In a previous article I talked briefly on AFCI’s – Arc Fault Circuit Interrupter’s. Specifically, using combination series + parallel arc fault breakers/receptacles for aluminum wiring – this type of breaker is referred to as CAFCI combination arc fault circuit interrupter. If you missed it here is the ->Link<-. AFCI technology can be somewhat mysterious in how it works. This article was created to go a little more in depth on the subject as many people don’t really know why its important have and when its applicable to use one.
Why is this device important? They help prevent fires!
Searching the internet there are various articles on how fires start due to a fault in a electrical system. In the cases where it was said that arcing electricity was the factor in providing ignition to start the fire a AFCI could have prevented the fire. What AFCI’s do is sense the arcing taking place in the electrical circuit and interrupt the power by turning it off to remove the arc hazard. In laymen’s terms a AFCI is similar to how a GFCI (ground fault circuit interrupter) works but instead of sensing a ground fault it senses a arc fault.
Question: When I run my vacuum sweeper / paper shredder / treadmill / etc. it trips my AFCI. Why is this happening? Eaton’s AFCI has been designed to work with devices with motors that are within the FCC standard for noise. Even though these devices have been manufactured to the FCC’s standards, after frequent use wear within the motor can create noise which trips the AFCI. To mitigate the noise generated by these devices, you may use a surge plug or surge strip. In effect, this filters the noise that the device is creating thereby preventing nuance tripping. This isn’t always a practical solution but gives you a troubleshooting starting point. From there you could try plugging in a similar device to see if the problem continues. At this point you probably need to consult a electrician. Generally it is viewed as a last resort but often replacing the AFCI with a newer model will fix the problem so long as a true fault doesn’t exist. You could very well have a serious problem in which case the AFCI is doing its job. No tinkering is going to fix a wiring problem, hence why this is no longer a DIY type job repair. Alot is at risk… your home, your processions, your life, your families life.
In the beginning…
When AFCI technology was first released back in the later 90’s, many AFCI devices were notorious for nuisance tripping. Ontario was a little bit behind the NEC that the United States uses and didn’t mandate the requirement of AFCI protection until 2012. This is in part because of the nuisance tripping the followed. Many consumers and contractors were so worked up that ESA created a reporting system that could inform manufactures of problems with their AFCI products. This allowed the technology to improve to what is currently being released today. You might be able to go as far to say the early adoptors of the AFCI products of the early 2000’s were guinea pigs.
When should I be using a AFCI?
In 2012, the Ontario Electrical Safety Code required that branch circuits supplying receptacles in sleeping facilities of a dwelling shall be protected by an arc-fault circuit interrupter. In the 2015 edition of the Code, the requirement for arc fault protection has include most general
use receptacles in a dwelling. Kitchens and bathrooms are exempt due to those areas being protected by GFCI’s.
AFCI protection is needed all over in new homes, it’s needed any time new outlets are installed, and I expect the requirements for AFCI devices to keep expanding until everything is AFCI protected.
AFCI Construction types
There are 2 main types of AFCI’s. The Combination Type CAFCI and the Branch/Feeder AFCI which differs in its ability to detect series arcing faults. The Branch/Feeder AFCI can only detect line-to-neutral and line-to-ground arcing faults.
Combination CAFCIs provide protection against the high-energy parallel (line-to-neutral and line-to-ground) arcing and low-energy series arcing. “Combination” does NOT mean an AFCI + GFCI. Combination = parallel + series arcing. Combination AFCIs protect downstream branch circuit wiring, loose, broken cord sets, and power supply cords. Here is the take away. The CAFCI is the newer of the 2 technologies and provides the most protection as it has a wider range of faults that it can detect.
Operating and testing a AFCI
Question: What does the test button do on the AFCI device?
All GFCI & AFCI products are equipped with a test button, marked “TEST”. This allows the user to check the functionality of the breaker/receptacle. Pushing the TEST button creates a test fault within the AFCI causing the unit to electrically open the circuit. Underwriters Laboratories (UL) & Canadian Standards Asso. (CSA) agree the best way to check the operation of a GFCI or AFCI is to push the TEST button. Both suggest the AFCI/GFCI be tested monthly, and require a TEST Reminder on adhesive paper and a TEST Schedule with a minimum of 180 check squares on adhesive paper, be included with each breaker to be attached to the residential panel.
While CAFCI breakers are a bit more expensive AFCI breakers. AFCI breakers are still more expensive then the regular breakers they replace. The use of AFCI receptacles has come down in price in recent years due to the volume of products being sold. You can now find AFCI receptacles in the $40.00 – $30.00 CND range at local home improvement stores in Ontario. Although this is just my opinion I think that they will eventually be in line with the GFCI’s that cost around $20.00 CND.
Recent Ontario electrical code changes have led to mass producing various breaker types due to their improved safety features. In the future I anticipate that you will start to see more combination AFCI/GFCI and CAFCI devices in use. The cost of these devices is likely what makes them less common as they can be quite expensive. Currently the trend is to have this technology protecting branch circuits everywhere throughout a home.