No load center/electrical panel upgrade needed?

[bossturbo]

My 8.16kW system design came back a few hours after submittal yesterday (Saturday) morning. My house has a 100 amp electrical panel, which was clearly shown in the photos submitted. In the design and purchase agreement there is no mention of upgrading the panel.

Are these designs automated and they'll adjust on Monday, or is no electrical panel upgrade needed?

A local company quoted $2000 for "in place"/switchout 200 amp panel upgrade as part of their $20,400 7.2kW Panasonic/Enphase quote.

 

[CrazyRabbit]

California likes to install combined service entrance and loads panels, which limits your choices.
Texas likes to install meter base with circuit panels inside. When my solar was installed they just triple tapped my meter base and wired straight to meter base.

 

[bossturbo]

Correct, my panel is a combined service entrance, meter, load center.

 

[SoCal Dave]

Unlikely, but is your panel rated for higher amperage than your main breaker? If not, the largest solar panel breaker they can use would be 20A which isn't sufficient for an 8kW install.

They could potentially derate your main breaker and install something smaller, but I'd be surprised with anyone going with a main breaker smaller than 100A.

Or, they could also do a line side tap, but personally I don't care for that.

 

[bossturbo]

It's rated for 100 amps max. I just googled line side tap. Seems like a clever way of getting around a panel upgrade. Why is a line side tap not a good thing? Janky?

 

[GHall]

It's rated for 100 amps max. I just googled line side tap. Seems like a clever way of getting around a panel upgrade. Why is a line side tap not a good thing? Janky?

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I have that same panel and I have the on site inspection for my solar roof install tomorrow morning. I will let you know the results.

 

[SoCal Dave]

It's rated for 100 amps max. I just googled line side tap. Seems like a clever way of getting around a panel upgrade. Why is a line side tap not a good thing? Janky?

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It is legal and there are lots of installs where it was done. It just feels like a bit of a hack in my opinion.

Personally, I would just upgrade the panel, but I can do it myself. Now if I had to pay $2,000 - $5,000 for a panel upgrade, a line side tap probably would be sounding better

They definitely aren't going to be able to derate your main breaker with the AC, cook-top and other loads you have there.

 

[SoCal Dave]

I have that same panel and I have the on site inspection for my solar roof install tomorrow morning. I will let you know the results.

Don't be surprised that the on site inspector doesn't tell you anything. Mine just took photos and then I got a call later from someone at Tesla with questions about what was observed.

 

[GHall]

Don't be surprised that the on site inspector doesn't tell you anything. Mine just took photos and then I got a call later from someone at Tesla with questions about what was observed.

Got it. Thanks!

 

[wwhitney]

Line side tap on a combined meter/main is generally not possible. The conductors from the meter to the main are factory installed, rather than field installed, so modifying them would require the manufacturer's approval.

Options I see:

a) Upgrade service entrance
b) Downgrade main breaker to 90 amps and use a 5.76 kW inverter (assuming those exist). That would give you a DC/AC ratio of 1.41, which is on the high side but still reasonable (i.e. the 24th (last) panel is probably still worth it and not worth deleting). An NEC load calc showing 90A as sufficient would be required.
c) Add a 100A subpanel and move all the branch circuits to it. Run a 100A feeder from the meter/main to the subpanel; the solar inverter is connected to this feeder at a splice box.

Unless (c) is alot less expensive than (a), I'd say it's not worth it, just go with (a).

Cheers, Wayne

 

[bossturbo]

It is legal and there are lots of installs where it was done. It just feels like a bit of a hack in my opinion.

Personally, I would just upgrade the panel, but I can do it myself. Now if I had to pay $2,000 - $5,000 for a panel upgrade, a line side tap probably would be sounding better

They definitely aren't going to be able to derate your main breaker with the AC, cook-top and other loads you have there.

Yeah, the panel is maxed out and beyond, in my opinion. Two 30 amp ovens, a 60amp for A/C. I haven't tried turning everything on at once, but I would imagine it would trip the main breaker. Nearly every circuit in there is 20 amp, only one or two 15 amp.

Thanks ghall and socal dave for the feedback. I'm a big DIY'er, and love learning new projects and considered doing the entire solar project myself. I'm comfortable around electricity, but decided that given the 2 story house and roof tile to deal with, and all these little "gotchas", I'll leave all these headaches for someone else.

 

[bossturbo]

Seems like a line side tap would be hard to do here, seems pretty cramped.

 

[SoCal Dave]

Seems like a line side tap would be hard to do here, seems pretty cramped.

You are probably looking at a panel upgrade.

A subpanel is a potential option as @wwhitney suggests. However, if you are allowed to keep your meter in the same location, a panel upgrade won't be significantly more than a subpanel. But it would probably be good to go to a 200A anyways with all the electric applicances you have.

Is your meter near a side gate where the power company can read it easily? Usually a meter being on the backside of a house where they can't read it is the driver for them forcing it to be moved. Kinda silly with meters now being wireless, but they still enforce this. Moving a main panel is significantly more expensive and time consuming than an in place upgrade.

 

[bossturbo]

You are probably looking at a panel upgrade.

Agreed. I was just wondering why Tesla did not add it to the project cost. Is that something they would add after a prelim on-site check, via a change order?

It should be a "simple" in-place swap out. It's easily accessible on the side of the house with no gates in front of it. The only thing I'm not sure about is distance to gas lines and meter, it's about 5-6 feet away I would guess.

 

[wwhitney]

PG&E, at least, only requires 36" clearance from the gas riser coming out of the ground. Your utility may vary.

 

[SMAlset]

Agreed. I was just wondering why Tesla did not add it to the project cost. Is that something they would add after a prelim on-site check, via a change order?

It should be a "simple" in-place swap out. It's easily accessible on the side of the house with no gates in front of it. The only thing I'm not sure about is distance to gas lines and meter, it's about 5-6 feet away I would guess.

We had a MSP upgrade required. Brought up at permit time and after city checked what equipment the developer installed (200A but was not 225A bus which they wanted). Tesla came back and said they could do the work (would be a separate contract) but the person in our area that did this work was booked out for months. So we elected to have it done by our electrician who had done this project work before. We were then required to provide evidence to Tesla that the work was completed and finalized by the city before proceeding. BTW as it turned out our electrician charged more than Tesla but was available in two weeks.

We have a stucco house and our flush mount MSP was pretty full so the removal, rewiring and restucco’ing the area was like a 3-4 day job if I remember. Not a simple swap out by any means. This was our old and new MSP.

 

[SoCal Dave]

Agreed. I was just wondering why Tesla did not add it to the project cost. Is that something they would add after a prelim on-site check, via a change order?

Dunno, my install didn't have an cost changes. I would suggest getting a couple of electricians to give you a bid on the service upgrade. The prices I've seen for additional electrical work through Tesla seem to be on the higher side.

 

[SoCal Dave]

We have a stucco house and our flush mount MSP was pretty full so the removal, rewiring and restucco’ing the area was like a 3-4 day job if I remember. Not a simple swap out by any means. This was our old and new MSP.

3-4 day job for a service upgrade? Did you hire city road repair workers to do it for you?

An in place upgrade should be a day long job for the actual work. I would get inspections and dealing with the electric company possibly taking longer than that, but it is a really straight-forward process.

How long were you without power?

 

[SMAlset]

3-4 day job for a service upgrade? Did you hire city road repair workers to do it for you?

An in place upgrade should be a day long job for the actual work. I would get inspections and dealing with the electric company possibly taking longer than that, but it is a really straight-forward process.

How long were you without power?

LOL, no that was from start to stucco finish and final. The removal of stucco took some time, mapping out of the 9 loads plus subpanel and 200A center breaker, panel removal and then more removal of stucco as the new panel was larger, installing that and rewiring, needed to add more flashing(?), at some point there was an inspection by city, then stucco guy came out and did two or three coats, then another inspection by city for the finalized permit. It was not a quick process. Haha and not factoring in getting the permit from the city and the 2 month wait due to covid shutdown of what was considered non-essential electrical work! Couldn’t get in Tesla’s queue until we had that final.

He had worked out in advance the wiring to be disconnected and reconnected so we only had power out for a small amount of time. Didn’t keep track but husband said not long at all.

 

[bossturbo]

@GHall any update?