Nobody wants to burn. That’s a given, right? And no one wants to see their house go up in flames … or that of their family or friends. Electrical contractors never want to see their customers’ homes destroyed by an electrical issue.

Arc Fault Circuit Interrupters … On Bluetooth!

Steve Maurer, IME
Nobody wants to burn. That’s a given, right? And no one wants to see their house go up in flames … or that of their family or friends. Electrical contractors never want to see their customers’ homes destroyed by an electrical issue.

According to the NFPA website, electrical issues are one of the top four reasons for house fires. Some of the others are cooking, heating, and smoking. Even candles present a significant risk. From 2015-2019, United States fire departments responded to an estimated 7,400 home fires started by candles … each year! This created an annual average of:

  • 90 deaths
  • 670 injuries, and
  • $291 million in direct property damage

But most fires, no matter the source, are preventable. The electrical industry is constantly striving to improve equipment and technology to help prevent fires and physical damage from electrical sources.

Two such pieces of equipment—that are now code requirements in new construction and in some old work situations—are GFCI and AFCI breakers and/or receptacles. While they may look similar, they do serve different purposes.

GFCIs or ground fault circuit interrupters look for differences in the amount of electricity flowing from the source and the amount flowing back. Even amounts as low as 4 or 5 milliamps will open the circuit in about 1/10th of a second or faster. Used around water sources or potentially damp locations (kitchens, bathrooms, outdoors, and laundries), they help keep people from being electrocuted.

So with GFCIs, think hot to ground problems.

AFCIs (arc-fault circuit interrupters) are different and look for a whole other scenario. As the name implies, these devices are looking for arcing in the circuit. The concept here is more fire prevention than shock protection. Arcs generate heat. And heat doth generate … fire!

The picture that quickly comes to mind is a short between a hot and neutral. The first generation branch/feeder AFCI breakers (required by the 1999 NEC) addressed this. They tripped when a parallel arc occurred between hot and neutral.

However, in January of 2008, branch/feeder AFCI breakers were phased out. Their replacement was a combination type AFCI breaker. These breakers sense both parallel circuit arcing and lower level series arcing. A series arc happens along the same conductor or at connections. The neutral isn’t involved. It’s a break in the hot conductor that causes arcs across the break.

This provides protection in the branch circuit wiring and extends to any cords and appliances connected to it at a receptacle.

In other words, if you nick your extension cord (yeah … that happens), either completely between conductors or just the hot, the AFCI device will trip, protecting against overheating.

But wait … there’s more.

AFCI receptacles provide protection beyond the branch circuit to appliances, cords, and any other receptacle downstream from it. You only need the first receptacle to be an AFCI one. But … it also provides protection upstream from any series arcs.

Hot to ground parallel arcs are also detected and protected.

So you get protection from damaged cords, or damage due to nails, screws, and staples being driven into structure wiring. Even loose connections or plugs can be detected when they arc.

So, what’s this “Bluetooth” thing of which I speak?

No, it’s not the Danish King from whom the name derived.

It’s all about the tech.

And … there’s an app for that.

Leviton Outlet Branch Circuit AFCI Receptacles
I’m pretty sure most AFCI receptacles protect against parallel and series arc faults. But the only one I’ve heard of using Bluetooth connectivity to detect both more accurately is the Leviton product.

The receptacle connects to an app that monitors any fault conditions. This allows you to determine if a true fault happened, or if it was merely a nuisance trip. Any trip events can be uploaded to Leviton for evaluation. Updates to the receptacle’s firmware can be downloaded to improve performance and ensure more accurate detection of true arc faults.

Yes, sometimes normal appliance operation and some common electrical loads caused false, nuisance tripping. But as the data collection is improved, so does the arc detection accuracy.

As mentioned, the first AFCI receptacle on the circuit protects everything downstream. But what if the circuit doesn’t have receptacles? Think smoke detectors and most lighting loads. You can install a blank face AFCI to protect those circuits. Another option for lighting loads is to install a combo AFCI and switch. This can be used for modifying existing circuits where a switch is the first in line on the circuit.

As with any protection device, both GFCI and AFCI, testing is essential. If you’re the installer, you may want to teach your customers how to do this. It’s the same procedure for both and is accomplished in just a few seconds per device.
Photo courtesy of Leviton
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