In this episode I go over the response I got back from the Eaton engineers about AFCI, GFCI, and DF (AFGF) breakers. I have to say, I'm impressed with the prompt response and depth of detailed information they provided.
Many of you who follow us on Facebook, and are engaged in the several groups we're a part of, participated in the roundup for questions to ask the Thank you for all of the input, we got a fairly quick response from them, and they did not short us on the details.
I'd like to extend a huge thank you to Lanson D Relyea - Product Line Manager, and Robert (Bob) E Handick - Master Electrician at Eaton for taking the time to answer these questions with great detail and promptly.
1)Will they come out with a duel function type CL Classified breakers? They have them in AFCI (Eaton cl120caf).
[Eaton]: Eaton may consider releasing a classified version of AFGF if there is enough demand. The testing requirements for classified breakers per UL are very labor intensive and expensive. Eaton has to test the breaker in every family of loadcenter across all manufacturers to verify the breaker and loadcenter will work together as a system.
2)Why do all brands twist the neutral pigtail, and is there any down-side to straighten them or to cut them short?
[Eaton]: The twisted or coiled pigtail is simply to fit the breakers in the packaging in the most efficient way. When installing the breakers the pigtail can be kept coiled to allow the ability to extend it or keep short without the need to custom fit via cutting and re-skinning. There is no harm caused by cutting the pigtail or to extend using a wire nut and extra piece of wire (as allowed by the local AHJ).
3)Is there any new developments being made for motors? They need to have more tolerance built into the AFCI's for motor circuits... Nusicance tripping on refrigerator, freezer and window A/C units gets old real fast. May be different rated AFCI'S, like the personnel and equipment GFCI'S
[Eaton]: Current generation Eaton AFCI product has been designed to be the least susceptible to brush type universal motors that are inherently noisy due to the nature of their design. Our current product does a really good job at distinguishing the difference between the intended arcing inside the motor verses a dangerous unintended arcing situation. Eaton has a dedicated team of engineers that constantly looks to refine our algorithms to ensure compatibility with new and existing appliances.
4) I've noticed a lot of problems with mixed loads. Led and fluorescent on the same circuit. I've had a lot of problems with the tripping when led lights are on same circuit as an incandescent light and especially with a ceiling fan. What gives?
[Eaton]: We believe the real issue is the conducted emissions (noise) being generated by the LED’s electronic switching power supply more so than mixed loads. Some LED’s are found to be exceeding the conducted emissions limits set by the FCC. This noise looks very similar to a series arcing condition and if all conditions are met, the breaker may trip. The breaker also need to have a minimum amperage of current flowing through it at the same time it recognizes the noise in order for its arc protection to kick in (varies by manufacturer) which is probably why you see more issues when using other loads along with the LED’s on the same circuit. LED does not draw much current so the noise itself does not trip the breaker until you add more load such as the incandescent bulb as you described.
5)Please ask about the coordination with appliance manufactures. The breaker needs to know the signature of appliances that create arc like noise and know to ignore them. Some manufactures ignore the need to make things that comply or to inform breaker manufactures. We end up with the requirement for arc detecting breakers but manufactures that make things that will cause trips which are not arcs. We need better coordination. How do they address this, and do they even try?
[Eaton]: Eaton designs our AFCI devices expecting that appliance manufactures will to adhere to the FCC regulation for conducted emissions. If there is a new appliance or device on the market that exceeds FCC limits, it may create an issue for interoperability.
NEMA has designated a task force to align the AFCI manufacturers with the appliance manufacturers through AHAM (Association of Home Appliance Manufacturers). This partnership is designed to set common design standards across both manufacturing groups. It also allows for a direct connection between manufacturers if there if there are any interoperability issues between the specific brands.
6)Why do some power tools(shop vacs especially) trip afci's. I know a lot of power tools have brushes which arc, but aren't the new combination afcis supposed to be smart enough to prevent tripping?
[Eaton]: These power tools, shop vacs and vacuum cleaners use brush type universal motors which are inherently noisy due to the nature of their design. This noise looks almost identical to dangerous arcing condition and sometimes would cause unwanted tripping in legacy AFCI devices. These devices can also have high inrush currents which can also be similar to an arcing event. The AFCI industry has continued to evolve its technology to get better at distinguishing the difference between the arcing inside the motor verses a dangerous unintended arcing situation.
7)I've had an issue with AFCI breakers and AFCI receptacles on the same circuit. They seem to chatter and trip each other, or if you have any ballasted lights (LED especially) they make the lights go haywire like a 70's dance party! Also, I've seen the same with GFCI receptacles installed on the same circuit as a GFCI breaker. One keeps tripping the other, only way to fix it in both circumstances is to remove one or the other. What's going on inside these things to make this happen?
[Eaton]: We have not identified any broad issues with having redundant protection whether it by AFCI or GFCI on the same circuit. We have witnessed LED lights flickering as you mention but that typically occurs when the lighting control device is not compatible with the low voltage transformer or power supply and is not an issue with the AFCI device. It is essential that the dimmer is designated compatible for the type of light being powered as well as the power consumption of the circuit.
8)What are the characteristics of arcing? I keep seeing that term (AFCI devices detect "characteristics of arcing and open the circuit...) but nobody seems to know what that means. Is it a sudden change in frequency, waveform shape, resistance, etc...what's happening to the circuit during an arc (voltage, current, resistance, frequency) etc that make the breakers sense something wrong?
[Eaton]: There are two kinds of arcing, high current or “parallel” arcing and low current or “series” arc. Parallel arcing is a occurs between two parallel conductors and has the two characteristics or a large current flow and no lag or lead of current relative to voltage. Current lags voltage for inductive loads and current leads voltage for capacitive loads. Series arcing is a little more involved. It includes a circuit that has a gap in one conductor (line or neutral) followed by a load wired in series. At the beginning of a half cycle, when the voltage difference between line and neutral is small, no arcing occurs and no current flows. When the voltage potential across the gap becomes large enough during the half cycle, an arc is generated and current flows. As the half cycle nears its end, the voltage potential drops and the arc stops. The high frequency noise generate by an arc is broadband, whereas the spectrum of HF noise generated by a non-arcing load is not uniform and has peaks and nulls depending on the load. AFCI breakers look for these characteristics to detect an arc and safely trip.
9)What are the most common issues you find or have complaints about with your AFCI vs GFCI breakers? Sometimes when retrofitting a house with recessed lighting, I'll add a dimmer and get nothing but problems from arc faults.
[Eaton]: It is essential that the dimmer is rated for the type of light being powered. Also need to verify that the LED (or other lighting source) has a FCC, part 15, class B rating for consumer use. Class A devices are for commercial use and usually do not have high frequency filtering built in which can cause interaction issues.
10)(another member) We've recently been talking about something very similar. Ran a dedicated circuit for a fireplace igniter because we were worried about the arc faults acting up on us. Technically this should be on an AFCI but it won't hold when the igniter arc's.
[Eaton]: Eaton has not identified any issues with igniters. Typically the arc does not sustain long enough or have enough current flowing for our series arc detection to trip.
11)Why can't you combine neutrals on two different circuits without the AFCI tripping. They have to be on their own circuit to work. Is it that the added length of the combined neutral conductors changes the overall resistance/voltage drop or is it sensing the difference in phase angles (jumping from 60hz to 120hz suddenly)?
[Eaton]: The reason for this is that some AFCI devices on the market have built in ground fault protection. Therefore, you cannot share neutrals from two circuits. The breaker monitors the current flowing out on the black (hot) and the current flowing back in on the white (neutral) conductor. If 5 amps leaves the breaker, 5 amps needs to return. If there are two neutrals tied together on the load side of the breaker, the return current is split in half coming back and the breaker will trip every time. It is also suggested not to combine neutrals because it can make troubleshooting more difficult. If there is an issue and the breaker trips, you must investigate all the branch circuits tied together.
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photo courtesy of www.eaton.com