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Combination panel with gateway

dancudds

Member
Nov 1, 2019
96
26
San Francisco
Hi guys,

I've been searching this forum (and the Internet) but I cannot find an answer to this one.

I live in Marin County and after the recent PSPS with young kids and a baby, really thought I better get solar+battery backup. I have ordered the 3.8kw with powerwall from Tesla and am scheduled for an assessment next month.

A couple of years back I had our panel upgraded (inspection told me it was an old panel that could catch fire etc) to a 200amp service. The contractor put in a combination panel that is vertically fed. This was at great expense to me but I went for it to 'future-proof' being 200 amps and all.

Now I'm trying to work out how Tesla will wire the gateway without having to rip out and redo the entire main panel. Can they use the existing combination as a main panel and relocate the service/meter further up the feed to place the gateway inline? I cannot find any examples of combination panels being used without a meter but I don't see why that can't be the case.

Here's my panel Imgur the service drop wraps around my garage about 20 feet. My wife really doesn't want to have any more panels near the entrance to the home.
 

ohmman

Plaid-ish Moderator
Feb 13, 2014
10,201
18,736
North Bay, CA
They'll probably ask you to choose circuits you'd like to keep on backup, and they'll pull those circuits out of your 200A main panel into a smaller subpanel. That could theoretically be located in a less prominent spot in the home, possibly closer to your Powerwall and inverter. I can't think of a reason your combination panel would cause issues with that, but someone else here might know more.
 
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cwied

Member
Jan 13, 2015
887
643
San Mateo, CA
I wasn't even asked. They just pulled all the circuits from the main panel to a separate load panel. The only active breaker left in the main panel is the one going to the load panel.
 

dancudds

Member
Nov 1, 2019
96
26
San Francisco
Thanks for the replies. When I had my main panel swapped out they told me they couldn't move the panel location due to existing wire length etc. I don't have any large loads so I'm happy to keep all my loads behind the powerwall but I guess I'll have to ask at the home assessment.
Oh and I've been having a long back and forth with Tesla to get the $1000 wildfire discount. I signed up after Elon's tweet but before the website supported it. I guess that's par for the course dealing with Tesla support.
 

charlesj

Active Member
Oct 22, 2019
1,267
294
Monterey, CA
...
Oh and I've been having a long back and forth with Tesla to get the $1000 wildfire discount. I signed up after Elon's tweet but before the website supported it. I guess that's par for the course dealing with Tesla support.
I ordered mine after Elon gave a 10% discount on package but I was told that applies to a full system, panels and PW. I am not happy.
 

dancudds

Member
Nov 1, 2019
96
26
San Francisco
Got my assessment moved up to next week yay! I've got a few other quotes via energysage and pickmysolar. None came within $5k of Tesla albeit generally with 5kW panels vs 3.8kW.

I won't be at home during the assessment so I gave my wife a quick sketch IMG-1458
I'm hoping they can splice into the existing service drop to main panel run and add a service disconnect there.
 

davidwpb

Member
May 17, 2019
48
10
west palm beach, florida
I just had my install done in florida and it seemed that if they did yours like mine, they would just need to run power our of the panel to gateway and then pack in They basically intercepted the main wire from meter to my panel to insert the gateway. The main panel is behind the meter can. The only reason I can think of that this wouldnt work for you is if the meter is not wired to the disconnect and is connected via metal like how circuit breakers are attached to the panel. See photos and plans below.
 

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jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,854
12,581
Riverside Co. CA
Yeah I got the full system - we'll see how many hoops I have to go through to get the $1k off. Why didn't you go for the full system? Only PW?

Because @charlesj already has existing solar.

I can also confirm that I was told the 10% discount was only for solar + powerwall.

@dancudds it seems that your discount should be more than 1k if you are getting solar + powerwall... the discount was 10% not 1k according to the tweet elon stated. Are you saying that your solar + powerwall is only 10k?
 

dancudds

Member
Nov 1, 2019
96
26
San Francisco
I just had my install done in florida and it seemed that if they did yours like mine, they would just need to run power our of the panel to gateway and then pack in They basically intercepted the main wire from meter to my panel to insert the gateway. The main panel is behind the meter can. The only reason I can think of that this wouldnt work for you is if the meter is not wired to the disconnect and is connected via metal like how circuit breakers are attached to the panel. See photos and plans below.
Perhaps we're similar, although you had a physically separate meter and main panel before right? I had my assessment on Monday but didn't get many answers - apparently the design team will know more.
 

dancudds

Member
Nov 1, 2019
96
26
San Francisco
Because @charlesj already has existing solar.

I can also confirm that I was told the 10% discount was only for solar + powerwall.

@dancudds it seems that your discount should be more than 1k if you are getting solar + powerwall... the discount was 10% not 1k according to the tweet elon stated. Are you saying that your solar + powerwall is only 10k?
His tweet was "If you’re directly affected by wildfire power outages, Tesla is reducing Solar+Powerwall prices by $1000 as of today". When you order online there's no a checkbox for the $1k off gross pricing but I ordered mind post-tweet pre-website change.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,854
12,581
Riverside Co. CA
His tweet was "If you’re directly affected by wildfire power outages, Tesla is reducing Solar+Powerwall prices by $1000 as of today". When you order online there's no a checkbox for the $1k off gross pricing but I ordered mind post-tweet pre-website change.

The original quote from him was 10%. I had just decided to purchase 2 powerwalls due to the power shutdowns near the end of september. After finding out that the 10% did not apply to me, I stopped looking into it. I just did a bit of googling and see the quote from him you are talking about, which was on october 28th. On october 11th he said 10%, a snapshot of which can be seen in this article:

Tesla reduces Solar + home battery pricing following California blackouts

In any case, good luck!
 
Jun 22, 2017
527
338
Bay Area, California
Hi guys,

I've been searching this forum (and the Internet) but I cannot find an answer to this one.
Now I'm trying to work out how Tesla will wire the gateway without having to rip out and redo the entire main panel. Can they use the existing combination as a main panel and relocate the service/meter further up the feed to place the gateway inline? I cannot find any examples of combination panels being used without a meter but I don't see why that can't be the case.

Here's my panel Imgur the service drop wraps around my garage about 20 feet. My wife really doesn't want to have any more panels near the entrance to the home.
@dancudds There are plenty of folks using combination meters. The most simplistic approaches are:
1. Make cost priority over needs. Tesla finds the closest design to meet objectives independent of cost; yet there are electrical designs that require no panel upgrade ($) if you are willing to be okay with not prioritizing certain features (such as whole house backup). I have found out that "whole house backup" hiked the installation cost significantly.
2. Existing sub-panels are cost savers. This makes parsing loads easy convenient and cheaper. Typical examples are house subpanels, A/C subpanels (unlikely since you are in SF), etc. Do you have any?
3. The ultimate cost saver (I would advocate this to all), is to have the powerwall system come off a of BRANCH circuit from the service panel. ALL (?) branch circuits are capable of at least 125A of 240V (i.e. max branch breakers are sized at 125A). 125A is a lot of power. (Hint: do not backup the EV (and AC). Don't worry you can still offset those loads, just talk to electrician day-of-install... this is NOT documented in detail in their design disclosure for permits. I am satisfied with the said design. As for me, installation was the minimum charge advertised at the time... $800 and $100 for each additional powerwall. 2017 prices!
4. In panel splices are COMMON practice now to extend wire runs. Under no circumstance do you want to move the service panel unless you have money to burn. I went thru the exercise of investigating/quoting a 200A service panel swap and 400A upgrade, and abandoned 99% thru; so I understand how you do not want to redo your 200A service panel.

I hope this helps.
 
Last edited:

Vines

Active Member
Jul 20, 2018
2,078
2,495
Silicon Valley, CA
@dancudds There are plenty of folks using combination meters. The most simplistic approaches are:
1. Make cost priority over needs. Tesla finds the closest design to meet objectives independent of cost; yet there are electrical designs that require no panel upgrade ($) if you are willing to be okay with not prioritizing certain features (such as whole house backup). I have found out that "whole house backup" hiked the installation cost significantly.
2. Existing sub-panels are cost savers. This makes parsing loads easy convenient and cheaper. Typical examples are house subpanels, A/C subpanels (unlikely since you are in SF), etc. Do you have any?
3. The ultimate cost saver (I would advocate this to all), is to have the powerwall system come off a of BRANCH circuit from the service panel. ALL (?) branch circuits are capable of at least 125A of 240V (i.e. max branch breakers are sized at 125A). 125A is a lot of power. (Hint: do not backup the EV (and AC). Don't worry you can still offset those loads, just talk to electrician day-of-install... this is NOT documented in detail in their design disclosure for permits. I am satisfied with the said design. As for me, installation was the minimum charge advertised at the time... $800 and $100 for each additional powerwall. 2017 prices!
4. In panel splices are COMMON practice now to extend wire runs. Under no circumstance do you want to move the service panel unless you have money to burn. I went thru the exercise of investigating/quoting a 200A service panel swap and 400A upgrade, and abandoned 99% thru; so I understand how you do not want to redo your 200A service panel.

I hope this helps.

1. Depending on the size of the Powerwall and solar system this is true. Follow the advice of your design professional.
2. Absolutely
3. I think you mean a subfeed, not branch circuit. However don't assume this will work for everyone. Many center fed panels can take a max 70A circuit breaker. If you can fit a 125A on the buss, must of the time this is a slam dunk.
4. Definitely avoid moving the Main panel, there's always better solutions. However if your main panel is within 36" of your is gas riser vent, your choices are more limited.
 

dancudds

Member
Nov 1, 2019
96
26
San Francisco
On option 3
1. Depending on the size of the Powerwall and solar system this is true. Follow the advice of your design professional.
2. Absolutely
3. I think you mean a subfeed, not branch circuit. However don't assume this will work for everyone. Many center fed panels can take a max 70A circuit breaker. If you can fit a 125A on the buss, must of the time this is a slam dunk.
4. Definitely avoid moving the Main panel, there's always better solutions. However if your main panel is within 36" of your is gas riser vent, your choices are more limited.

Thanks to you both

For Options 3 - does this also require a subpanel for all loads backed-up? I'm struggling to see how to disconnect the service in the event of grid failure
Option 4 - If I can repurpose my combo panel as a main and have them splice the service line to add a service panel maybe I'm ok dollar-wise?
 

Vines

Active Member
Jul 20, 2018
2,078
2,495
Silicon Valley, CA
3 Requires a subpanel. You basically drop the largest breaker you can safely land on the buss, then relocate your loads to a subpanel on the other end of that breaker.
Depending on the breaker size and your system size, you may be able to relocate all your loads. Some times you'd have to use the 100% rule, others, this may be complaint with the 120% rule (705.12.d.2.3)
4. No idea what you are looking to do here. Combo panels can sometimes be converted to main breaker only, but is still a combo panel.

Typically a basic design you come out of the combo panel after the main breakler and meter with the biggest wire you can safely land, then to gateway and to AC disconnect if required and generation and loads subpanels.
 

wwhitney

Member
Nov 2, 2017
981
1,342
Berkeley, CA
In theory you could abandon the meter socket in a combo panel, intercept the service entrance conductors, and add a meter socket and gateway before the combo panel. In practice moving the service entrance conductors is too expensive.

In theory you could intercept the wiring internal to a combo panel, between the meter and the distribution section, and connect a gateway there. In practice, that would only be allowed with a sign-off from the combo panel manufacturer and/or an on-site inspection by a listing agency, both of which are too expensive.

Cheers, Wayne
 

dancudds

Member
Nov 1, 2019
96
26
San Francisco
3 Requires a subpanel. You basically drop the largest breaker you can safely land on the buss, then relocate your loads to a subpanel on the other end of that breaker.
Depending on the breaker size and your system size, you may be able to relocate all your loads. Some times you'd have to use the 100% rule, others, this may be complaint with the 120% rule (705.12.d.2.3)
4. No idea what you are looking to do here. Combo panels can sometimes be converted to main breaker only, but is still a combo panel.

Typically a basic design you come out of the combo panel after the main breakler and meter with the biggest wire you can safely land, then to gateway and to AC disconnect if required and generation and loads subpanels.
Understood - what a waste of that massive main combo to just have a 125a breaker on it :( I don't really have any other large loads such as AC etc.
I'm also worried about the wire routing for a subpanel and space I have near the main panel.

I'm just preparing for the worst that my main panel upgrade is a lost cost here.
 
Jun 22, 2017
527
338
Bay Area, California
@Vines For option 3. I did mean a branch circuit on the service panel bus. (Recall you and @wwhitney advised me on this for my main lug only service panel, and then Tesla pulled thru the rest of the way.) Yes, subfeed lugs is a preferred over option 3.

@dancudds Having a 125A breaker isn't a complete waste. Often times, main breakers are downsized anyway to create more room for backfeed for the 120% rule. The backup panel is likely to have a 200A bus which allows more Powerwalls and solar panels for the future, and may eliminate generation subpanel. Less ADDED panels = less work. The bonus is that you still have 200A available for EVs, backyard, or induction stove upgrade tho' not backed up. Those whose main breakers are downsized are capped could be considered "a waste."
 

wwhitney

Member
Nov 2, 2017
981
1,342
Berkeley, CA
Not following this thread closely, but FWIW while most residential panels limit breakers to 125A per bus connection point, some manufacturers make larger than 125A breakers that use two bus connection points per leg. So they take up 4 spaces instead of 2. In which case, you could have a 200A breaker in a 200A main breaker panel.

Cheers, Wayne
 

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