Main service panel connection to gateway amperage

[hiltxan]

I have a 200A main service panel. Tesla came back with this design. It appears it goes from main panel--125A--Gateway--125A--distribution panel for the house loads. They offered whole home backup and relocating all the circuits onto the distribution panel. My main appliances are induction stove (40A), electric oven (50A), EV charger (60A), pool pump (30A) and A/C (40A) with a 2600 square foot house.

1. Does it appear that I won't be able to draw more than 125A for the entire home? It seems that my home got downgraded to 125A from my current 200A main service panel. I've brought this up to them multiple times and the last response I got was that the design and engineer team has determined 125A is enough and I can change it to 200A later with my own contractors. Has anyone gotten a 200A connection between the main service panel and gateway and distribution panel from Tesla?
2. Tesla has claimed that the distribution panel can support up to 200A (drawing amperage from main service panel and the powerwalls) but I can't see how this is possible if the circuit breaker is 125A?
3. Does Tesla submit PTO in advance of NEM 3.0? They say they don't but I thought you can?
4. For circuits on the main service panel, can those utilize the powerwall during peak hours?

 

[TerranApart]

It might be due to the 200A bus of the Tesla Gateway.
200A bus * 120% = 240Amps.

You are feeding in 125A from the main panel plus up to 100A from the two powerwall+ units (2x 50A) for a total of 225A, which is within the 240A limit of the GW2 bus.

- OR -
125A might be the largest branch breaker available to Tesla for your specific main panel, or perhaps the main panel has a 125A maximum bus stab rating.

All just guesses.
Someone more qualified (like @wwhitney ) could give you more/better info.

 

[Vines]

I have a 200A main service panel. Tesla came back with this design. It appears it goes from main panel--125A--Gateway--125A--distribution panel for the house loads. They offered whole home backup and relocating all the circuits onto the distribution panel. My main appliances are induction stove (40A), electric oven (50A), EV charger (60A), pool pump (30A) and A/C (40A) with a 2600 square foot house.

1. Does it appear that I won't be able to draw more than 125A for the entire home? It seems that my home got downgraded to 125A from my current 200A main service panel. I've brought this up to them multiple times and the last response I got was that the design and engineer team has determined 125A is enough and I can change it to 200A later with my own contractors. Has anyone gotten a 200A connection between the main service panel and gateway and distribution panel from Tesla?
2. Tesla has claimed that the distribution panel can support up to 200A (drawing amperage from main service panel and the powerwalls) but I can't see how this is possible if the circuit breaker is 125A?
3. Does Tesla submit PTO in advance of NEM 3.0? They say they don't but I thought you can?
4. For circuits on the main service panel, can those utilize the powerwall during peak hours?

View attachment 882197

Likely your physical service panel will accept only a maximum of a 125A breaker on the bus.

To get the full 200A you will need a new service panel. You are limited to 125A in this design from the grid.

 

[hiltxan]

Is there any 150A or 175A option?

I'm guessing that the line between the gateway and backup panel can only be 125A (connection 4), not 200A, if the line (connection 5) between gateway and main panel is only 125A?

 

[Vines]

Is there any 150A or 175A option?

I'm guessing that the line between the gateway and backup panel can only be 125A (connection 4), not 200A, if the line (connection 5) between gateway and main panel is only 125A?

Wire 4 and wire 5 are independent of each other, and so one could be sized larger than the other. I cannot say whether Tesla will do this.

There probably isn't a 150A or 175A breaker that will fit there correctly. once you get larger than 125A breakers in a siemens/Murray panel you need to have a 4 pole connection, and have 2 parallel busbars where you can stab a larger frame breaker across both buses at once. Since you have a center-fed panel this isn't possible, and there isn't likely physical room for the approx 4" bend radius that you would need between a 200A breaker terminal and the edge of the enclosure.

 

[YRide]

In a similar situation...

Tesla indicate they will only backup partial, and will NOT include either of my EVSE's. I don't need both...but was really hoping for at least one (since we only have EV now...if there's a power outtage want to have the option).

It seems like this is an issue because my main panel is 100A limited for max branch breaker. Is this typical for a 200A main panel? Or are there main panels out there that would let me go a full 200A (or even just 150A or 175A) on a branch breaker?

I guess is the other option that the total load calc for a whole home backup comes in <200A, in which case can't they just backup everything and then the re-location to a new 100A limited load center goes away? If so, is this just limited by the amount of Powerwalls? So in my case below...2xPW+ and 2xPW2 = 50 + 50 + 30 + 30 = 160A? And so if my load calc for the entire house (full backup) was <160A, then Tesla could just backup my Main Panel directly?

@holeydonut this is related to your comment on making PV+ESS easier...

@wwhitney also per my load calc comments on other thread. Trying to get every A out of there...

Y

 

[wwhitney]

It seems like this is an issue because my main panel is 100A limited for max branch breaker. Is this typical for a 200A main panel?

Not typical, but common. See Tesla surprises with a $4800 bill on existing $5300 install contract for info on this specific case.

Or are there main panels out there that would let me go a full 200A (or even just 150A or 175A) on a branch breaker?

Yes, there are. But then you have to upgrade your service panel with the resulting costs and potential PG&E hassle (particularly if you have a gas riser within 36" of the panel, or some other no longer allowed location detail).

I guess is the other option that the total load calc for a whole home backup comes in <200A, in which case can't they just backup everything and then the re-location to a new 100A limited load center goes away?

No. The problem is that without replacing your service panel, there's no approved way to make a connection larger than 100A to the existing bus. So the Backup Gateway could only be supplied at 100A, and if you want everything backed up, you'd be limited to 100A from the grid.

Cheers, Wayne

 

[YRide]

Yes, there are. But then you have to upgrade your service panel with the resulting costs and potential PG&E hassle (particularly if you have a gas riser within 36" of the panel, or some other no longer allowed location detail).

Would one of these CSED's work? All-in-Ones | Schneider Electric USA

MSRP on Schneider are like $2k, but it seems like Home Depot, Amazon, etc are like $300.

Right edge of my panel is technical 36" from the vent on gas riser...house is pretty new construction so I guess that forced that. However, if I went slightly wider panel and it went to the right, I would encroach. That said, I had PG&E install one of those slam-shut devices, which my understanding allows you to drop to 12" from electrical or window, etc. So i think I have space to be closer.

No. The problem is that without replacing your service panel, there's no approved way to make a connection larger than 100A to the existing bus. So the Backup Gateway could only be supplied at 100A, and if you want everything backed up, you'd be limited to 100A from the grid.

Per above link it looks like a number of 200A (and also 225A) CSED's that have 200A max branch breakers.

In that case can the main panel be backed up? Or regardless of having 200A max branch breaker, there will still be a main CSED, then the backup gateway, then behind it another 225A load center with all my home loads (now all backed up) as well as another 225A load center for the four PW's? Asked another way...is there any way to have only 3 main panel / load centers? Or will I have to have 4?

Still dont understand back-fed...and is it required (or is it allowed) in my case...

 

[wwhitney]

Or regardless of having 200A max branch breaker, there will still be a main CSED, then the backup gateway, then behind it another 225A load center with all my home loads (now all backed up) as well as another 225A load center for the four PW's?

Mostly yes.

The internal panelboard may be able to handle the role of the PW panel, using quad 30/30 breakers (each of which supports 2 double pole 30A circuits and takes up 2 of the 6 spaces). I'm not up on the details of whether there's a snag in that idea--a while back there was a discussion here on whether the manufacturer's holddown device for quads was available and acceptable. I guess even if you can't use the quads, you could use (3) double pole 30A breakers in the internal PW panelboard, and 1 in the load panel under the 120% rule.

Another option is to use a standalone meter base (rare in CA), with the service conductors landing in the Backup Gateway 2, which can accept a main breaker on the line side and become the service disconnect. The Backup Gateway 2 would then need to be outside to serve the as 2020 NEC required Emergency Disconnect; if you want it inside, you might as well use a meter/main breaker/no distribution type CSED outside.

Cheers, Wayne

 

[YRide]

Mostly yes.

The internal panelboard may be able to handle the role of the PW panel, using quad 30/30 breakers (each of which supports 2 double pole 30A circuits and takes up 2 of the 6 spaces). I'm not up on the details of whether there's a snag in that idea--a while back there was a discussion here on whether the manufacturer's holddown device for quads was available and acceptable. I guess even if you can't use the quads, you could use (3) double pole 30A breakers in the internal PW panelboard, and 1 in the load panel under the 120% rule.

Another option is to use a standalone meter base (rare in CA), with the service conductors landing in the Backup Gateway 2, which can accept a main breaker on the line side and become the service disconnect. The Backup Gateway 2 would then need to be outside to serve the as 2020 NEC required Emergency Disconnect; if you want it inside, you might as well use a meter/main breaker/no distribution type CSED outside.

Cheers, Wayne

Why rate in CA? Difficult to get approved? Or just not practical?

It would seem if I want while home (200A) backup I’m going to need to replace my CSED panel anyway, right? So if I’m doing that, isn’t the simplest option to just install a 200A CSED with a 225A bus bar, and 200A max branch rating?

This panel would then have my 200A main disconnect. It would also have all my home loads (as it does today), fully backed up now.

Then would the CSED would be connected to the GW2 through a 200A breaker?

Then on the other side of the GW2 would a 175A AC disconnect switch.

Then on the other side of the disconnect, a 225A load center where all the PW’s are connected to?

In this setup I would only two panels (a 200A main/CSED and a 225A load center)?

Basically removing the need for Load Center “U” in above diagram + taking my backed up loads from 100A to 200A?

What would be the benefit of going standalone meter? Doesn’t it add just a little more complexity? Still need two panels, and now a standalone meter?

 

[wwhitney]

Why rare in CA? Difficult to get approved? Or just not practical?

Rare = local practice, I don't know if it's just convention or if the POCO won't like it for some reason.

It would seem if I want while home (200A) backup I’m going to need to replace my CSED panel anyway, right? So if I’m doing that, isn’t the simplest option to just install a 200A CSED with a 225A bus bar, and 200A max branch rating?

This panel would then have my 200A main disconnect. It would also have all my home loads (as it does today), fully backed up now.

Only if you are able to use the Backup Meter Switch, again which I don't know the CA approval status of. If you are using the Backup Gateway 2, then you'd need to have all your backed up loads on the opposite side of the GW2 from the grid. So no backed up loads in the CSED.

Simplest is to have a CSED with no bus, just a meter and a main breaker. The load side of the main breaker is connected to your Backup Gateway 2, and then you have two panels downstream of it, one for loads and one for PWs. It may be possible to put the one for PWs inside the GW2, as discussed.

Cheers, Wayne

 

[YRide]

Rare = local practice, I don't know if it's just convention or if the POCO won't like it for some reason.


Only if you are able to use the Backup Meter Switch, again which I don't know the CA approval status of. If you are using the Backup Gateway 2, then you'd need to have all your backed up loads on the opposite side of the GW2 from the grid. So no backed up loads in the CSED.

Simplest is to have a CSED with no bus, just a meter and a main breaker. The load side of the main breaker is connected to your Backup Gateway 2, and then you have two panels downstream of it, one for loads and one for PWs. It may be possible to put the one for PWs inside the GW2, as discussed.

Cheers, Wayne

Ok…so the two options are:

Simplest (but more rare in CA):

Grid - Meter / 200A main breaker only - GW2 - 225A LC for whole home backup + 225A LC for PV/ESS (two load centers in parallel).

More std, a bit wasteful

Grid - Meter / 200A main breaker / empty panel (200A CSED) - GW2 - 225A LC for whole home backup + 225A LC for PV/ESS (two load centers in parallel).

I am putting the PW’s outside now, and thus GW2 would be outside. Is the requirement just outside? Or does it have to be streetside in front of gate/fence as well?

Still don’t understand what the purpose would be to put one of the four PW on the GW2? I still have to have 3 in a load center. Does it just make more sense to keep all 4 together?

Thx again for your seemingly unlimited knowledge on this stuff!