Starting a new house from scratch with FCSP. Got advice on how to design panels/subpanels?

[Whitewater64]

I am designing a house to build in the mountains near me and have the opportunity to design the electrical from the ground up (pun acknowledged if not intended). I am in a rental, so installing the FCSP here made no sense and we have opted to hold and install it in the vacation house for several reasons: 1. It's OUR house, 2. It's easier because there is no re-wiring to do and 3. We are much more likely to have power outages up there (rural, mountain, icy, etc) than here on the desert floor.

So... Because I know several of you are real electrical engineers AND enthusiasts, why not post here for advice? I'd really appreciate your input. We are in final design phase with the house and just about ready to submit plans for permit. I hope to do it right the first time.

My thought was to do a 120A sub-panel fed off of the main 200A panel with a 120A breaker. In that sub, I could put the 100A for the FCSP and a few select 15-20A circuits to run necessities during power outages (fridge, MW, one other kitchen circuit and a circuit or two of lighting).

Is this the best way to plan this? Do I need an automated interrupter to pass CA electrical code or will manually flipping the 120A breaker be sufficient separation during power outages to quell the fears of the plan checkers at the county and power company?

Again, I really appreciate the input of the experts here.

How lucky am I? A 2023 F150 Lightning, a mountain getaway AND the opportunity to get the wiring done right BEFORE we install the FCSP???

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[Maquis]

If your intending to power that subpanel from the truck during an outage, you have to install a transfer switch in the line feeding that panel.

A standard panel size will be 125A, not 120.

I would install a separate, smaller subpanel for the backup loads and run the FCSP from the main. That will allow a much smaller (less expensive) transfer switch. A 60A sub will be fine without the FCSP in it.

Since you’re starting from scratch, have the main panel (both panels) near the garage.

….manually flipping the 120A breaker be sufficient separation during power outages to quell the fears of the plan checkers at the county and power company?

Don’t even go there. It’s unsafe and will get this thread locked!

 

[Tony Burgh]

I assume you’re going to be in the high desert. Solar makes perfect sense there. Hire, or have your architect hire, a qualified electrical deign firm to pull all systems together so that they perform as expected while meeting all codes and safety requirements.

 

[Whitewater64]

If your intending to power that subpanel from the truck during an outage, you have to install a transfer switch in the line feeding that panel.

A standard panel size will be 125A, not 120.

I would install a separate, smaller subpanel for the backup loads and run the FCSP from the main. That will allow a much smaller (less expensive) transfer switch. A 60A sub will be fine without the FCSP in it.

Since you’re starting from scratch, have the main panel (both panels) near the garage.


Don’t even go there. It’s unsafe and will get this thread locked!

That's why I asked. I knew there were people here with the knowledge.

 

[chl]

I am designing a house to build in the mountains near me and have the opportunity to design the electrical from the ground up (pun acknowledged if not intended). I am in a rental, so installing the FCSP here made no sense and we have opted to hold and install it in the vacation house for several reasons: 1. It's OUR house, 2. It's easier because there is no re-wiring to do and 3. We are much more likely to have power outages up there (rural, mountain, icy, etc) than here on the desert floor.

So... Because I know several of you are real electrical engineers AND enthusiasts, why not post here for advice? I'd really appreciate your input. We are in final design phase with the house and just about ready to submit plans for permit. I hope to do it right the first time.

My thought was to do a 120A sub-panel fed off of the main 200A panel with a 120A breaker. In that sub, I could put the 100A for the FCSP and a few select 15-20A circuits to run necessities during power outages (fridge, MW, one other kitchen circuit and a circuit or two of lighting).

Is this the best way to plan this? Do I need an automated interrupter to pass CA electrical code or will manually flipping the 120A breaker be sufficient separation during power outages to quell the fears of the plan checkers at the county and power company?

Again, I really appreciate the input of the experts here.

How lucky am I? A 2023 F150 Lightning, a mountain getaway AND the opportunity to get the wiring done right BEFORE we install the FCSP???

Lucky you!

I'd suggest underground service to your home from the utility.
Since you are in CA and in the mountains, I would also suggest you look into fire proof construction.
Solar integration might be an option if you have good southern exposure.

Using the lightning for back-up power, ditto to comments about a transfer switch being a must for safety.
There are really at least two ways to go with the back-up power:
1) use the Ford/Sunrun system or equivalent, or
2) hook up the 240v outlet in the Lightning bed to a manual transfer switch.

Method 1 will cost more, but if it works well, may be able to power more or all of your home's electrics. I have seen posts about problems/annoyances with the Ford/Sunrun system, but others have had it work well.

Method 2 requires a transfer switch that will switch the neutrals - it seems most modern transfer switches now do this, but double check - because the neutral can only be bonded (grounded) at one place, the source, in this case the Lightning. Otherwise the GFCI in the Lightning will trip.

I presume you are having a knowledgeable and experienced electrician do the work.
Even so it pays to double check the work and make sure that all the required inspections are done.

I had the experience of an electrician who switched the hot and neutral wires at the sub-panel in a shed he wired resulting in 240v being present at the 120v wall outlets which fried a drill before I detected it. Could have been a disaster, fire, injury, etc. I was lucky.

On a mountain, I would also suggest extra grounding at the service since higher elevations are more subject to lightning and other electrical discharges from the atmosphere. This means a few extra ground rods, and maybe even a service GFCI device.

Direct hits from lightning might be a risk on a mountain, so special lightning prevention/mitigation measures should be implemented:

East Coast Lightning Equipment is one of the largest suppliers of protection products in the country - see https://www.oldhouseonline.com/repairs-and-how-to/how-to-prevent-lightning-damage/

Last piece of advice is get multiple estimates for the work and check references, the BBA, your state consumer protection agency, etc. Make sure the installers get all the necessary permits - that was my one of my mistakes with the shed that was mis-wired - 20 years later an neighbor instigated an inspection of my shed and I had to get a permit and an inspection myself because there was none on record. Live and learn.

 

[Whitewater64]

Lucky you!

I'd suggest underground service to your home from the utility.
Since you are in CA and in the mountains, I would also suggest you look into fire proof construction.
Solar integration might be an option if you have good southern exposure.

Using the lightning for back-up power, ditto to comments about a transfer switch being a must for safety.
There are really at least two ways to go with the back-up power:
1) use the Ford/Sunrun system or equivalent, or
2) hook up the 240v outlet in the Lightning bed to a manual transfer switch.

Method 1 will cost more, but if it works well, may be able to power more or all of your home's electrics. I have seen posts about problems/annoyances with the Ford/Sunrun system, but others have had it work well.

Method 2 requires a transfer switch that will switch the neutrals - it seems most modern transfer switches now do this, but double check - because the neutral can only be bonded (grounded) at one place, the source, in this case the Lightning. Otherwise the GFCI in the Lightning will trip.

I presume you are having a knowledgeable and experienced electrician do the work.
Even so it pays to double check the work and make sure that all the required inspections are done.

I had the experience of an electrician who switched the hot and neutral wires at the sub-panel in a shed he wired resulting in 240v being present at the 120v wall outlets which fried a drill before I detected it. Could have been a disaster, fire, injury, etc. I was lucky.

On a mountain, I would also suggest extra grounding at the service since higher elevations are more subject to lightning and other electrical discharges from the atmosphere. This means a few extra ground rods, and maybe even a service GFCI device.

Direct hits from lightning might be a risk on a mountain, so special lightning prevention/mitigation measures should be implemented:

East Coast Lightning Equipment is one of the largest suppliers of protection products in the country - see https://www.oldhouseonline.com/repairs-and-how-to/how-to-prevent-lightning-damage/

Last piece of advice is get multiple estimates for the work and check references, the BBA, your state consumer protection agency, etc. Make sure the installers get all the necessary permits - that was my one of my mistakes with the shed that was mis-wired - 20 years later an neighbor instigated an inspection of my shed and I had to get a permit and an inspection myself because there was none on record. Live and learn.

Thanks. There is a LOT of info here. I really appreciate you taking the time...

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