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Thread: If a 30a breaker eventually trips, how much extra would 40a go?

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    If a 30a breaker eventually trips, how much extra would 40a go?

    If a 30a breaker trips eventually while welding - how much extra would a 40a, an extra 10a rating, get?

    If the breaker trips immediately it would obviously be too weak. Whereas after running a bead for a while that would suggest the current is just tickling the upper limit. In that case, my theory says 10 more amps would curb the trips pretty easy.

    In practice, does that work? Who's run in to this that might be able to shed some light on it?

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Quote Originally Posted by FlyFishn View Post
    If a 30a breaker trips eventually while welding - how much extra would a 40a, an extra 10a rating, get?

    If the breaker trips immediately it would obviously be too weak. Whereas after running a bead for a while that would suggest the current is just tickling the upper limit. In that case, my theory says 10 more amps would curb the trips pretty easy.

    In practice, does that work? Who's run in to this that might be able to shed some light on it?
    What you say is true but you need to have wire rated for 40 amps otherwise you have made it possible for the wire to overheat and could start a fire. I know for welder circuits they take into account for the duty cycle and sometimes use smaller wire than if it were a steady amp draw . Personally I would use 8 gauge wire on a circuit for 40 amps.

    The other question is what welder setting is your 30 amp breaker tripping? If you are not maxed out then you might need more than a 40 amp circuit. The back of your welder should give full load amps and surge amps. I would design the electrical circuit for full load amps. Most breakers are delayed and will take the short surge amps rating .

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Is the welder 115 volts or 230 volts?

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Is it a 30 amp dedicated circuit just for a welding machine or does it have other loads? Welding circuits are treated differently under the NEC, and sometimes could have oversized circuit protection that is perfectly safe. BTW #10 wire will never overheat and cause a fire on a 40 amp breaker.

    PS Before you decide anything, with the power off, pop the cover off to the panel and check the lug connections to the wire and make sure they are good and tight. Loose connections = heat = circuit breaker trip.
    Last edited by wmgeorge; 08-06-2020 at 03:44 PM.
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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    I would use a 50amp 240volt circuit.
    Most stick and TIG will work.

    MIG welders you need to read what size welder you using. A light MIG can a 20amp and very large MIG may need up to 200 amp.

    Dave

    Quote Originally Posted by FlyFishn View Post
    If a 30a breaker trips eventually while welding - how much extra would a 40a, an extra 10a rating, get?

    If the breaker trips immediately it would obviously be too weak. Whereas after running a bead for a while that would suggest the current is just tickling the upper limit. In that case, my theory says 10 more amps would curb the trips pretty easy.

    In practice, does that work? Who's run in to this that might be able to shed some light on it?
    Last edited by smithdoor; 08-06-2020 at 09:50 PM.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    240 volt machine, dedicated circuit. Edit - one 120/240v outlet, nothing else between the outlet and the breaker. So it is used for multiple things, but never simultaneously.

    I am thinking ahead here. I have not popped the breaker yet. The circuit feeds in to a garage and I have run 120v loads off it - welder and air compressor, namely. The 240v machine is an old Idealarc 250, round top. I fired it up with a 1/8" 6011 and 110 amps or so - no trouble at all. However, I haven't run a long bead with it, either.

    I am planning to run some heavier rods. The machine is going through a restoration at the moment so I can't fire it up right now. I am hoping next week. Wednesday I get a paint order in, supposedly. I am hoping to have the machine ready to reassemble by then - if not already together. I can run a few higher amperage settings and cook come rods just to see what happens. I'm sure that will give me a better idea of what the "cut off" point is on welding amperage to circuit breaker popping. The machine supposedly will do 300a on AC. I don't see getting up that high, but I could be in to the 200's.

    You can check out the thread I have in the Lincoln forum for details on the machine/project.
    https://weldingweb.com/vbb/showthrea...p-Idealarc-250
    Last edited by FlyFishn; 08-06-2020 at 11:47 PM.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    I've seen sub 10 dollar AC clamp amp meters on the internet delivered

    Get one and see what your machine draws when welding at different settings - that will give you a decent idea of what's going on.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Look at the I1eff rating of your welder. That is a calculated figure that is based on duty cycle that you can use as a guide to size the conductors. If your I1eff is ~30A, then the conductors are allowed to be 10 gauge, even if your I1max is higher than 30A. If the I1eff is more than 30A, then you need 8 gauge.
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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Quote Originally Posted by FlyFishn View Post
    240 volt machine, dedicated circuit. Edit - one 120/240v outlet, nothing else between the outlet and the breaker. So it is used for multiple things, but never simultaneously.
    The welder duty cycle rules are not applicable to a outlet you will run other things on. The duty cycle thing was written for industrial welders that are run hundreds of feet to feed them. It was for cost savings on the feeds with large wire and long lengths.

    In the general residential/commercial setting it is best to run all circuits with the proper size wire for the breaker. We are not talking huge savings to install less than the best feed you can give it.

    Best to run a 50 amp circuit with #6's and rest assured you are good then. Always useful for most whatever welder/plazma cutter you want in it and function with enough power to work like it should.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Don't those old Idealarcs require something on the order of a 60-75amp circuit? Newer ones require about the same input.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Quote Originally Posted by farmersammm View Post
    Don't those old Idealarcs require something on the order of a 60-75amp circuit? Newer ones require about the same input.
    Oh crap I missed that part. A big ole' 300 amp transformer machine. Yea that is gonna need a real circuit(if you wanna use any of the high end), disconnect and wired with a decent length of SJ

    I guess if he was running on 30 then 50 would be better but not the circuit that needs.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Or, the breaker itself is weak/going bad, , , ,
    What is the sound of one knee jerking?

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Quote Originally Posted by FlyFishn View Post
    I am thinking ahead here. I have not popped the breaker yet. The circuit feeds in to a garage and I have run 120v loads off it - welder and air compressor, namely. The 240v machine is an old Idealarc 250, round top. I fired it up with a 1/8" 6011 and 110 amps or so - no trouble at all. However, I haven't run a long bead with it, either.
    It shouldn't matter how long the bead is. If the breaker doesn't trip at a given welder setting, assuming your wiring is up to the NEC, you should be able to weld as long as you like (or at least until the welder reaches its duty cycle) without tripping the breaker. You could weld all day long continuously with the same welder setting, and the amperage draw should not increase. It's not cumulative, like kWh used...

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Quote Originally Posted by Kelvin View Post
    It shouldn't matter how long the bead is. If the breaker doesn't trip at a given welder setting, assuming your wiring is up to the NEC, you should be able to weld as long as you like (or at least until the welder reaches its duty cycle) without tripping the breaker. You could weld all day long continuously with the same welder setting, and the amperage draw should not increase. It's not cumulative, like kWh used...
    You are correct on the amperage draw not increasing and the accumulation not being akin to kilowatt-hours. However, heat build-up at a breaker can cause it to pop. And drawing a lot of current through it can cause it to heat up.

    Quote Originally Posted by thegary View Post
    Most breakers are delayed and will take the short surge amps rating .
    That is the question - if I can run 2x 5/32" 6011's at 145 amps weld current and the breaker pops on the third rod would the extra 10 amps going from a 30a to a 40a breaker get me to keep up with the duty cycle of stopping to change rods for, say, 5-6 rods in a row?

    Once I get my machine back together I will be really curious to put some real numbers to this question...

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    My old Idealarc 250 lists the input current at 230 V, 70 Amps welding at 200 Amps, 30 Volts and 50% duty cycle.
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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    So far I have made it about 4" with a 5/32" 6011 and 175 amps before the breaker went. Yeah, that was too hot for the rod, but I was just burning at that amperage to see what would happen. My result = circuit breaker blew. I suppose that makes sense if 200 welding amps is 70 amps input. 175 welding amps isn't going to be less than 1/2 of the input amps at only 25 less welding amps. Though, I am surprised I even got a 4" bead.

    I burned a whole 1/8" 6011 at about 115-120 amps without the breaker going. I will try a few rods back-to-back when I get a chance and see what happens. I also have an amp meter I can put inline on the welder power supply (240v side) that will show, hopefully, a better representation of what the current draw is through the line (I am not sure what the reaction time is of the meter response, so I am not sure if it is going to be a real accurate reading or not).

    If I can run 1/8" rods at 90-120 amps that is going to cover 98-99% of what I weld, and envision welding in the future.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Should have just gone with an inverter welder, IMO.
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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Quote Originally Posted by Oscar View Post
    Should have just gone with an inverter welder, IMO.

    At some point I will. When that time comes the Idealarc will still be around as a backup. That is a fantastic plan for me.

    For what it is worth, the question in this thread was on how much more welding time I could get on 10 more amps of breaker rating if 30 amps isn't enough = as in if a 30 amp breaker eventually goes the longer it takes to pop the closer the load is to the rated load (in contrast - the faster it pops the further above the rated load). That is independent of welder - that only depends on the load on the circuit. So if you draw 40 amps from an inverter welder pushing 200 welding amps or 40 amps from a transformer welder pushing 110 amps the draw is still the same 40 amps. That is the value I was questioning.

    Also for what it is worth, I measured the supply current under load and at around 115 amps welding current (setting on the machine, I am not sure what the measured welding current is = have not measured it) I am drawing 36-44 amps supply on a bead, without the breaker popping.

    I have not done back-to-back rods yet. There has been a good amount of cool down time between beads.

    I made a video of the parameters under load. This goes along with the details in my restoration thread on figuring out the voltages now. However, the information goes right in line with the subject of the thread here.


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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Why is it so difficult to put in a bigger breaker like a 60 amp? I would guess the house circuit is 100 amps minimum. You're limiting what your machine is capable of and once you get more experience you might want to burn bigger rods than 1/8". Why overwork the breakers and risk getting the wiring hot.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Quote Originally Posted by Welder Dave View Post
    You're limiting what your machine is capable of and once you get more experience you might want to burn bigger rods than 1/8". Why overwork the breakers and risk getting the wiring hot.
    I agree. I am finding that there is a difference between what I would like to do/have and what reality shows is possible. The line between what is possible and not (breaker popping) hasn't been clearly defined yet, but I am figuring it out. Running another permanent circuit isn't possible.

    Where that line is drawn will play in to future projects.

    One future project is a set of heavy gauge lead-in cables for generators (not for one unit or one location, basically big extension cords for any temporary set up). That same cable set up could be used as temporary wiring for getting a higher amperage supply to the welder. In that case, provided the gauge cable is adequate for the run and the load, I could match anything I wanted. 6/4 SO might be about as big as I would consider. There is 4/4 also, but long runs get expensive really fast and I would need 125-150 feet.

    However, I want to find what the max is that I can do on the circuit I have.

    I can tell for certain that I can weld much much heavier on a 30a circuit with the Idealarc than I could ever do with my flux core machine so I've already won the weld power battle. There isn't a whole lot I'll ever weld that is more than 1/2" thick steel. The vast majority would be 1/4" or less and that 3/16"-1/4" range is what has always been too much for the flux core machine but I've used it because that's what I had.

    For one project I have in mind I would like to be able to run some thicker rods (1/4" even) so as to put down more fillet metal in 1 pass, but the reality I see is there isn't any way I can touch a 1/4" rod right now. I haven't blown the breaker on a 1/8" 6011. I did break the breaker on a 5/32" 6011, but I intentionally ran it over amperage at 175a just to see what would happen. I'd like to see what the supply amperage is with the 5/32" rod run within spec. I'm sure it will be more than the 44a I saw with the 1/8" - but how much I am not sure - and where/at what point the breaker will go I am not sure.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Instead of saying you can't, give a reason why. Surely you can't have only a 30 amp house circuit. When I lived on an acreage an electrician friend hooked up a welder plug to the main 100 amp breaker/fuse (on the pole outside) because there was no room for another circuit on the breaker box inside. He said it doesn't hurt to have a bigger breaker and it's going to trip if something goes bad with the welder.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Quote Originally Posted by Welder Dave View Post
    Instead of saying you can't, give a reason why.
    The reason doesn't matter to the Internet Gods, that's why you're not getting a reason.

    I find it interesting that no one has come to the table with an answer to the technical question of how much further the extra 10 amps on a breaker would go. Rather, they change the question/answer entirely to a new circuit.

    Quote Originally Posted by Welder Dave View Post
    Surely you can't have only a 30 amp house circuit. When I lived on an acreage an electrician friend hooked up a welder plug to the main 100 amp breaker/fuse (on the pole outside) because there was no room for another circuit on the breaker box inside. He said it doesn't hurt to have a bigger breaker and it's going to trip if something goes bad with the welder.
    You are correct. That is why I am throwing the option of the below in:

    Quote Originally Posted by FlyFishn View Post
    One future project is a set of heavy gauge lead-in cables for generators (not for one unit or one location, basically big extension cords for any temporary set up). That same cable set up could be used as temporary wiring for getting a higher amperage supply to the welder. In that case, provided the gauge cable is adequate for the run and the load, I could match anything I wanted. 6/4 SO might be about as big as I would consider. There is 4/4 also, but long runs get expensive really fast and I would need 125-150 feet.
    Why does that work and not a permanent install? Because I can snake the cable where I need it without "running the cable". Just like an extension cord. None of this is "permanent" - the welders, drill press, any of my other tools, etc. They all run off extension cords when I need them or where I need them. Until the big welder I didn't have much need for more than a dedicated 15a/120v for my compressor (or 20a with other stuff). With 1 machine I've nearly tripled the amperage requirement and doubled the voltage requirement.

    Again, why I won't put a permanent circuit in doesn't matter. Everything I do and run is temporary anyway. If I move to a heavy breaker and the 6/4 SO, lets say, that is going to be around $600 worth of SO cable alone. Again, I do have a lot of other purposes/ideas for that so it isn't "spending $600 to run a $100 welder" - but that is an investment that will have to wait.
    https://www.amazon.com/Cable-Portable-Power-Gauge-Conductor/dp/B071P1XBWK/ref=sr_1_7?dchild=1&keywords=6%2F4+so+200+feet&qid =1598370241&sr=8-7


    If I go to 4/4 SO that adds another $400 for the same length.
    https://www.amazon.com/Cable-Portabl...8370241&sr=8-7

    I'll run the numbers later if I have to on current vs gauge etc.
    Last edited by FlyFishn; 08-25-2020 at 11:51 AM.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Champagne dreams on a beer budget. In hindsight you should have bought a 160 amp import inverter. Interesting as I was just reading on another forum where a guy bought a new track skid steer and mini excavator. He suggested his friend buy a tandem dump truck and trailer to haul his machines for him. Wasn't really thought out too well.

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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    in a perfect electrical world:

    30x240 = 7,200 watts you can run through a 30amp circuit

    40x240 = 9,600 watts you can run through a 40amp circuit.

    You get an extra 2400 watts of power available.


    But since everything isn't exactly perfect, it is rather difficult to figure out exactly* how much extra welding can be done with that extra 10amps.

    * type of machine, age of CB, Voltage drop etc.
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    Re: If a 30a breaker eventually trips, how much extra would 40a go?

    Quote Originally Posted by Broccoli1 View Post
    in a perfect electrical world:

    30x240 = 7,200 watts you can run through a 30amp circuit

    40x240 = 9,600 watts you can run through a 40amp circuit.

    You get an extra 2400 watts of power available.


    But since everything isn't exactly perfect, it is rather difficult to figure out exactly* how much extra welding can be done with that extra 10amps.

    * type of machine, age of CB, Voltage drop etc.
    Quote Originally Posted by FlyFishn View Post
    ...I am drawing 36-44 amps supply on a bead, without the breaker popping.
    The line voltage under load at the machine is 238v. So if you take the high amperage of 44 amps that would be (238 x 44) = 10,472 watts (at the machine, not the breaker = not including line loss under load). That's pulled through a 30 amp breaker without breaking.

    Thanks for the thoughts on the wattage vs breakers - that is the closest to what I was originally asking that anyone has come up with. I suppose I will test it further and see what happens.

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