6,000W at any given moment during that hour. 6,000W/240V = 25A. Adding 25% means my main breaker/panel needs to only be larger than 31.25A if this is my peak usage for the month.

upload_2020-8-5_17-6-52.png


Sub Panel

Your Zinsco panel is obviously full. They do make slim breakers, but Zinsco panels do not have much room for wires. I bet if you open your inner cover the panel it will be crammed full. So you might consider adding a sub panel if you don't require a panel upgrade.

Solar Considerations

There is one other potential gotcha when it comes to solar. The solar breaker + your main breaker cannot exceed 120% of your panel rating. Assuming your panel is a 125A panel, that means you are allowed to go to 150A. So the breaker they install for solar cannot exceed 25A.

If they do need to install a breaker larger than 25A, either your panel needs to be replaced or your main breaker downsized. For my install, they downsized my 200A breaker to a 175A as that is ~$100 for a main breaker instead of thousands for a 400A upgrade. Considering my peak usage is significantly below 175A, that is not going to be a problem for me.
 

jdmte30

Member
Aug 5, 2020
37
6
SoCal
Wow, that's a full panel. Spa, AC, electric dryer, stove and oven. Do you ever trip your main breaker?

Panel Upgrade

There are a couple ways to determine load calculations to see if you need an upgrade. First is you convert each breaker to watts add them up at 80% their value. Converting back to amps will tell you what your panel/main breaker needs to be sized to. With all your larger breakers you are easily exceeding 125A, so this approach requires you to upgrade.

The other option is to have a year of usage and finding your peak usage during the period (30 days is acceptable if a year isn't available) Then take the maximum value and add 25%. This would give you the panel/main breaker size required. There are meters designed to do this, but your electric company website can probably help you approximate this (an inspector would not accept this method if they question your panel load).

Here is my graph from SCE for a warm day over the weekend. The peak I used was 6kWh or 6,000Wh. For this approximation, I assume this is equivalent to 6,000W at any given moment during that hour. 6,000W/240V = 25A. Adding 25% means my main breaker/panel needs to only be larger than 31.25A if this is my peak usage for the month.

View attachment 572970

Sub Panel

Your Zinsco panel is obviously full. They do make slim breakers, but Zinsco panels do not have much room for wires. I bet if you open your inner cover the panel it will be crammed full. So you might consider adding a sub panel if you don't require a panel upgrade.

Solar Considerations

There is one other potential gotcha when it comes to solar. The solar breaker + your main breaker cannot exceed 120% of your panel rating. Assuming your panel is a 125A panel, that means you are allowed to go to 150A. So the breaker they install for solar cannot exceed 25A.

If they do need to install a breaker larger than 25A, either your panel needs to be replaced or your main breaker downsized. For my install, they downsized my 200A breaker to a 175A as that is ~$100 for a main breaker instead of thousands for a 400A upgrade. Considering my peak usage is significantly below 175A, that is not going to be a problem for me.

Thanks again Socal Dave for the reply, The only breaker that trips sometimes is my stove top, it's an induction cook top and can draw extra power if we cook more than 3 items on the stove at full power. The Spa never tripped and breakers.


upload_2020-8-5_18-13-26.png
 

sleevemedia

Member
Jul 1, 2020
57
41
Orlando
Any Idea on what Tesla charges to do a Electric panel upgrade?

When I asked them this question, they said they get three bids and show you the best offer. They leave/suspend/delay the job and wait for the panel upgrade to be completed. The upgrade typically requires another electric permit because the bidder is arms' length to Tesla Energy Operations. In some places, Tesla needs to close its permit to allow the other to open. There's a note on my permit that says any work other than line side tap, load side tap, and backfeed requires a separate permit. In my county, they can run concurrent. Fortunately, I don't need a panel upgrade, but...

I did way too much reading here and freaked out about situations some of us have faced, combined with my state's regulations and my utility's interconnect requirements. I figured, well, heck, all my luck I'm going to need a panel, service lateral, and transformer upgrade.

Then my permit application got approved by the county. Then I could download the three-line diagram. Then I said oh, you crafty geeks, look how you got around all this nonsense I was afraid of. Main thing that came from that is I learned I have a properly sized service cable from the utility for what I want to do even though my service disconnect is rated much lower than what the cable can carry by Code.

What I've gained from this is if you do the self-assessment steps and they proceed to permitting, the engineering team has enough information to submit without requiring a site survey. If they need a survey, that forecasts work out of the scope of the flat rate t-shirt size quotes.
 
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Reactions: Ormond

jdmte30

Member
Aug 5, 2020
37
6
SoCal
When I asked them this question, they said they get three bids and show you the best offer. They leave/suspend/delay the job and wait for the panel upgrade to be completed. The upgrade typically requires another electric permit because the bidder is arms' length to Tesla Energy Operations. In some places, Tesla needs to close its permit to allow the other to open. There's a note on my permit that says any work other than line side tap, load side tap, and backfeed requires a separate permit. In my county, they can run concurrent. Fortunately, I don't need a panel upgrade, but...

I did way too much reading here and freaked out about situations some of us have faced, combined with my state's regulations and my utility's interconnect requirements. I figured, well, heck, all my luck I'm going to need a panel, service lateral, and transformer upgrade.

Then my permit application got approved by the county. Then I could download the three-line diagram. Then I said oh, you crafty geeks, look how you got around all this nonsense I was afraid of. Main thing that came from that is I learned I have a properly sized service cable from the utility for what I want to do even though my service disconnect is rated much lower than what the cable can carry by Code.

What I've gained from this is if you do the self-assessment steps and they proceed to permitting, the engineering team has enough information to submit without requiring a site survey. If they need a survey, that forecasts work out of the scope of the flat rate t-shirt size quotes.
Thanks for the reply.
 

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