I have a sub-panel supplying an in-law apartment. The sub is attached to the main panel via 50-amp breaker. I recently upgraded some breakers in the sub-panel to AFCI breakers. They are Siemens brand ( so is the panel ) and require the pig-tail to also be attached to the neutral bar, this is in addition to the branch neutral also being attached to the neutral bar. For these breakers, the neutral is not fed into the breaker like other AFCI breakers. So each AFCI Siemens breaker needs two neutral positions. This has led me to run out of lugs on the neutral bar. What are my options? Currently they are double-tapped which can't stay.

  • Is an expansion neutral bar with isolation risers and a heavy gauge insulated wire to the first neutral bar my best option?
  • Are those pigtails not carrying a load and i can double-tap them like i could for a ground?
  • Is my panel over-stuffed and i need a new panel? pic 1 panel 1 pic 3

edit: best picture i have of inside label: panel label

  • Can you upload a picture of the label, usually inside front cover? Commented Jan 2 at 0:52
  • @manassehkatz-Moving2Codidact added pic, catalog number is: E0816ML1125F
    – browep
    Commented Jan 2 at 0:59
  • That's the left half of the label. Not likely, but check/confirm that the Neutral doesn't have some 2-wire option like Ground has: "One #14-#4 or Two or Three #14-#10 AWG". Commented Jan 2 at 1:17
  • details for using the neutral bar appear to be at the top of the next column of text
    – Jasen
    Commented Jan 2 at 14:13
  • @manassehkatz-Moving2Codidact panel label: assets.new.siemens.com/siemens/assets/api/…
    – Jasen
    Commented Jan 2 at 14:20

2 Answers 2


The instructions state that the PLUG-ON version (QTAN as opposed to QTA) does not have neutral lugs.

"Siemens CAFCI Plug-on breakers now have a single load lug(s) only."

They appear to make no comment about the pigtail version being made that way.

Pigtail wiring diagram from instruction for OTA breaker

The instructions show the pigtail version having the load neutral connect to the device.

I can't find a picture that actually shows the details of the pigtail area on the pigtail device, nor a clear diagram of the device connections as is available for the dual-function GFCI/AFCI breaker.

But I think you might have overlooked a detail of the pigtail device, perhaps due to poorly written instructions. Between poorly written instructions and lack of images showing the area of interest, I can't get any closer than that to the solution, but it's STRONGLY suggested by the wiring diagram for the pigtail version as contrasted with that for the plug-on version (below).

Plug-on neutral diagram

Quote and image source

  • Looking closely at the labeling on the dimension drawings in the brochure, there is no labeling for a load neutral on the breaker, just line, load, and the neutral pigtail, which indicates to me that there's no load neutral lug on the breaker itself Commented Jan 2 at 14:18

By my count from a picture at Home Depot:

neutral bar

you should have 13 neutral screws. That is enough for 2 each for the existing AFCI breakers, 1 for the double-breaker and 2 more in case you put an AFCI in the last spot. You'll have to pop off the top right 2 breakers to access some of those neutral screws, but they're there.


The top 4 AFCIs are actually double half-size breakers. Which means potentially 3 (2 for the circuits plus 1 to power the AFCI) = 4 x 3 = 12 + 1 for the lower-left double breaker + 1 for the lower right AFCI/GFCI (that one gets neutral to the breaker and pigtail to the neutral bar) = 14. 14 > 13. So you may still have a problem...

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