single phase critical load panel vs 240v split phase panel

[byteharmony]

I have a friend who only has 120v critical loads. I'm looking at the EG4 single phase hybrid inverter

For the loads would I just get a normal split phase panel at a hardware store and wire the hot to both busbars?

Is that a code issue / would that pass code inspection? If not, how would you do a 120v system load center?

 

[pvgirl]

Not a code issue just follow 710.15(C):

​

(C) Single 120-Volt Supply​

​

Stand-alone and isolated microgrid systems shall be permitted to supply 120 volts to single-phase, 3-wire, 120/240-volt service equipment or distribution panels where there are no 240-volt outlets and where there are no multiwire branch circuits. In all installations, the sum of the ratings of the power sources shall be less than the rating of the neutral bus in the service equipment. This equipment shall be marked with the following words or equivalent:

WARNING:
SINGLE 120-VOLT SUPPLY. DO NOT CONNECT MULTIWIRE BRANCH CIRCUITS!​

The warning sign(s) or label(s) shall comply with 110.21(B).​

 

[Hedges]

Inverters can fail, so if grid or generator is also available, plan for a bypass mechanism.
This could mean feeding both L1 and L2 through a 2-pole breaker, with inverter feeding both poles of breaker. The breaker can be interlocked with another breaker from the other source allowing 120/240V if available. Or that one can feed just 120V if desired.

 

[byteharmony]

Not a code issue just follow 710.15(C):

​

(C) Single 120-Volt Supply​

​

Stand-alone and isolated microgrid systems shall be permitted to supply 120 volts to single-phase, 3-wire, 120/240-volt service equipment or distribution panels where there are no 240-volt outlets and where there are no multiwire branch circuits. In all installations, the sum of the ratings of the power sources shall be less than the rating of the neutral bus in the service equipment. This equipment shall be marked with the following words or equivalent:

WARNING:​

SINGLE 120-VOLT SUPPLY. DO NOT CONNECT MULTIWIRE BRANCH CIRCUITS!​

The warning sign(s) or label(s) shall comply with 110.21(B).​

So yes?
Just use a Power Distribution Block or Polaris or ? to be able to wire the hot to both of the 120 legs on the load center?

side note @pvgirl love your profile stuff .

another side note: Was struggling with googling a "Power Distribution Block" for 4/0 dual meter (revenue and export) system. Found an amazing post here and @pvgirl is on that one too .

Inexpensive 200 Amp 3-Pole Distribution Block for 4/0 Cable

I've read no so great stories about using Polaris connectors about how they loosen up over time. I have a manual transfer switch and I need a 3 pole tap. Watching Engineer775 Youtube videos, he has been using some nice distribution blocks. I believe they are Mersen: I've seen distribution...

diysolarforum.com

Inverters can fail, so if grid or generator is also available, plan for a bypass mechanism.
This could mean feeding both L1 and L2 through a 2-pole breaker, with inverter feeding both poles of breaker. The breaker can be interlocked with another breaker from the other source allowing 120/240V if available. Or that one can feed just 120V if desired.

This is a rabit hole that I'm actually pretty excited about. I'm just wrapping up my Sol Ark 15k install at home. $10k I paid for my sol ark.

Now of course there is the 18k from EG4 $5k

Using my head, my education, my experience, google and this form < $1000

So real numbers.
Solar Start: $4,602 is what you could buy to get started with solar, your power bill will go down.
Next Add backup: $2,700 this is the 120v system for critical loads you could buy with the savings from solar start
Next Add generator: $850 this is the 120v system backup you could use for when it's dark / your battery is too small

The generator, 48v batteries and 120v all in one could be swiped for camping / portable power needs / save a friends life.

To get more power just parallel stuff. To get 240v split phase start w/ 2 EG4 units.

Diagram and cost estimates attached. Sorry a little messy, I really gotta get back to work. I just really appreciate you guys on the form answering so I took the crazy in my head and put it on paper.

 

[pvgirl]

So yes?
Just use a Power Distribution Block or Polaris or ? to be able to wire the hot to both of the 120 legs on the load center?

Yup that easy.

 

[Hedges]

If no one was looking, I'd just slip a second wire in the screw terminal and daisychain.
But we're not supposed to put two wires under one screw. Except for connectors where that approach is UL listed.

So I'd strip insulation off middle of wire, either feed it through on connector, daisy chain to next, or twist into a pigtail stub and insert in the first connector. I've used that feed-through approach to put two circuit breakers downstream of a safety switch.



If you use a generator input plug, you can set that up as L1/L2/N/G and feed it from either 120V inverter or 120/240V split-phase source. Do the paralleling of L1/L2 in the cord from inverter. Similar if you set up interlocked breakers and hard-wire the source.

 

[byteharmony]

Right on!!!

The more I think about this approach the more I like this!

My buddy can start anywhere the pain is the greatest:

1. Power bill: Solar
2. Backup: Critical load panel and generator
3. Mobile / Camping: All in one solar w/ camper panels and battery.

The vision to assemble allows for a lot of scalability. The devices in use are small enough that simple plugs could be used to move equipment from a trailer to a home:

AC: Nema 7-50P / 7-50R
DC: XT90 with resistive arc connection protection

We could even use the twist lock AC to start with as the manual transfer switch to avoid that hardware .

Thank you so much, my buddies should love this stuff .