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Thread: Dual function circuit breakers

  1. #1

    Dual function circuit breakers

    Please excuse my ignorance about all things electrical but I consider electricity inherently frightening and evil - probably dating to an unfortunate encounter with electrons as an infant... . We live in 1980s house without any known electrical issues but I am aware that new construction requires GFCI and AFCI protection of many circuits. I further understand that there are now dual function breakers offering both forms of coverage. So the question is - any reason not to swap out all the breakers in my house (and workshop) with the newer type? I will of course “hire that out”.
    Thanks in advance,
    Jeff

  2. #2
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  3. #3
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    Check with local codes first. Here some circuits are not permitted to be on an arc fault breaker, such as the smoke alarms.

  4. #4
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    You may also run into issues that will be hard to find, that may not always be a problem, or at least not when it makes any sense. A lot of those houses wired then used shared neutrals, all over the place. Short story: Arc fault, and ground fault breakers don't play well with shared neutrals.

    Personally, if it's not broke, I wouldn't "fix" it, or at least, not by simply changing the breakers.

  5. #5
    Quote Originally Posted by Tom M King View Post
    You may also run into issues that will be hard to find, that may not always be a problem, or at least not when it makes any sense. A lot of those houses wired then used shared neutrals, all over the place. Short story: Arc fault, and ground fault breakers don't play well with shared neutrals.

    Personally, if it's not broke, I wouldn't "fix" it, or at least, not by simply changing the breakers.
    I agree with Tom. All the new breakers have issues with this and that and can be troublesome. Plus they are much more expensive than a standard breaker. I'd just let it be myself.

    I agree with Tom. All the new breakers have issues with this and that and can be troublesome. Plus they are much more expensive than a standard breaker. I'd just let it be myself.

  6. #6
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    If it makes you feel safer or helps you sleep better, go for it, but there are tradeoffs, some of which have been mentioned above.

    If you have multiwire branch circuits (shared neutral circuits) you will have (or should have) a breaker box full of two pole breakers or at least pairs of single pole breakers with the handles tied. These can be replaced with two pole combination breakers.

    Depending on the brand of your panel, combination breakers may not even be available.

    The main issue (besides cost) with AFCI breakers and Combination (AFCI and GFI) breakers has been and still is false trips on certain kinds of loads. Unfortunately, those loads tend to be things like motors, especially brushed motors, which is not optimal for power tool woodworkers. They have gotten a lot better in this regard since they were first introduced, but false tripping remains a problem. Some brands are better than others. For example, when I redid my basement and workshop a couple of years ago, I put combo breakers on all the new circuits, which happened to be spread across two different subpanels, one Square D and the other Siemens. I had frequent false tripping on the Siemens breakers to the point that I replaced several of the combo breakers with GFI only breakers. The Square D breakers have rarely false-tripped.

    The combo breakers are bigger than standard breakers. They still snap into the same slots, but they extends further into the part of the panel where all the wires are run. A lot of older panels were narrower and are so jammed full with wires that the extra room required for the combo breakers just isn't available. This is aggravated by the fact that GFI or Combo breakers have a neutral wire attached to the breaker that has to be run to the neutral bar, and these extra wires just compound the lack of space in older panels.

    Your electrician will be familiar with all these issues and can advise you whether or not you can easily convert. In any case, I'd suggest avoiding AFCI or Combo breakers on workshop circuits due to the false trip issue.

  7. #7
    Quote Originally Posted by Jeff Clode View Post
    Please excuse my ignorance about all things electrical but I consider electricity inherently frightening and evil - probably dating to an unfortunate encounter with electrons as an infant... . We live in 1980s house without any known electrical issues but I am aware that new construction requires GFCI and AFCI protection of many circuits. I further understand that there are now dual function breakers offering both forms of coverage. So the question is - any reason not to swap out all the breakers in my house (and workshop) with the newer type? I will of course “hire that out”.
    Thanks in advance,
    Jeff
    Sometimes the GFCI and AFCI breakers don't do well with electric motors, especially something like an air compressor that draws a lot at startup. It won't hurt anything except perhaps many trips to the breaker box to reset a breaker.

  8. #8
    Thank you all - exactly type of info I was looking for.
    jeff

  9. #9
    At this time, AFCI's are not required in shops, but GFCIs are.

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    The box used in your 1980's house may not accept the breakers that are currently available and you may need to change the box. It also may have been wired with two circuits to each breaker., which doesn't work well with GFCI or AFCI breakers. Our new Panasonic inverter microwave came with instructions to not use it on an AFCI circut.
    Last edited by Lee Schierer; 11-29-2019 at 7:39 AM.
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  11. #11
    When I was doing construction, the electricians complained if they stapled the wires as required by the inspector, then the ground fault would be set off. We had all sorts of problems with temporary power after the code required them to be ground fault. My 80's house has only ground fault in the bathrooms.

  12. #12
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    Check code it used to be the refrigerator and washing machine could not be on GFCI. I think the dryer could be GFCI. No idea, but I doubt if arc fault is allowed for the fridge.
    Bill D

  13. #13
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    I am not sure if you have priced the breakers out but many brands run 40 to 50 dollars. A previous code only required AFCI breakers in the bedrooms (fire protection) and GFCI in areas that could be potentially wet . . . garage, kitchen, bath, exterior, etc. So if cost is an issue possibly doing a partial update may be a acceptable compromise.

  14. #14
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    Unless you are touching something grounded like a faucet a GFCI is not going to do anything. If you are in the middle of a building with a dry floor touching a 120 volt wire should do nothign but give you a tingle. Especially if you are wearing dry socks or dry shoes.
    Bill D

  15. #15
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    True Bill, but near every hot wire is a neutral and a ground, and if you managed to touch the hot wire, not hard to imagine you could also touch one of the others.
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