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I'm adding new panel connected to my main with a 125 amp breaker. I'm moving some circuits from the main to the new panel and adding one new circuit. The existing circuits use a standard breaker but when i put them in the new panel, i want to replace the breakers with AFCIs. The new panel has the bonding screw removed.

I'm stepping through one circuit at a time until i'm sure my process is correct. When I ran into problems on the new circuit that i added, I disconnected all the outlets except for the first one and still the afci trips as soon as i apply a load. I tested the outlet before applying a load. 120 volts and the neutral and ground are connected with near zero resistance as i would expect since they are bonded together at the main. The AFCI is connected as a standard breaker with the addition of the white pigtail added to the neutral bar.

Couldn't figure out why the new circuit didn't work, so i moved one of my existing circuits from the main to the new panel. to do this, i pulled the wires out of the main, run them into a junction box and use a short wire from the new panel and wire nut them in the junction box. Same results, AFCI blows as soon as load is applied.

MY AFCI breakers are Homeline SquareD 20 amp HOM120CAFIC. The panel is a Reliance PanelLink TTV2010DR and Square D breakers are listed as compatible. The new panel has 1 built in 20 amp breaker. if i hook the circuit up to this instead, everything works fine.

Could use some help on how to diagnose the problem. Thanks.

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    Is the return neutral of the circuit connected to the breaker or the bus bar? How about a picture?
    – Matthew
    Aug 23 at 0:37
  • @Ecnerwal 's instructions about connecting neutral properly are the first step. If that doesn't do it, it might well be that you actually have something "wrong" triggering AFCI. Aug 23 at 2:30
  • thanks, that's exactly what i did
    – brucewol
    Aug 23 at 2:49
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Have to suspect that you are not connecting circuit neutral to the AFCI (same is required for GFCI and Combo types) breaker associated with the circuit.

Circuit to fancy breaker, fancy breaker pigtail to neutral bar. Circuits on fancy breakers do NOT connect to the neutral bar directly - only via the fancy breaker - specifically the fancy breaker that serves that circuit. It will have both hot and neutral connections.

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    yup, that's exactly what i did. years ago i put a gfic breaker in a panel and thought all i needed to do was connect the pig tail to the neutral bar. i completely screwed up and connected the circuit to the neutral bar and not the AFCI. Memory certainly isn't as good as it used to be and actually, memory was never that good at all. Just rewired and all is good. Thanks to both of you for the correct answer.
    – brucewol
    Aug 23 at 2:48
  • @brucewol if this answer has fixed your problem, please click the check mark so others can see at a glance that it's been resolved. That helps people to not spend time thinking about an answer that isn't needed, and it helps others to know that this has a functioning answer to solve their problem
    – FreeMan
    Aug 23 at 18:17
  • yes freeman 9, ecnerwal answered the question with good detail. mathew info was also helpful. somewhat new to slack, please tell me where the check box is indicating a solution. thansk
    – brucewol
    Aug 24 at 3:46
  • @brucewol It should be visible to the left of the question; it will turn greeen when you click it. I think there might be a delay (24 hrs?) before new users can see it. Aug 24 at 15:14
  • thanks, figured it out.
    – brucewol
    Aug 25 at 5:14
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Code requires that when you bring the hot(s) over to a subpanel, you bring neutral over too. It doesn't say anything about ground because you're allowed to leave the Romex fed into the original panel, and just bring hot and neutral over to the new panel, e.g. through a pass-through conduit installed for that purpose. But from comments it sounds like you just brought the whole cable over to the new panel. That's fine too.

For AFCI circuits, connect hot and neutral according to the AFCI instructions.

That should take care of it, based on what I can gather from what you said.

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  • I thought i was clear about the neutral and ground ultimately being connected together at the main, that's why there isn't any resistance. There is no easy way to just move the hot wire over to the new panel. Romex is 2 wire + ground, not a single wire. if it was a unsheathed single wire, then it would need to be thhn and that would require a conduit. so yes, of course i brought over hot, neutral and ground for each circuit.
    – brucewol
    Aug 24 at 3:39
  • @brucewol that wasn't at all clear from what you wrote. When 2 panels are put side by side a common approach is to run one or several conduit passages between them, leave the cables in the original panel, and bring hot+neutral over through the conduit passages. Since there are several legit ways to do it, I couldn't make any assumptions about what you did. However, "The AFCI is connected as a standard breaker with the addition of the white pigtail added to the neutral bar" makes me ask - where is the circuit's neutral wire placed? Did you read the AFCI installation instructions? Aug 24 at 4:26
  • yes, i read the afci . it mostly told me how dangerous everything was. there was a installation diagram that only showed plugging the afci pigtail into the neutral bar. it didn't show either load or neutrral.
    – brucewol
    Aug 25 at 5:30
  • In the beginning of my question, I stated that I was adding a new circuit to the new panel, so there would be nothing to leave in the original panel. for those circuits i was moving, i said i would be adding a junction box to connect to the new panel. I don't have enough experience to say that it is common to just move the hot lead .
    – brucewol
    Aug 25 at 5:47
  • my permit says I would be moving selected circuits to the new panel and all new circuits require i use an afci so i would be required to move both hot and neutral for it to work.
    – brucewol
    Aug 25 at 5:52

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