Two GFCI Circuit Breakers in One Subpanel

Jump to latest Follow Reply
cmac

cmac

Member
Feb 17, 2019
13
Central Florida
Hello, new to this forum and really like it!

I just purchased a new Siemens QF220A Ground Fault Circuit Interrupter, 20 Amp, 2 Pole, 120V, circuit breaker to replace the existing non-GFCI 20 Amp, 2 Pole, 120V for a new Pentair Intelliflo VS pool pump.

When I opened my sub-panel I noticed there was already a GFCI 15 Amp, 1 Pole, 120V breaker installed for the pool light. The instructions for installing the Siemens QF220A Ground Fault Circuit Interrupter, 20 Amp, 2 Pole, 120V, circuit breaker require only one GFCI connect to the common neutral bar at a time.

Not sure what to do at this point as both breakers need to be GFCI. Is there a certain way to wire the two GFCI breakers together? Added a picture of the sub-panel.

Thanks in advance,
CMAC IMG_4102.JPGIMG_E4100.JPG
 
Last edited:
That makes no sense. Multiple GFCi breakers are often installed in a panel.
 
Mac,

Something is not right... I have several GFCI breakers and they all have their "pig tails" connected to the same neutral bus... :scratch:

I suspect we are reading the instructions wrong...

Let's see what one of our electricians has to say..

Thanks,

Jim R.
 
@cmac Can you post a pic of the instructions where it says that? I could not find anything on the net.

What you should not do is have two GFCIs on the same circuit. That is different then in the same panel for different circuits.
 
The instructions might say not to connect two neutrals to the same terminal, but I don't think that it says not to connect two to the terminal bar.

In other words, one screw for each neutral.
 
Hello, good morning,

Line 7 of the installation instructions says: "Check wiring to ensure that there are no shared neutral connections."
Not sure exactly what that means and how to wire the GFCI breaker as there is only 3 wires going to the pool pump. 2 loads (black) and 1 green (ground).

Do I just place the GFCI white pig tail to the panel neutral bus bar (like the pool light GFCI breaker) and the 2 (black) load wires to the load terminals on either side of GFCI breaker? Nothing in the middle? There is not a white load neutral wire going to or from the pool pump.

New at the wiring part but excited about the new VS pool pump running.
 

Attachments

  • IMG_4108.JPG
    IMG_4108.JPG
    385.4 KB · Views: 8
Shared neutral is a situation where you have two load wires going to different devices and sharing one neutral wire. A GFCI can’t monitor the current difference between wires for each device and will not function properly.

A 240V pump circuit does not have a neutral wire. The GFCI white pig tail still needs to be connected to the neutral bar.
 
  • Like
Reactions: MyAZPool
Allen is correct. That statement is talking about two loads sharing a neutral. There are a few situations where two separately powered loads share a common neutral. It's pretty rare, but it does happen and that's the reason for the warning.
 
Thanks, got it now. There is only one load line going into the j-box coming from the house main panel on a 30 Amp 2-pole breaker.

I'm planning to add a third regular 15 Amp breaker to the j-box for a Pentair SolarTouch unit. Do you think I should replace the 30 Amp breaker at the main for a 50 Amp breaker? All together the J-box will have two 15 Amp 1-pole breakers and one 20 Amp 2-pole breaker.

CMAC
 
Last edited:
The 30 amp breaker in the main panel should be sized to protect the wire ran from it to the sub panel, so without knowing the wire size and length, we can't recommend increasing the size of the 30 amp breaker. And we actually also need to know the rating of the sub-panel (though it's most likely at least a 50 amp rated bus).
 

Enjoying this content?

Support TFP with a donation.

Give Support
Okay, the length is 34 feet from the main to the sub panel (same side of house). The sub panel is a Siemens W0408ML1125U Outdoor Main Lug Load Center, 125A, 4 Space, 8 Circuit. The wire size I don't know but there is a photo of the wire going into the sub panel from the main. How would I determine the gauge size of the wire coming from the 30 Amp breaker at the main panel?
 
Last edited:
282C02DF-DDF5-40DE-98DE-9C1AEFF82B2C.jpegWire gauge required depends on max current and length.
 
Above 10 AWG you have multiple strands.
 

Attachments

  • CFD864E9-D27F-448C-A3FC-B80B3BF4A074.jpeg
    CFD864E9-D27F-448C-A3FC-B80B3BF4A074.jpeg
    131.6 KB · Views: 4
I got distracted with this work thing and you posted before I got back to it, but...

The wire size will be written on the sheath somewhere, but just from the looks of it, it's probably #10 awg so it's only good for 30 amps. I wouldn't change the breaker unless you can also change the wire.

P.S. You can get #8 and #6 in solid conductor, but Allen is correct that most of the time they're going to be stranded.
 
Thanks, I think I'll be fine since the only devices on that 30 Amp line from main to the sub panel will be Intelliflo VS 240v 3 HP pump - Full load 16 Amps, a 120v pool light incandescent - 4 Amps (will upgrade to LED in near future) and a SolarTouch control unit wired as 120v - 0.4 Amps.
 
Last edited:
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply