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I just had outlet added last week and breaker upgraded to CAFCI

The electrician forgot to place back the metering clamp for home automation on the circuit, so I went back and I was putting it back, I noticed the pigtail from AFCI to neutral was rather loose not torqued down at all.

How big of a risk was this? I know loose neutral is bad, just not sure how bad is LOSE not connected neutral AFCI pigtail.

I don’t think that pigtail carries load as circuit was working, is it only used for powering AFCI electronics? That would explain why wire was not heating up/arcing.

I torqued it down ( hopefully not too much but pretty tight, now I’m worried that it’s over torqued )

Does this look over torqued ?

Sorry here a link to photo… I just took scrap piece of 12AwG that was by the panel and did “torque” test

Not sure if it’s flattened too much?, I tried to torque it roughly same on actual conductor

enter image description here

enter image description here

And yes electrical will be coming back next week …

Thank you

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  • Where is the load neutral terminated? It should terminate to the neutral terminal of the breaker so that the breaker can detect arcing on the neutral. In this case, the pigtail is carrying load current.
    – DoxyLover
    Sep 19 at 5:10
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    Think you uploaded the wrong picture. If that is a wire, it has been beaten, burnt, and maybe melted.
    – crip659
    Sep 19 at 10:55
  • I have no idea what that's a picture of. No way
    – JACK
    Sep 19 at 12:31
  • @JACK YEAH, seriously, what the heck is that? Probably the OP included a wrong link.
    – George Anderson
    Sep 19 at 14:32
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    It’s obviously a photo of copper wire that’s been squished under a neutral/ground bus bar lug. Which makes perfect sense with the attached “Does this look over-torqued” question. There is no doubt about whet the photo is.
    – nobody
    Sep 19 at 17:30

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A loose connection may make functionally useful contact, or it may not. It's hit or miss. If not, it has a fair chance of arcing, creating tremendous heat, damaging the neutral bar and starting a fire - good thing you just installed an AFCI breaker, which would "hear" that arcing even though it was on the line side of the AFCI, because (science fact) current is the same at every point on a series loop.

Normally, and you should assume this -- the circuit's normal current goes through the GFCI/AFCI pigtail. After all, the circuit's neutral attaches to the AFCI, right? If the circuit's neutral attaches to the neutral bar, then no - the pigtail only powers the AFCI electronics. (This is a feature in some new AFCIs, as 'nobody' discusses.)

It has long been known that correct torque is essential on large wire connections such as feeder. Failures tend to be spectacular and destructive in a costly way. However, science has revealed that small wire connections are equally sensitive to torque.

As such, NEC 110.14 now requires that a torque indicating tool (i.e. a torque wrench) be used to set all torques, even on small screws, anywhere a torque is specified. Torques are specified on panel neutral and ground bars.

The least costly torque wrench of appropriate size (that isn't cheap Cheese junk) is a 1/4" beam-type torque wrench with a bit holder. Beam-type wrenches never go out of calibration. Downside: "the entire device is made of metal" unless you get a non-conductive extension bar for it.

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I don’t think that pigtail carries load as circuit was working, is it only used for powering AFCI electronics?

It depends on the specific breaker. Most (if not all) AFCI breakers to date did require the load neutral to attach to the breaker for monitoring, which means the load neutral current passes through the pigtail (or plug-on neutral connection) and so a good connection of the pigtail is particularly important.

However, not all do. In particular, Siemens has recently introduced a tandem AFCI breaker (Q2020AFCP and others) that uses its neutral connection to power the internal electronics only. The load neutral wire goes to the neutral bus bar.

If you have one of the latter type, properly attaching the pigtail is still important but the failure to do so is unlikely to start a fire as the electronics use only a tiny amount of power (compared to the former case).

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The pigtail from the breaker DOES carry current, the same amount as supplied by the hot. Just because it was loose doesn't mean it wouldn't work. Dangerous, but functional if not too much power is used. Glad you found it and will tighten it up. If I don't have torque specs I go to the German torque scale: "Gut 'en tight" (don't snip me for this it's just a joke).

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    Depends on the breaker. Load neutral does not pass through every AFCI.
    – nobody
    Sep 19 at 17:33
  • The torque spec for the neutral bar will be on the panel labeling. It must be set with using a torque measuring tool, per NEC 110.14.
    – Harper - Reinstate Monica
    Sep 19 at 20:29
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Since the circuit was working and without much load, probably no harm done but eventually, it would start to arc and trip breaker or the circuit would start to malfunction. good you caught this.

Even if you downloaded the right picture there's no way we could tell if it's over torqued. You should have called the electrician back to correct it. If you're going to continue to worry about this, get a torque screwdriver and re torque the connections based on the values for the breaker and panel.

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