Separating circuits from the grid

smoothJoey

Ooga Booga!
DON'T TRY THIS AT HOME!

Scenario
Half my living space is on one 15amp fuse

The plan is to put that living space on UPS
this space shall be called "the ups protected space"

The UPS is either an inverter/charger/with automatic transfer switch + battery
or
an inverter + discrete AC charger + battery

The UPS gets power from a circuit outside of the UPS protected space
The fuse for the UPS protected space is removed
The UPS protected space is energised via
a suicide cord from the inverter to an outlet in the UPS protected space

The neutral ground bond is somewhere beyond my control upstream of my fuse box

With the inverter/charger in passthrough(transfer switch) mode
will I have problems with multiple neutral paths?
With the inverter/charger running in battery mode
will I have problems with multiple neutral paths?
With the inverter and discrete charger
will I have complete galvanic isolation for the UPS protected space?

I have an idea for a test...
If I have a gfci outlet in the UPS protected space
and I can run a load without tripping the outlet breaker
then things are good right?
 
Last edited:

SolarRat

Photon Sorcerer
Scenario
Half my living space is on one 15amp fuse

The plan is to put that living space on UPS
this space shall be called "the ups protected space"

The UPS is either an inverter/charger/with automatic transfer switch + battery
or
an inverter + discrete AC charger + battery

The UPS gets power from a circuit outside of the UPS protected space
The fuse for the UPS protected space is removed
The UPS protected living space is energized via
a suicide cord from the inverter to an outlet in the UPS protected living space

The neutral ground bond is somewhere beyond my control upstream of my fuse box

With the inverter/charger in passthrough(transfer switch) mode
will I have problems with multiple neutral paths?
With the inverter/charger running in battery mode
will I have problems with multiple neutral paths?
With the inverter and discrete charger
will I have complete galvanic isolation for the UPS protected space?

I have an idea for a test...
If I have a gfci outlet in the UPS protected space
and I can run a load without tripping the outlet breaker
then things are good right?


I have a similar scenario...trying to run some of my house with off-grid solar without the hassle of grid-tie/permits.

I was going to move the circuits I want into a critical load panel, then run that off solar/battery only switching to grid in a low voltage situation.

I came across this transfer switch which I think will do what I want.

Apologies if I misunderstand your end-goal...but the transfer switch may be of interest nonetheless.
 

smoothJoey

Ooga Booga!
I came across this transfer switch which I think will do what I want.

The transfer switch you reference works opposite of what I want.
It only goes to mains power when the battery voltage goes low.
The transfer switch is part of the inverter charger in my scenario.
Which is not mandatory, I mostly consider it because the inverter/chargers seem to be less expensive than the discrete components.
 
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SolarRat

Photon Sorcerer
The transfer switch you reference works opposite of what I want.
It only goes to main power when the battery voltage goes low.
The transfer switch is part of the inverter charger in my scenario.
Which is not mandatory, I mostly consider it because the inverter/chargers seem to be less expensive than the discrete components.

It can be wired either way. You can use grid as your default and if the grid fails it will switch to battery fast enough for electronics to not even notice. I just thought it was a cool device for the price with various uses...
 

Craig

Watts are Watts!
Staff member
Moderator
If your protected space is switched off from main all should work. I'm wondering if you can detach neutral as well just to be safe.
 

smoothJoey

Ooga Booga!
If your protected space is switched off from main all should work. I'm wondering if you can detach neutral as well just to be safe.
Nope, the neutral ground bond is out of my suite.
The fuse for that protected space circuit is removed from my suite's panel which isolates the hot.
 
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JeepHammer

Photon Sorcerer
Break out tabs, separate the sockets from each other...

1579822060917.png

Emergency Power from inverter or small solar outlet where you can use it.
One or two for emergency power, like behind the fridge if you know what I mean...

1579822339494.png

Or,
Make it as easy as moving the plug from one outlet socket to another...

1579822167779.png

I do recommend you paint the face of the inverter outlet so you know which is which.


1579822243102.png

Or,

1579822429571.png

1579822480584.png

Or,

Grid, Generator, Bigger inverter when you need a bunch of power, ect.
But don't want the big losses all the time with a big inverter mostly idle...

1579822581949.png

Now, I'm showing 15 Amp breakers, but that will depend on the output of inverter and wire size.
15 Amp is what I had graphics made for, so that's what you get.
 
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jasonhc73

Cat herder, and dog toy tosser.
If you have no switch at the main load's panel, do not attempt.

I use a 4P 225 amp Knife switch to change from Grid to Off-Grid mode.

I thought about making "green" plugs all over the house, and then I realized just how much work that is. Every time you switch over to the "protected" circuit, you have to go plug everything into the protected circuit.

In the Knife Switch setup, I have a massive circuit, like a NEMA 14-50 stove circuit, that I can back feed. This only works when you can disconnect the mains at the load's panel.

My load's panel has two inputs now. Potential for complete destruction exists. If I supply my house with both sources, the off-grid inverters die instantly.

Normally a Knife switch is for switching between two inputs to one output. I have it differently. I have the SOURCE (the house) either supply the inverters to the inverters INPUT or switch the house to the inverters OUTPUT. It sounds complicated, but it is very simple to hook up.

What does this accomplish? My entire house is wired already with its wiring. I just use it from source A or source B. Practically identical to a whole house generator, but not with an expensive auto switch. The drawback is I have about a 1-minute wait between changing sources. I have to wait for the inverters to discharge and turn off. Stuff in my house that I don't want turning off, I have a simple Cybertron UPS that kicks on instantly, so I don't have to worry about losing the WiFi or the computers.

 

JeepHammer

Photon Sorcerer
If you have no switch at the main load's panel, do not attempt.

I use a 4P 225 amp Knife switch to change from Grid to Off-Grid mode.

I thought about making "green" plugs all over the house, and then I realized just how much work that is. Every time you switch over to the "protected" circuit, you have to go plug everything into the protected circuit.

In the Knife Switch setup, I have a massive circuit, like a NEMA 14-50 stove circuit, that I can back feed. This only works when you can disconnect the mains at the load's panel.

My load's panel has two inputs now. Potential for complete destruction exists. If I supply my house with both sources, the off-grid inverters die instantly.

Normally a Knife switch is for switching between two inputs to one output. I have it differently. I have the SOURCE (the house) either supply the inverters to the inverters INPUT or switch the house to the inverters OUTPUT. It sounds complicated, but it is very simple to hook up.

What does this accomplish? My entire house is wired already with its wiring. I just use it from source A or source B. Practically identical to a whole house generator, but not with an expensive auto switch. The drawback is I have about a 1-minute wait between changing sources. I have to wait for the inverters to discharge and turn off. Stuff in my house that I don't want turning off, I have a simple Cybertron UPS that kicks on instantly, so I don't have to worry about losing the WiFi or the computers.


That's pretty cool!

I want the Tesla/Frankenstein open throw switch you get sparks from!

<div class="tumblr-post" data-href="https://embed.tumblr.com/embed/post/Li6NtW4O3NHi5FHiYyMbRw/173470906858" data-did="da39a3ee5e6b4b0d3255bfef95601890afd80709"><a href=" https://giantmonster.tumblr.com%2Fpost%2F173470906858 "> https://giantmonster.tumblr.com%2Fpost%2F173470906858 </a></div> <script async src="https://assets.tumblr.com/post.js"></script>
 

jasonhc73

Cat herder, and dog toy tosser.
That's pretty cool!

I want the Tesla/Frankenstein open throw switch you get sparks from!

<div class="tumblr-post" data-href="https://embed.tumblr.com/embed/post/Li6NtW4O3NHi5FHiYyMbRw/173470906858" data-did="da39a3ee5e6b4b0d3255bfef95601890afd80709"><a href=" https://giantmonster.tumblr.com%2Fpost%2F173470906858 "> https://giantmonster.tumblr.com%2Fpost%2F173470906858 </a></div> <script async src="https://assets.tumblr.com/post.js"></script>
That entire orange plastic cover is there to keep the spark inside! I've thrown it a few times, and if I keep doing it, it's going to weld itself togethor some day!

 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Seems to be so complicated but....

Take one "sub-panel" like a Square-D Q06 and put the circuits you want on the UPS in it.
Feed to the 120V circuit sub-panel from an Inverter/Charger like a Samlex which has ATS built in.
Set the priority to Battery 1st, Grid 2nd, Genset 3rd.
Feed the Grid Line to Inverter from the regular house AC via a HD timer switch (on @ low peak hours) with manual override
Feed the Solar Controller port via a solar controller capable of up to 50A output.

Maybe too much KISS applied to be obvious but....
 

SolarRat

Photon Sorcerer
That entire orange plastic cover is there to keep the spark inside! I've thrown it a few times, and if I keep doing it, it's going to weld itself togethor some day!



That video is a must see for anyone thinking of using AC switches/relays on DC!
 

Red Squirrel

Solar Enthusiast
Here's what I would do:

Rectifiers(AC/DC power supply) -> batteries -> inverters.

Rectifiers are powered by commercial AC, inverter powers the backed up panel. You can then charge batteries with solar too, the rectifiers just need to kick on if voltage is too low.

That way you're not dealing with weird backfeeding stuff and there is zero switch over time to go to commercial AC.
 

jasonhc73

Cat herder, and dog toy tosser.
Here's what I would do:

Rectifiers(AC/DC power supply) -> batteries -> inverters.

Rectifiers are powered by commercial AC, inverter powers the backed up panel. You can then charge batteries with solar too, the rectifiers just need to kick on if voltage is too low.

That way you're not dealing with weird backfeeding stuff and there is zero switch over time to go to commercial AC.
Isn't this exactly what a UPS does?

This is how I would like to see the future of all solar with A/C microinverters:

Panels -> A/C microinverter -> Rectifier (ACtoDC) -> Batteries -> Inverter (DCtoAC) -> House

How I see how a UPS works.
A/C source -> Rectifier (ACtoDC) -> Batteries -> Inverter (DCtoAC) -> Loads output

Change A/C source to (Grid/Micro-Inverter/Generator), Change loads to (Critical loads/backup loads/protected, or simply the entire house)

Now the philosophy of this.
The vast majority of society does not have the means to afford this, or the technical skills to implement. An off-grid setup can cost as little as 5 years of utility bills, to as much as 20 years of utility bills. But that's it.

After the initial outlay, the production continues far longer than the end of the utility bills. Consider the very next month after the installation of any solar system, the cashflow is a net positive. That means the very next month, the wealth of the individual is positive. Instead of giving money to the utility, you keep that money or have the ability to spend it on other things that make you happy.
 

offgriddle

"FOREVER BEGINNING"
DON'T TRY THIS AT HOME!

Scenario
Half my living space is on one 15amp fuse

The plan is to put that living space on UPS
this space shall be called "the ups protected space"

The UPS is either an inverter/charger/with automatic transfer switch + battery
or
an inverter + discrete AC charger + battery

The UPS gets power from a circuit outside of the UPS protected space
The fuse for the UPS protected space is removed
The UPS protected space is energised via
a suicide cord from the inverter to an outlet in the UPS protected space

The neutral ground bond is somewhere beyond my control upstream of my fuse box

With the inverter/charger in passthrough(transfer switch) mode
will I have problems with multiple neutral paths?
With the inverter/charger running in battery mode
will I have problems with multiple neutral paths?
With the inverter and discrete charger
will I have complete galvanic isolation for the UPS protected space?

I have an idea for a test...
If I have a gfci outlet in the UPS protected space
and I can run a load without tripping the outlet breaker
then things are good right?
Take a pencil and paper and draw it out, this is not an Uber complicated scenario. Enjoy.
 

offgriddle

"FOREVER BEGINNING"
That's pretty cool!

I want the Tesla/Frankenstein open throw switch you get sparks from!

<div class="tumblr-post" data-href="https://embed.tumblr.com/embed/post/Li6NtW4O3NHi5FHiYyMbRw/173470906858" data-did="da39a3ee5e6b4b0d3255bfef95601890afd80709"><a href=" https://giantmonster.tumblr.com%2Fpost%2F173470906858 "> https://giantmonster.tumblr.com%2Fpost%2F173470906858 </a></div> <script async src="https://assets.tumblr.com/post.js"></script>
A sense a humor indicates an abundance of intelligence, no sense of humor indicates a lack of intelligence. Keep smilin man, WTG!
 

JeepHammer

Photon Sorcerer
A sense a humor indicates an abundance of intelligence, no sense of humor indicates a lack of intelligence. Keep smilin man, WTG!

Humor doesn't come across very well on the internet for some reason, someone always takes it the wrong way.

That scene always reminded me of when I was 7 to 15 years old, I built a BUNCH of Tesla coils and Jacobs Ladders, when EVERYTHING had a big transformer with lots and lots of lacquer insulated bell wire in them, the dumps were full of them and I was a salvaging fool!
If you could lay hands on a big neon sign transformer, that was GOLD to a DIY builder wanting to make electrical arcs.

If you have ANY interest in things like Jacobs Ladders and Tesla coils, I suggest you download this book and have a look...
You might be surprised how easy this stuff is to build.
.pdf link https://books.googleusercontent.com...7sLKYKZuy6KN5YD-B-lxo5uDC1Rfj2k0VeSSO_Q7Hk8dT

I got my first copy about 6 years old and learned to read so I could build this stuff!
I used to make crystal radios & some of the other stuff, nice finished hardwood, bright brass thumbscrew terminals, etc and sell them at antique fairs to get my business started when I first got disabled, I could build this stuff from a wheelchair.

No one does 'Kids Crafts' like this anymore, probably liability issues (You'll burn your eyebrows off kid!)
And today's generation can't look up from the cell phone long enough to do anything creative/constructive...
 
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