Breaker tripping question

[Marc M]

Hello all... long time. So I do inspections for the CSLB now and looking for a code to help support an issue the homeowner is experiencing.

We have a 20A laundry dryer circuit that is a GFI receptacle and is also on an AFCI disconnect that trips after a few minutes of use.

I just need a code reference that supports and / or states that the circuit is supposed to handle the load? And not trip under normal use? Or something else Im not familiar with?

Sorry if im vague but its the best I can explain I suppose... Im open to questions to help me write this report.
TY
marc

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[Jerry Peck]

I just need a code reference that supports and / or states that the circuit is supposed to handle the load?

Code will only address minimum circuit size for loads, and if the dryer isn't trip the breaker, then the circuit is adequate by code.

Code for GFCI and AFCI do not state that they are suitable, code only states that the protection is required.

And not trip under normal use? Or something else Im not familiar with?

That would be either a dryer issue (something wrong with the dryer, which is likely as the GFCI is tripping) or a GFCI or AFCI issue which would be through the manufacturer of the AFCI or GFCI device (however, I think GFCI device issues were resolved decades ago).

[Marc M]

Code will only address minimum circuit size for loads, and if the dryer isn't trip the breaker, then the circuit is adequate by code.

Code for GFCI and AFCI do not state that they are suitable, code only states that the protection is required.



That would be either a dryer issue (something wrong with the dryer, which is likely as the GFCI is tripping) or a GFCI or AFCI issue which would be through the manufacturer of the AFCI or GFCI device (however, I think GFCI device issues were resolved decades ago).

Thanks buddy

[Dom D'Agostino]

Adding a bit to that, AFCI breakers are still flaky in some new construction homes, but easy enough to troubleshoot (for someone else of course).

[david shapiro]

I'll add some deep background on top of what Jerry and Dom said.
First, here's your code ref, one that may not bring smile crinkles to the corners of your eyes: "90.2 Use and Application.(B), Adequacy. . . . provisions are considered necessary for safety but not necessarily efficient, convenient, or adequate for good service. . . ." One could add to this "90.7: Examination of Equipment for Safety. . . Suitability [of listed equipment] shall be determined by application of requirements that are compatible with the Code." I interpret this as meaning that if the dryer is listed, the NEC requires the listing to confirm that it will work when downstream of protective devices that the code requires for the outlet or area.
Second, troubleshooting could well determine that there's a defect in the wiring or in the appliance. It could cause an overload, a short, or some arcing. Many a slip . . . .
Third, the CB could be misbehaving. Cheap and dirty troubleshooting swaps out the CB with another AFCI to see what happens. If the replacement works, and dries a full load, end of story. If the replacement trips, in goes a thermal-magnetic CB for testing purposes. If that trips, overload or short. If it doesn't, the provisional conclusion is arcing, a.k.a. a load signature the AFCIs don't recognize. This warrants contacting the manufacturer of the appliance, of the CB, or of both bits. At one point, AFCI manufacturers were getting aholt of each set of new appliances so as to update the next version of their AFCIs' firmware.

Now to the deep background:

The drum motor could very well be DC. Even if not, the waveform utilized could be nothing like 60 Hz AC, and this means leakage/capacitor drain current could be spikey and give some AFCIs the heebie-jeebies. Most GFCIs, too. Some AFCIs contain GFCI circuitry, though less so than in the past.

The standard for GFCIs specifies trip/don't trip limits at 50/60 Hz, and is mum about any response to leakage of other frequencies. There is a joint task group in ULSE between UL 101, the horizontal standard limiting appliance leakage, and UL 943, GFCIs, that's been working several years to come up with what probably will be an optional standard for GFCIs that resist high-frequency leakage. But that's not a now thing. (I have my concerns about what's currently proposed, but nothing's final.)

[Bill Kriegh]

Before I retired I used to carry 10-15 AFCI devices for each of the usual suspect manufacturers.

Many times, a constantly tripping AFCI was replaced with one or several different of the same manufacturer devices and eventually one would usually work as advertised. The AFCIs that were removed because they constantly tripped were kept and used in the same process at another location and some would work in that location. The involved circuits included everything from circuits with no loads to various type of loads, but most often laptop type power supplies.

Newer appliances often have a bunch of extra unneeded electronics in them that create a bunch of "noise" that some of the earlier AFCIs evidently had trouble sorting out, This has gotten better over time but it's still possible to get an assemblage of an AFCI and a load that just don't get along and changing either one MAY fix the problem. I often wondered if AFCIs shouldn't have included a port where the "latest and greatest" upgrades to whatever algorithm was making things chooch could be uploaded to them. They seemed to have gotten better over time and eventually wholesale houses quit having large boxes of returned AFCIs sitting around.

Another thing is that 3 phase motors are a cheaper device to build than a single phase and some appliances have variable frequency drives to run this type of motor. Many are as cheap as overseas tech can make them and probably contribute to some of the problems. I'm not sharing my research, just suggesting places to look for issues

I never made enough on a job I could afford to go to a site with analytical equipment and spend hours tracing gremlins that probably didn't exist. I found it more practical to stick with device brands that had the best history with me and carry spares for all types so I could swap. Of course this suggests to me that maybe things weren't ready for prime time when they hit the market

I did find that using staples that weren't completely metallic seemed to make a difference in new work but I don't know if that situation improved because I never went back to all metal staples.

Keep in mind that these are MY experiences and YMMV.

[Dom D'Agostino]

. Of course this suggests to me that maybe things weren't ready for prime time when they hit the market.

I agree with that. And thanks for sharing the useful info.

[Jerry Peck]

Of course this suggests to me that maybe things weren't ready for prime time when they hit the market

I agree with that. And thanks for sharing the useful info.

While I also concur with Bill, I also acknowledge that, regardless how much testing is done, or how large of a test sample one uses, the only real test is to stand up on stage in front of a packed stadium and ... it either works or bombs out and everyone heads to the exits.

Which leaves the real middle ground: it basically works and there is just a lot of moaning, but few head to the exits.

I contend that there was a lot of moaning, but few headed to the exits with AFCI devices ... a LOT of moaning, yes.

[david shapiro]

I often wondered if AFCIs shouldn't have included a port where the "latest and greatest" upgrades to whatever algorithm was making things chooch could be uploaded to them. . . .

Another thing is that 3 phase motors are a cheaper device to build than a single phase and some appliances have variable frequency drives to run this type of motor.

The last I heard about updating firmware, there was talk about doing so remotely. I don't know whether anything came of this.

My (fuzzy) understanding is that the tension is between creating cheaper controls and protecting them by draining noise to ground versus using more expensive methods of protecting electronics and being in a poorer competitive position in terms of initial cost.

[david shapiro]

there was a lot of moaning, but few headed to the exits with AFCI devices ... a LOT of moaning, yes.

The question I have is who headed to the exits, and how easy it was to notice.

Successful TIAs or subsequent-edition backpedaling is easy to check.
Amount of applicable local amendments could be checked, with enormous effort.
Delayed adoption? It's hard to pin this on one item, much of the time.
Inspectors choosing not to enforce requirements? Impossible, other than on the local level.
Finally, there's the under-the-table work; similarly, there's the licensed contractor who, on the first service call, goes back to plain thermal-magnetic protection. Like Bill, he can't afford the time to check waveforms, even if he has the skills and equipment. Unlike Bill he can't be bothered carrying AFCI swap-ins to try.

If there's a considerable groundswell, as there was with GFCIs protection of VSD-driven HVAC equipment, we do see local policy pushing back, followed by successful TIAs.
Otherwise, I just don't know.

[Jerry Peck]

Finally, there's the under-the-table work; similarly, there's the licensed contractor who, on the first service call, goes back to plain thermal-magnetic protection.

The electrical contractor I worked for in early 70s addressed GFCIs this way: put GFCI breakers in to pass inspection. After CO, go back and replace with regular breakers. It was an 'automatic do over' simply to avoid complaints about the GFCIs tripping.

I don't recall when he started giving GFCIs a second chance to see if the issues had been taken care of, maybe late 70s? Possibly about a 5 year period, but I don't recall precisely when.

The first year, maybe two years, was replace GFCIs with GFCIs once, then replace with non-GFCIs. Then it became SOP for the 'do over after CO'.

[Markus Keller]

AFCI's were taken out of our Code in 2017 or 19, don't remember.
GFCI's - around here new sites will install for washer/dryer but then they tend to get taken out pretty quick.

[david shapiro]

AFCI's were taken out of our Code in 2017 or 19, don't remember.
GFCI's - around here new sites will install for washer/dryer but then they tend to get taken out pretty quick.

Dang, Markus. I put both AFCIs and GFCIs ahead of every 120VAC circuit but one when I rewired my house in 2014. The only appliance that couldn't take it--or so the mfg warned--was the air handler. In old work, I can see being leery about nuisance trips, but then older wiring also is where they're most needed.

Does Chi still restrict the use of NM?

[Markus Keller]

Damn skippy
We don't want none of that UL listed extension cord crap in our town. This is the land of conduit. We like having a reliable ground path.

On a more serious side, I don't know that we could safely go to Romex. We have so much poor bad construction here its crazy. As a related example, back in the early 2000's when TJI joists were the new big thing in Irish towers here, it took a while for plumbers to learn they could chop the top or bottom cords of the joist. If we brought Romex in, how many years of unsafe work and fires would it take for people to learn to use it safely.
Do I sound like an old bast... with his head in the sand? Maybe.
PEX for plumbing yes. Romex, hell no.

From a practical standpoint, the average homeowner sees that bare copper wire in Romex and pulls a Homer. In some of the suburbs with less stringent Muni inspections we see the ground conductor cut off in boxes in rehabs and yes even in new construction.
'eez ok I know how do electric'

We don't have enough trade training, it takes too long for knowledge to seep through the general worker population and electrical can kill.