Why "critical load panel only" when grid is down?

[jflorey2]

Thoughts?

Attached is the more conventional/safer way to do it. inverter.bmp

[Sunking]

Get a genny and ATS. Everything works in your home while you kick back, relax, and watch your neighbors suffer. Lot less expensive than your way with extremely limited power.

[kingofbanff]

Attached is the more conventional/safer way to do it. [ATTACH=CONFIG]n308361[/ATTACH]

In your diagram are the only backed up loads the "essentials panel"? It looks as though once the grid goes down the main panel is dis-connected from the inverter.
One of my requirements is to not have to rewire and thus have everything backed up. Thanks

[Sunking]

In your diagram are the only backed up loads the "essentials panel"? It looks as though once the grid goes down the main panel is dis-connected from the inverter.
One of my requirements is to not have to rewire and thus have everything backed up. Thanks

City of Denver is not going to sign off on your plan. By code you must rewire your home for an emergency panel. With a Genny, no rewiring, no batteries to replace every few years, no expensive Hybrid inverter, and no limitations on power.

[Mike90250]

......

The designer proposes a 200 amp contact switch in between the meter and the main panel. When the grid goes down the switch prevents the back feeding of the grid.....

DANGER DANGER

A home-brew transfer switch is NOT acceptable. You can ONLY use a UL certified transfer switch, That switch is usually internal to the Solar GT inverter.
if not, that DIY switch is not an accepted device, There are " generator Lock-Out" gates that fit over 2 pairs of breakers in a panel, to switch a house from grid to generator power, but these are designed to only allow one or the other, with no chance of both happening.

Your "designer" (or your interpretation of his design) is flawed

[gmanInPA]

You might seek a second opinion on the wiring up of a critical loads panel if you're bent on going the solar route. An electrician might have better ideas about such then a designer.

[ButchDeal]

In your diagram are the only backed up loads the "essentials panel"? It looks as though once the grid goes down the main panel is dis-connected from the inverter.
One of my requirements is to not have to rewire and thus have everything backed up. Thanks

Get another designer. Besides all the problems mentioned so far it will not work anyway. AC1 will go down if disconnected from the grid. You are finding it hard to do what you are trying to do because it can't be done.

[gmanInPA]

You're killing yourself to get "everything backed up", but this isn't feasible unless budget and effort are both inexhaustible. With a hybrid inverter, batteries, generator, and pv, you can still get your whole house backed up but in a reasonable fashion. Several of us here are living with such systems.

Think about this... Why have your non-critical loads backed up with batteries? If you did so and decided to run your oven in a power outage - you'll beat your batteries senseless and one or more large inverters will be needed. That's just for the oven. You'll get far better options by finding alternative ways of accomplishing your non-critical functions without power than trying to run them off batteries. Example... Instead of getting 6 tons of batteries that cost $20k so you can run the oven in a power outage - get a wood or propane cook stove for $2k.

[kingofbanff]

I really really appreciate the comments and I'm sorry I have been muddy on my thoughts. I don't want to have everything backed up at all times. When my 13 kW system is bathed in sunshine and the grid is down I would like to have the option to use that power to run any of my normal needs. If my battery bank is full and it's daylight so I'm not running any lights it would be great to run my attic fan or my dishwasher or my laundry or my power saw.
What I seem to be reading here is I will only be allowed by my electrical inspector to have a critical load panel that can be supported just by my batteries regardless if I have 10kw coming out of my modules. So due to not wanting a gazillion batteries I'll just have to let a lot of electricity go to waste on a sunny day if the grid is down.
Is that right?

[jflorey2]

In your diagram are the only backed up loads the "essentials panel"? It looks as though once the grid goes down the main panel is dis-connected from the inverter.
One of my requirements is to not have to rewire and thus have everything backed up.

Why the heck not? You can get an electrician to put in a second panel (and relocate all your critical loads) for $500-$1000, less than you will spend on all that other stuff you are listing. You are already saying things like "So then when I realize the grid is down it is up to me to manually trip all the breakers that I don't want drawing from the batteries" - that means there are loads you don't want drawing power. Those stay on the main panel. Your critical loads stay on the essentials panel. And then the system is foolproof - and more importantly, will actually be legal and safe.

And the bonus is that once you do this you don't even need a transfer switch. It's built in to the inverter.

[gmanInPA]

Some hybrid inverters support the loads all the time, and then direct the surplus toward the "grid". If the inverter is in a branch circuit from your main panel, then the "grid" includes the main panel and the surplus power is available to the demands on the main panel. After those demand are met (if) the power is fed to the utility. The only time the inverter cannot direct surplus power back to the main panel in this scenario is when there is a loss of grid power. This is a purposeful feature of hybrid inverters to prevent harming line workers.

You can self-consume all your pv power - except during a grid outage at which point you can only consume power for your critical loads.

[inetdog]

Some hybrid inverters support the loads all the time, and then direct the surplus toward the "grid". If the inverter is in a branch circuit from your main panel, then the "grid" includes the main panel and the surplus power is available to the demands on the main panel. After those demand are met (if) the power is fed to the utility. The only time the inverter cannot direct surplus power back to the main panel in this scenario is when there is a loss of grid power. This is a purposeful feature of hybrid inverters to prevent harming line workers.

You can self-consume all your pv power - except during a grid outage at which point you can only consume power for your critical loads.

And the way that they make it safe is with an internal transfer switch that disconnects the inverter output, and the critical load panel that remains connected to it, from the AC in (AC1 in) terminals when the grid goes away.
This is an automatic function, unlike the manual switching the OP is proposing to use.

[Djcoak]

Guest How often does your grid power go out? Is it worth worrying about? Geez, the last time that happened here I think I fell off my dinosaur. If and when it does, good time to go for a run or take the dog for a walk till it comes back up.

seems fairly naive. Although his goals seem lofty, to just wait it out is what most the population will do, till it doesn't come back for a day, a week, 2 weeks...... Been in two situations with no power, once for two weeks during an ice storm and a week after sandy. Better prepared than not

[Djcoak]

I really really appreciate the comments and I'm sorry I have been muddy on my thoughts. I don't want to have everything backed up at all times. When my 13 kW system is bathed in sunshine and the grid is down I would like to have the option to use that power to run any of my normal needs. If my battery bank is full and it's daylight so I'm not running any lights it would be great to run my attic fan or my dishwasher or my laundry or my power saw.
What I seem to be reading here is I will only be allowed by my electrical inspector to have a critical load panel that can be supported just by my batteries regardless if I have 10kw coming out of my modules. So due to not wanting a gazillion batteries I'll just have to let a lot of electricity go to waste on a sunny day if the grid is down.
Is that right?

i don't understand why you feel these are needed items. Do you not understand the situation you will be in during a long term power outage? You'll live without AC, do the dishes by hand and get a grill for cooking. Honestly the other items are nice but you're ignoring the advice being given to you. The laundry I get but the others I don't. Attic fan, Really???? Stop being a selfish yuppy and understand that your not going to get all the extras in the system you want and are not needed in an EMERGENCY
Geez.

[DaveDE2]

seems fairly naive. Although his goals seem lofty, to just wait it out is what most the population will do, till it doesn't come back for a day, a week, 2 weeks...... Been in two situations with no power, once for two weeks during an ice storm and a week after sandy. Better prepared than not

Naive, I don't think so but if you'd have said it was none of my business, I'd have no argument with that.

I was only giving him a little guff because I've lived about 30 miles from his location most of the past 50 years and can't remember ever having the power out for more than a few hours once every 5 or 10 years or so. We have different pocos but live in almost identical climatic conditions except the wind here in Boulder county is probably a lot worse. Maybe kingofbanff's poco situation is bad though (I'd be surprised), or maybe he's just got cash burning a hole in his pocket. Doing what he's doing just seems extreme to me. I know of no one else around here who's worried about it. I was only suggesting that he reconsider how important it really is before charging down the path...