choosing breaker for main AC panel connection to Radian

Discussion about OutBack Inverters in Grid Tie Applications

Moderators: OutBack, OutBack Moderator Team

Post Reply
User avatar
Megunticook
Forum Guru
Posts: 242
Joined: Fri Sep 29, 2017 4:08 am
My RE system: 6.4 kW solar array (21 QCell 305 panels in strings of 3)
GS8048A FLEXpower Radian (Radian 8048A, 2 FlexMax 80 cc's, Mate 3s, FlexNet DC, Hub)
8x6v Rolls-Surette 550 FLA batteries, 428AH
Location: Maine
Contact:

choosing breaker for main AC panel connection to Radian

Post by Megunticook » Fri Nov 17, 2017 4:51 am

What type of breaker should I install in my main AC service panel to connect with my Radian 8048A? Since power will flow in both directions, I'm thinking it will need to be a particular kind of breaker device but in looking at breakers at stores/online it's not clear to me what I need.

Thanks for the help.
https://sunnypower.org

Mike Curran
Forum Emperor
Posts: 1562
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof:
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 repl'd MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied, no longer AC- coupled

Outback Skybox - Barn roof: (2019)
- 14 (2x7) Talesun 275W (DC array input to SB charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W, Enphase M215 modules

All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: choosing breaker for main AC panel connection to Radian

Post by Mike Curran » Fri Nov 17, 2017 10:29 am

Having power flow in both directions doesn't require a special type of breaker. A normal breaker sized at no greater than the AC input capacity (amps) of your 8048a will work.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

User avatar
Megunticook
Forum Guru
Posts: 242
Joined: Fri Sep 29, 2017 4:08 am
My RE system: 6.4 kW solar array (21 QCell 305 panels in strings of 3)
GS8048A FLEXpower Radian (Radian 8048A, 2 FlexMax 80 cc's, Mate 3s, FlexNet DC, Hub)
8x6v Rolls-Surette 550 FLA batteries, 428AH
Location: Maine
Contact:

Re: choosing breaker for main AC panel connection to Radian

Post by Megunticook » Fri Nov 17, 2017 10:57 am

Thanks.

So I take it the breaker should be installed at the bottom of the service panel bus? My grid service connects to a main 100A breaker at the top.
https://sunnypower.org

User avatar
Jorge Guzman
Strategic Platforms
Posts: 248
Joined: Thu May 29, 2014 9:44 am
My RE system: VFXR3524A, FM80, MATE3. 3x 260W REC. 4x Trojan L16 FLA 370Ah.
Location: Arlington, WA

Re: choosing breaker for main AC panel connection to Radian

Post by Jorge Guzman » Fri Nov 17, 2017 12:50 pm

On a load side tap, Per NEC 690.17(A) the breaker must be suitable for backfeeding. Typically if the breaker is labeled with Line and Load they have only been tested in one direction and not recommended for grid-tie systems.
Jorge Guzman
Sr. Strategic Platforms Analyst


Watch easy to follow video tutorials:
https://www.youtube.com/c/wattschool

User avatar
Megunticook
Forum Guru
Posts: 242
Joined: Fri Sep 29, 2017 4:08 am
My RE system: 6.4 kW solar array (21 QCell 305 panels in strings of 3)
GS8048A FLEXpower Radian (Radian 8048A, 2 FlexMax 80 cc's, Mate 3s, FlexNet DC, Hub)
8x6v Rolls-Surette 550 FLA batteries, 428AH
Location: Maine
Contact:

Re: choosing breaker for main AC panel connection to Radian

Post by Megunticook » Fri Nov 17, 2017 1:05 pm

Do you think one of these would work?

Image

https://www.homedepot.com/p/Siemens-50- ... W906605651

The label on my panel says I'd need a special hold-down kit for any backfed breaker as well. I think I found that also:
Image

One other question. Why does the AC subpanel (critical loads/backup) need a main breaker if there's a breaker already in the GSLC for the inverter's AC output on that circuit?
https://sunnypower.org

Mike Curran
Forum Emperor
Posts: 1562
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof:
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 repl'd MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied, no longer AC- coupled

Outback Skybox - Barn roof: (2019)
- 14 (2x7) Talesun 275W (DC array input to SB charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W, Enphase M215 modules

All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: choosing breaker for main AC panel connection to Radian

Post by Mike Curran » Fri Nov 17, 2017 2:13 pm

Learn something new every day. Sorry for the bad advice.
Photo of my inverter feed breaker below, right side of panel.
1510956963535-779983470.jpg
Nowhere does it say "line" or "load". Don't think it's popping out with the cover on the box
1510957188552-1039487942.jpg
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

foo
Forum Expert
Posts: 72
Joined: Thu Jun 30, 2016 1:25 pm
My RE system: VFXR3524A Inverter
3.7kW Solar Array @48V
24V Battery Bank - 210AH (4x105AH @12V) -FLA
Mate3S
Outback Power FLEXmax FM80 MPPT Solar Charge Controller x 1
Outback Power FLEXmax FM60 MPPT Solar Charge Controller x 2

Re: choosing breaker for main AC panel connection to Radian

Post by foo » Tue Nov 21, 2017 5:26 pm

A breaker suitable for backfeeding.

Anyone got a link to one of those?

Mike Curran
Forum Emperor
Posts: 1562
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof:
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 repl'd MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied, no longer AC- coupled

Outback Skybox - Barn roof: (2019)
- 14 (2x7) Talesun 275W (DC array input to SB charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W, Enphase M215 modules

All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: choosing breaker for main AC panel connection to Radian

Post by Mike Curran » Tue Nov 21, 2017 5:40 pm

My understanding from googling "breaker suitable for backfeeding" is that any breaker whose in and out terminals are not labelled line and load (or load and line :smile: ) are suitable. Mostly it's the breakers that incorporate ground fault and arc fault protection that are NOT suitable.

Some licensed electrician could give the official answer.

- From a do-it-yourselfer. FWIW
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

foo
Forum Expert
Posts: 72
Joined: Thu Jun 30, 2016 1:25 pm
My RE system: VFXR3524A Inverter
3.7kW Solar Array @48V
24V Battery Bank - 210AH (4x105AH @12V) -FLA
Mate3S
Outback Power FLEXmax FM80 MPPT Solar Charge Controller x 1
Outback Power FLEXmax FM60 MPPT Solar Charge Controller x 2

Re: choosing breaker for main AC panel connection to Radian

Post by foo » Wed Nov 22, 2017 12:17 pm

Gotyas. Thanks for the added info.

I'll keep doing some research on it.

EDIT: Here's one to help add weight to your line of thinking;
https://www.schneider-electric.us/en/faqs/FA121271/

Post Reply