Arcsafe subreaker work with a welder?

Discussion in 'General foundry chat' started by Zapins, Jun 22, 2018.

  1. Zapins

    Zapins Gold

    The electrician went for a permit at the local town counsel. The counsel said the sub breaker needs to be an arc-fault circuit interrupter (AFCI) breaker and won't negotiate even though its for the garage.

    Will an arcsafe breaker stop the arc from a tig/mig/arc welder? Will my welders work? I can't find info online about it clearly stated.

    Also irritating the price jumps up from 500 to 850 + I need to buy a more expensive arcsafe breaker just because it's an arc fault.
     
    Last edited: Jun 23, 2018
  2. PatJ

    PatJ Silver

    I can't find an AFCI breaker larger than 20 amps.
    Do they actually make an AFCI breaker large enough for a welder?

    Its very easy to wire up a welder.
    Cost is perhaps $200.00 max. (when doing it yourself), but probably less.

    Ask for a cut sheet on the breaker, and post it here.
     
  3. DavidF

    DavidF Administrator Staff Member Banner Member

    whats the difference on a afci vs gfi breaker?? Think Id skip the permit and just wire it in myself....
     
    Jason likes this.
  4. DavidF

    DavidF Administrator Staff Member Banner Member

  5. FishbonzWV

    FishbonzWV Silver Banner Member

    AFCI breakers are used on each individual circuit, not to feed a subpanel.
    I'm assuming you are installing a 100 Amp panel and your breaker in the main panel will be that.
    They don't make 100 Amp AFCI's.
    The way around the cost is to have the contractor install the subpanel, wire in one 20 Amp AFCI outlet, call the inspector. It should pass the inspection. Now you're good to install all the outlets you want without further ado. Just tell your contractor to come back after the inspection and finish wiring the circuits if you're not comfortable doing it.
     
  6. You do need to follow the code after you have requested a permit.

    Your contractor also needs to know the code. Fishbonz has it right, the council is requiring an AFCI breaker so install one. My understanding is AFCI is only single phase, 15 or 20 amp to protect 120 volt or 240 volt single phase outlets. Your installation of a 40 amp or 50 amp two phase breaker wired to a welder should not fall under the code use for AFCI, neither are those breakers available. So you follow the council and assume they understand the code which does not apply to the two phase breaker but they require AFCI for your single phase 120 volt breakers.

    Your contractor needs to know the code and make the installation that meets council requirements and the code. It should not have an effect on your welder.
     
  7. FishbonzWV

    FishbonzWV Silver Banner Member

    Your installation of a 40 amp or 50 amp two phase breaker
    Just for clarification, those are 2 pole breakers, not 2 phase.
    Houses are single phase unless you are paying high dollar for a 3 phase drop, which is not the norm. Even then, with 3 phase, you can't run off 2 out of the 3 phases.
     
  8. FishbonzWV

    FishbonzWV Silver Banner Member

    whats the difference on a afci vs gfi breaker??
    Basically
    A GFCI monitors a short between the hot and ground.
    An AFCI monitors a short between the hot and neutral.

    GFCI's are required on any outdoor outlet or within 6 feet of any water source indoors.
     
    Jason likes this.
  9. Got me! Laymen often refer to 240 in the US as two phase because it involves both legs of the feed to the house, which are 180 degrees out of phase, rather than 120 which is only one phase and neutral. from what I understand AFCI is only for one phase to neutral. Is that incorrect?
     
  10. Jason

    Jason Gold

    When it comes to the city, It's better to ask for forgiveness than permission. Now you have some dumbass trying to require you to install something that they have ZERO knowledge.
    Even worse, Now they know you exist so finish whatever it takes to get the a-hole to sign the paper.

    We have a saying in the flying world. Those who can, do. Those who can't, teach. Those who can't teach, evaluate! (Freight dogs, flight instructors, Feds) see?
    This is the norm with permit departments. Do you think your local guy even knows what a TIG welder is? I doubt it. He's quoting arbitrary shit he read someplace with no practical knowledge.

    I can change out someones entire AC system in their home without a permit; legally. But I had some guy rip his own stuff out while doing stuff on the house. You guessed it. The city was there for another permit and asked about the AC. NOW a permit suddenly becomes required for the NEW INSTALL of the AC. The homeowner tried to save a few pennies and it cost him THOUSANDS because I could no longer replace his AC for him. Then, he had the balls to ask me to get his equipment at cost? Funny thing, I don't even charge for removal. I charge dead nuts my cost of the equipment plus 1200bucks for labor. Nice chunk of cash for 1 day worth of work. I do good, and they save a few grand.

    My new TIG machine doesn't even require a neutral so an AFCI wouldn't even be required!
    See what I mean? Your local guy is truly an asshat!
     
  11. FishbonzWV

    FishbonzWV Silver Banner Member

    I understand AFCI is only for one phase to neutral
    They do have 2 pole AFCI's but the only time you would use it is if you have a 4 wire piece of equipment.
    True 240v and 3 phase equipment does not require a neutral, only a safety ground. If that equipment has power supplies in it, then they need a neutral. In 240v machines, if they tap one of the legs for 120v use then it also needs a neutral, that's where the 4 wire hookup comes from.

    I deal with electrical inspectors quite often and believe me, the less they have to inspect the better off you are. That's the recommendation to Zap. If his contractor is proficient, there's nothing to worry about as far as being safe. You just get by the red tape easily.

    Here's an example:
    I have some RV hookup boxes, 30Amp 3 wire and 50Amp 4 wire circuits including the breakers.
    I had 50 Amp breakers and 6 gauge wire on hand to feed the box. Can I get past the inspector, no. The total amperage of the box is 80.
    Can I put two RV's on the same lot, no.
    What did I do? Put a cover plate over the 30Amp outlet and disconnected the 30 breaker.
    Pass!
     
    Last edited: Jun 23, 2018
  12. PatJ

    PatJ Silver

    A few minor clarifications:

    Generally in the US, residential areas are fed from a single medium voltage overhead power line (for economy), and houses are fed from a center-tapped single-phase transformer, which provides both 240 volts (line-to-line), and 120 volts (either line to neutral). So you have two "lines" (L1 and L2), and you have single-phase because it is all fed from a single-phase pole-mounted transformer.

    If you get a true 3-phase service installed at your house, it means they have all three medium voltage conductors on the pole line, and they install three single-phase transformers on the pole to provide you with three phase, generally either 480Y/277 volt or 208Y/120 volt. In either case you have three phase conductors plus a neutral run to your house, and yes you have true three-phase and can use all three phases.

    Some three-phase rural services use two transformers in an open-delta configuration, and that produces 3-phase using three phase conductors but no neutral, and this arrangement is generally for a remote pump in a rural area, and is not a very good 3-phase service (I would not use this type of arrangement).

    A GFCI receptacle measures the current flowing in both the energized conductor (in the US residential typically the black conductor) and also measures the current in the neutral conductor.
    If the two currents do not equal each other, then that means there is a ground fault in the system, ie; current is flowing out the energized (black) conductor and instead of returning via the white neutral wire, it is returning via a path such as through a human via some conducting part such as the metal frame of an appliance.
    Above 10 milliamps, current flowing through the human heart starts heart fibrillation, which prevents it from pumping blood, and this can generally only be corrected ironically by applying a massive voltage to the heart to cause a hard contraction, after which it generally begins to beats regularly again.
    So human-rated GFCI receptacles trips the circuit off if it detects line to ground current above 10 milliamps. (the standard may have changed to 5 mA, but you get the idea).
    And there are also GFCI circuit breakers that are not rated for protection of humans, but rather are designed to prevent equipment damage, and so they trip at much higher than 10 milliamps.

    An arc fault breaker apparently (check me no this) is reading the waveform, and looking for abnormal fluctuations.
    A little internet research indicates that arc-fault breakers are prone to nuisance tripping, and while the theory of their operation for safety is good, in actual use they really don't perform well because there are so many electrical devices that produce a lot of electrical noise when operating normally, such as electronic lighting ballasts, and the arc flash breaker cannot tell the difference from normal electrical noise and an actual fault on the circuit.

    It is the low-level faults that burn up electrical wiring and components.
    Short circuit arcing generally provides a high-impedance path for electrical current to flow through ionized air, so you may have a large and very damaging arcing situation in an electrical system, the current flow may be well below the rating of the protective circuit breaker, and thus the breaker will not trip.
    These arcing flaults often travel along the length of electrical bussing and can cause tremendous damage before they finally develop into a large enough fault to trip a breaker. The carbon that the arc produces settles on the bus insulators, and it must be completely cleaned off to prevent "tracking" or conduction of electrical current, which will can cause another fault.

    Below is an example of a low-current arcing fault (5KV) that failed to open the upstream circuit breaker. The fault began in a single starter, and propagated 20 feet down the bussing in the gear. The moral of the story is replace your switchgear before it replaces itself. 40 year old switchgear is not reliable or safe.

    rIMG_0749.jpg

    r-NO-02-STARTER-IMG_0713.jpg

    r-NO-03-STARTER-IMG_0730.jpg
     
    Last edited: Jun 23, 2018
    Jason likes this.
  13. Petee716

    Petee716 Gold Banner Member

    Thanks for taking the time to write that up Pat. Although I know that all of the topics you touched on get pretty in-depth, your explanations are helpful.
    One thing I'd like to toss in from an experience I had a couple years ago. I put fluorescent fixtures up in my barn prior to running power and having the sub panel installed. When I went to test the lights I plugged an extension cord into the GFCI outlet on my deck and ran it to the barn. When I plugged it in it tripped the GFCI immediately. Turns out that the electronic ballast is not compatible with GFCI.
    I guess one time when that could be an issue is if someone is trying to install a fluorescent light in their bathroom or wet area by tapping off a circuit that has a GFCI in the breaker panel.

    Pete
     
  14. Jason

    Jason Gold

    Crispy critter... I like carnage when someone else is paying the bill. I can smell that sucker from here!
     
  15. Old school AC transformer welders can often trip modern circuit breakers with their transient short circuits and arcs so there is a slower to respond breaker known as a 'D' curve breaker that is suitable. Most stuff I have seen in the stores is 'C' curve and all my workhop is supplied from 'C' curve combination overload and GCFI breakers. I have seen a particular combination of stick welder and overload breaker that tripped randomly fixed with a D curve.
     
  16. DavidF

    DavidF Administrator Staff Member Banner Member

    Well shit Pat, the switch gear at our plant was installed in 1947. There has been alot of controversy with us as operators resetting it, but management says as long as it looks ok then it should be fine.
    Aint that some crap.
     
  17. _Jason

    _Jason Silver

    Zap,

    Your local permit authority is enforcing current NEC code calling for AFCI on branch circuits. Try it with your welder. If it doesn't work, it's easy enough to swap out the AFCI with a regular breaker.
     
  18. When I fixed up my 1950's lathe, I was going to keep all the porcelain fuses and the Bakelite contactor/heater unit but the old contactor phenolic resin was too crumbly and blew away like spores on the wind: into the bin it went.
     
  19. PatJ

    PatJ Silver

    We are getting a little off-topic, but old switchgear is not safe, and old medium voltage switchgear is very unsafe.
    Medium voltage switchgear (over 600 volts, generally in the 5,15,25,35 KV classes) is known for "tracking" over time, and the tracks (which go from high potential to low potential) are conductive.

    Other problems with old gear are that generally modern electrical power systems have a lot more capacity these days, and can deliver much more current to a fault.
    I have seen old gear try to open a fault, but instead the breaker contacts weld together, and then the whole gear burns/blows up. One instance of this I am aware of caused a $2 mil shutdown.

    Other problems are worn springs, worn and pitted contact surfaces, etc. which cause high resistance connections. The heat generated in a high-resistance connection is I squared R, so if R (resistance) goes way up, the heat also goes way up (sometimes red hot). Many people open up the gear while it is energized and do thermal scans (now days you need a moon suit for that).
    The thermal scans are relatively cheap, and they are an excellent predictor of a failure.
    The new switchgear is often provided with view windows so the interior can be thermally scanned without opening the doors.

    I generally work for plants/facilities that lose 1 mil (+) per day if shutdown, so I do power reliability studies and equipment replacement.
    Pretty much all I do these days is retrofit new switchgear in plants that were built in the 50's, 60's and 70's.
    The photos above were switchgear that I was in the process of designing for replacement, and the gear failed several weeks before I got the design complete.
    You don't really want to be standing in front of it when it goes. That is the risk I take working around the stuff, but you have to go somehow, and the pay is good.

    Anyway, its a good question about the arc flash breaker thing. There seems to be a lot of confusion about those these days, and I am not really up on them, but have heard that they generally don't work well.
     
    Last edited: Jun 24, 2018
  20. Zapins

    Zapins Gold

    I appreciate the time you all took to help me out here. Please bear with me I am still pretty unsure of the best option and how to go about it so I'll reply to each of your posts. Basically it comes down to getting my welders working with more power and making sure that the insurance bastards will still pay if something goes wrong, and that I'm not breaking any laws that could cause me/my family trouble.

    If I understand you right I think you are saying that a regular old subpanel box works with a regular old 100 amp breaker. Then from there I'd need to buy an AFCI breaker for each line coming out of the panel?

    I don't have any personal worry over the safety of using a non-AFCI protected plug, but what I worry about is if there is a fire down the road and the insurance company checks the permit and what has actually been installed I don't want them to be able to point a finger at me for doing something wrong and not pay if the house burns down.

    Would doing what you suggest void the insurance? Or is what you are saying the correct way to do it according to the permit? The amount of information on these things is very limited.

    Hmm interesting. From what I understood I had to have it on all outlets. So basically it is just on the lines going to the 115v? Not to a dryer/stove type plug? I'd be fine with that, but I get the feeling thats not what the electrician was telling me, though he could have been explaining it poorly to me.

    My main concern is that the Arc/Tig/Mig welders work and the compressor/large motors I have and kiln down there. I couldn't find much info on whether there were issues with welders and arc fault circuits. I just worry because an arc welder makes an arc and isn't that what the arc fault stops?

    The electrician is E1 certified whatever that means. He can pull a permit for the 150 amp cable I need to run to the garage. He is also a former welder, but he hasn't tried using welders on arc fault protected circuits so he didn't know what to tell me about them.

    Thanks for writing that up Pat. I think I get how they are supposed to work and that they are probably not a good idea for my welders. So the real concern is how do I legally install them and have insurance protection and get the welders to work? I don't know enough about ducking the red tape and getting something passed then changing it later to feel comfortable doing that without a lot of coaching :)

    Will it still be acceptable to an insurance company that I did that if there is a fire/something crazy/rare goes wrong?
     

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