Electrical Panel & Solar - Center Fed and 100A?

[jsquared22]

It seems I have 2 challenges with my home’s service panel with regards to installing solar.

1. Center fed panel
2. Service panel rating? I’m Unable determine exactly my service panel’s maximum rating. The main breaker is 100A, but the sticker inside the panel door is missing. I checked 8 neighbors’ panels and they’re missing labels as well. Is there any way to determine if my service panel is capable of 125A but degraded to a 100A main breaker?

A solar contractor recommended getting a renewable meter adapter (RMA). The device must be purchased and installed by the utility company SDGE for a price of $1,400. Picture contained in the URL below.

https://www.sdge.com/sites/default/files/documents/744395783/RMA%20Flyer%20FINAL%201-28-15.pdf?nid=13641

At this point, it seems my 2 choices are either a panel upgrade, or the renewable meter adapter. Got any other ideas or considerations?

Recommendations or suggestions are appreciated.

Thanks,
Jsquared22

[solarix]

The panel looks a little large for just 100A, but if your neighbors all have the same thing then no doubt is. Other than an upgrade or the meter adapter, you could derate the main breaker by putting in a 75A Main (if available in your style). Will probably have to do a load analysis for the building dept which might not fly and you'll have to do a changeout with the utility too. Pretty hard to run a house on a 100A panel these days anyway. We do a lot of service upgrades to 200A when adding solar here. Even a 200A panel is maxed out by a 7.7kW inverter. At least you can include the panel upgrade in your solar tax credits.

[foo1bar]

Pretty hard to run a house on 100A these days anyway.

Not really...
Looking at my house:

AC is <30A (mine measured today at 3.1kW, but let's worst-case it with a bigger unit and startup amps being higher)
Pool pump is 7A
All the lights, refrigerator, freezer, computers, TVs, etc - all of those together are ~10A (Let's even give worse case that they're not balanced across the two phases, so they're 20A)

Altogether, that's still less than 60A.

So running a house on 100A - not a problem.
(I know lots of people who had 60A service to their home for many many years)

*But*
Most likely to meet code compliance, you won't be able to go much smaller than 100A. You'd have to actually do the calculations.
(ex. http://ecmweb.com/code-basics/dwelli...r-calculations - older article based on older code version - but gives you an idea of what a PITA it will be to calculate whether you can do 90A or 75A.

As for the OP:
A "line side tap" is another option beside the obvious one of replacing the panel.
I don't know much about them and couldn't tell from the picture if your main breaker was fed by wires or a metal bus. (they're doable with wires, not with a all-in-one meter/breaker panel where it uses a metal bus to feed into the main shutoff.)

I'd probably go with replacing the panel if it were me.
But if the "renewable meter adapter" is a lot cheaper and there's not any other factors to make you want to upgrade the panel, going that path could make a lot of sense.

[sensij]

Sdg&e requires 100 A min, so dropping the main to 75A is not an option.

[Alisobob]

At least you can included the panel upgrade in your solar tax credits.

...Bingo.

[jsquared22]

I'd probably go with replacing the panel if it were me.
But if the "renewable meter adapter" is a lot cheaper and there's not any other factors to make you want to upgrade the panel, going that path could make a lot of sense.

Like everyone else, I'd like to keep cost minimized, however, I'm thinking that a panel upgrade would be a better long term fit. Based on other posts I've read, the panel upgrade might possibly be achieved for a few hundred dollars more than the SDGE Renewable Energy Adapter.

[jsquared22]

At least you can included the panel upgrade in your solar tax credits.

Thanks for the tip on the tax credits solarix.

[jsquared22]

Does anyone have brand recommendations for the new panel brand, configuration, or lessons learned with the new install? Also, any idea if it will require stucco work?

[solarix]

Some manufacturers have a panel style called "farm panel" that is actually designed and listed for doing line-side taps making large solar installs easy - they also have versions where the busbar is oversized (like a 225A rating for a 200A panel - a good thing for solar). Not saying you need this - just a factoid. Other than that, get a brand that is common in your area (probably Cutler/Hammer, SQ-D or Siemens) and has breakers including the smaller duplex (half-size) available. And get a style that will require the least amount of wire splicing to your existing circuits and has lots of spaces - room for expansion.

[jimqpublic]

How about: Siemens Model # MC0816S1200SCT
200-Amp 8-Space 16-Circuit Surface Mount Meter Combo with 100-Amp Solar PV Input

$469 at Home Depot

[solarix]

or: Siemens 200-Amp 40-Space 40-Circuit Surface Mount Meter Combo with 100-Amp Solar PV Input

Model # MC4040S1200SC $424.88

[foo1bar]

How about: Siemens Model # MC0816S1200SCT
200-Amp 8-Space 16-Circuit Surface Mount Meter Combo with 100-Amp Solar PV Input

$469 at Home Depot

That's a surface mount.
I think he'll want a "semi-flush" mount to replace existing semi-flush mount installation.

Probably something like

http://www.homedepot.com/p/Square-D-Homeline-200-Amp-20-Space-40-Circuit-Semi-Flush-Mount-Main-Breaker-CSED-SC2040M200F/204251469

Will require some stucco work - but if it's same width that won't be too bad IMO.


The bigger question is whether you're going to upgrade the service.
If you are, that's another whole thing that you would have to deal with.
If not, the main breaker on the SC2040M200F would need to be replaced with 100A breaker.

[foo1bar]

The bigger question is whether you're going to upgrade the service.

SC1624M125F might work better if not upgrading the service...
Or the M100F version maybe if that's still a 125A bus. (probably is - but would need to check)

You'll have some measuring to do and figuring out whether you want to spend a whole bunch more money on upgrading the service. (not too expensive if overhead, but can be a much much bigger project if underground service)

[Alisobob]

Does anyone have brand recommendations for the new panel brand, configuration, or lessons learned with the new install? Also, any idea if it will require stucco work?

http://www.eaton.com/Eaton/ProductsServices/Electrical/ProductsandServices/Residential/GroupMeteringandMeterBreakers/SolarPowerCenters/index.htm

I got a Eaton with my install.... its specifically made, and labeled, for solar installs.

solar f2.jpg

[jsquared22]

SC1624M125F might work better if not upgrading the service...
Or the M100F version maybe if that's still a 125A bus. (probably is - but would need to check)

You'll have some measuring to do and figuring out whether you want to spend a whole bunch more money on upgrading the service. (not too expensive if overhead, but can be a much much bigger project if underground service)

Since my current 20 year old panel lacks information for me to confirm if it's truly a 125A panel degraded to 100A, and the SDGE Renewable Meter Adapter is not yet available (and will cost $1,400), then I'm going to investigate a new panel install without upgrading the service. I'll update this thread with the results.