Does NEC code allow this? Solar and generator as S2?

[TheEquineFencer]

Here's the layout as built.

200A service coming into a breaker panel through the wall of the shop. (back to back).

Loads are:

1 20A septic tank pump on a circuit by it self.
2 20A circuits inside, shop lighting split between the two circuits, total of 13 Tandem T8's (4 tubes each fixture)
1 20A lighting circuit outside. 2 2 tube T12's
1 20A office has dedicated for computer.
1 20A office has lighting and receptacle circuit
1 20A bathroom circuit
2 50A 2 pole circuits run to VFD's for lathe and mill, 1-1/2 hp mill and 2hp lathe (3ph) motors
1 30A 2 pole hot water cicuit
1 50A 2 pole circuit for air compressor (31.1A FLA)
2 50A 2 pole welding circuits (two separate receptacles)
2 20A shop wall receptacle circuits.
2 20A circuits for Wood fired hot water heater (one runs just a blower fan, (Maybe 2-3A max), the other runs the pump and controls for the inside of the building 12A max maybe. These could be rewired into one circuit.

All wiring is sized for the breaker.

I may be getting two 3PH 480V 40A ATS that I'm going to reconfigure for 1PH 240V.

Here's where the major problem comes in. I have a Solar Array, a small one right now (1200W) I'm just charging batteries with for now. I have a 3000W or maybe larger up to a 9000W array I'm going to build, plus I have a generator I'm reconfiguring from 3Ph to 1Ph, it'll be 20KW on 1Ph. I'd like to install the the ATS with utility power as Source 1 on one ATS and as Source 2, run the Solar array/Battery bank inverter for power. I'd power the main part of the shop off it, less the air compressor, VFDs and welding circuits. I'd put the second ATS with Utility as Source 1 and the generator as Source 2 and power the air compressor, VFDs and welding circuits from the second ATS. I'd start the generator when I wanted to run them instead of using utility power.

I can leave some of the loads in the main panel and just run what I can through the ATSs if needed.

Unless I switch to the ATSs to "test" I'd stay on Utility power. I'd put the HWH on a timer so it would only work during daylight hours so the Array can run it in daylight. If the Source 2 goes under voltage it'd switch back to Source 1. Basically, I'll be using Utility power as a back up for the most part.

Probably 90% of the time my loads are lighting. I'm also going to (10) 150W equivalent 24VDC LED lighting inside the shop and I'm going to use the 13 Tandem T8's as a back up as needed.

How much load can I put on each ATS?

Can I run solar and a generator as Source 2 through two separate ATSs?

How do you do actual calcs for the loads? The shop lighting is wired on (2) 20A circuits (6) lights on one circuit and (7) on the other, but I think the fixtures only pull about 1.2A max each.

I guess if I consult the AHJ and they bless it I can huh? What does NEC allow?

And no, so far I do not have a ton of money ******* in all this stuff.

I bet this is going to be a good thread to start off with...

 

[Kevin Essiambre]

I would keep the septic pump circuit on with utility power with it's own relay to go to generator power or solar shoukd the power fail, but that's completely backwards of what you're trying to accomplish, and it's a personal preference more than anything.

You'll need a second panel for your large loads if you plan on separating them to run on separate power from the rest. Do you have room beside your current panel for another panel?

You plan on reconfiguring a transfer switch to another voltage... where does the controller get it's power? You may need to change a transformer or install a transformer for the control board. But it sounds like you've got a plan already

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[W-Cummins]

Your 40 amp ATS's will as the name depicts, will run 40 amps of load. If by chance your converting an Onan/Cummins switch I may have the parts to switch from 480v to 240v. With a Onan switch you can also set it up for gen to gen on one of the switches and use the PV source as a gen input, I'm sure other switch manufactures also have this too.


William....

 

[TheEquineFencer]

Your 40 amp ATS's will as the name depicts, will run 40 amps of load. If by chance your converting an Onan/Cummins switch I may have the parts to switch from 480v to 240v. With a Onan switch you can also set it up for gen to gen on one of the switches and use the PV source as a gen input, I'm sure other switch manufactures also have this too.


William....

Yep, they are Onan OT 40's.

I haven't had time to look for a service manual and such for them yet. I wasn't sure, and didn't think the linear actuator was the same on a 480 as the 240. I couldn't remember if it was just a matter of retapping the transformers for the controls or if it need a different set of transformers. Please enlighten me, it's been several years since I've actually converted one.

I was wondering about using a set up transformers if I knew the load rating/amps needed for the actuator and feeding the control power through one for S1 and S2 sensing and operation.

The guy that has them has a 20KW 3ph, I think it is an EK series, that he wants to switch to 1ph, I may try to "barter" him out of the two ATSs. He didn't realize they were 480 3ph when he bought the generator and switches.

 

[W-Cummins]

Ok that changes things


So those switches are a different case
That switch is actually rated 40-125 amps and the guts are the same for the 40, 70, and 125amp models. Cummins just puts a different label on them! That said I'm not sure that they will "Sell" you another label, and if your setup is inspected you may have a hard time convincing the inspector it's a higher rated switch....


The conversion requires a "Kit" that contains the motor, capacitor, and a circuit breaker. The kits are $pendy @ around $400 each. I too thought about using a control transformer to run the motor but gave up when I found some one that had converted a 480v to 240v and had the parts.


William....

 

[brewchief]

Am I understanding that you want run a generator to provide power instead of using utility power?

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