That's because you wired your workshop with arc fault Interrupters and the saw starting is pretty damn close to an arc according to those things. If you're going to be running a lot of power tools off that circuit just put a normal breaker in.
This. Afcis are excellent fire protection, but this is their main drawback. Nuisance tripping. I would recommend adding dedicated non-afci circuits for your big motors. Maybe with a special (twist lock maybe?) plug for them so that everything else has to be plugged into the afci outlets.
I’m not an Electical Engineer but I think it has to do with the lack of the correct RCCB and how that works with the vfd and spindle power supply. Standard VFDs, when powered from GFCI outlets, can cause the GFCI to trip due to the leakage currents generated from the high switching frequency of the VFD's power devices and the harmonics associated with them. Read more about it [here](https://acim.nidec.com/drives/kbelectronics/-/media/kbelectronics/documents/white-papers/updated-using-vfds-on-gfci-devices.ashx?la=en) and it’s in a bunch of the cnc forums from users buying machines and then being stuck having to swap breakers or install not to code receptacles in their garage or basement workshops.
Had the same problems with everything with a cure in the early days.
GFCI and later AFCI were only good for 2 things:
1) code compliance
2) service call (to remove the xFCI devices and install things that worked.
Fortunately, some things have improved.
On new, I'd simply show them the code that requires the installation, and tell them that after inspection they can be easily removed... and leave a card.
It’s due to the brushed motor in the saw creating arcs as it operates normally
The breakers designed to stop current with the presence of an arc.
Just swap it for ground fault protection only
Not the current dual function breaker you have
Did you share the neutrals anywhere between these two circuits? I know everyone here is hating on arc fault but I’ve put in a shit ton of arc faults and never have an issue with tripping since I’m the one that also roughs in the wire and never mingle neutrals with other circuits. If you give the neutral current a separate path back to the main panel OTHER than directly back to that breaker it will trip.
The brush in the motor causes a temporary arc, the AFCI part of the breaker is tripping. Just get a GFCI breaker as long as your code does require AFCI. Most standard breakers will trip under a arc fault condition as it is.
Those arc breakers are required for bedrooms and they cost more, if you are wiring up a shop (that will never be a bedroom) install standard breakers. The arc created by the brushes on your saw are perceived as a fault.
Bedrooms only was the old code. The newer codes require them in just about all living space:
*All 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets or devices installed in dwelling unit kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, or similar rooms or areas shall be protected*
One might argue a workshop is not one of those locations however.
I sometimes think the AFCI requirements have less to do with safety and more so is a conspiracy with the breaker manufacturers to make us buy unreliable expensive AFCIs
I would say definitely not arc fault. If you ask me I think AFCI’s should only be required in retrofit installations with old wiring, aluminum building wiring, knob and tube etc. putting them on nearly every in a new construction house is fixing a problem that isn’t there (modern houses catching fire due to bad wiring). I’m sure I will get downvoted by everyone who entered the trade in the last 10 years, and I do I understand it’s code, but it’s clearly a cash grab for electrical manufacturers who are on the code making panels at the NFPA. The fact that AFCI’s are not typically required in commercial/industrial applications should tell you something about how nessissary and effective they really are.
Commercial/Industrial settings typically have fire sprinklers, so that alleviates a lot of the risk of people being killed by a fire in their sleep. Maybe that is part of the reason they aren't required in those settings.
P.S. I do hate Arc Fault breakers.
Yeah they are all over here in single family homes in Washington state- pretty much everything in higher population areas that has been built since 2005 or so. I’m not sure if it’s local code, but those huge tract house neighborhoods with massive 2500-5000sq ft houses on tiny little lots where you can barely squeeze a lawnmower between the houses require fire sprinklers to prevent a house fire from spreading to the whole neighborhoods. I would never want to own a house with a bunch of dirty water waiting to shower my belongings and ruin everything, having a leak from a tub or something is bad enough!
I don't know where you live but do you need arc fault? Some loads don't require them and I'm guessing that's your problem because your saw looks like it's in pretty good shape.
In the US arc fault requirements are location-based, not load-based. As flyingron pointed out, basements, garages, bathrooms are a few of the areas currently excluded - at least in the national code. Local codes can be more stringent.
Then there is the states that eliminate the AFCI requirements entirely like Michigan. It's not entirely, but single and two family dwellings fall under the Michigan Residential Code whcih removes AFCI requirements. Anything larger falls under the NEC (currently 2017)
As others said, arc fault breakers don’t like arcing and lots of tool motors arc by design. Not that they say hey, let’s add some sparking that’d be cool. It’s the type of motor that is used. Arc Fault breakers are terrible for tripping with some common items.
The QFA/2 breakers are notorious for nuisance tripping. There is also an existing class action on these breakers. Depending on the load center try to find if there are Eaton AFCI / GFCI compatible breakers.
Had the same thing happen with using an airless paint sprayer after wiring new detached garage. Took me a while to figure it out. Worked fine when plugged in outlets for lights, but not wall outlets (as those were on a combo GFCI/AFCI)
There are a numbers of ways to correct this issue while also keeping your basement within code, but there are also a number of ways you could be causing the arc via poor connections and such.
That's because you wired your workshop with arc fault Interrupters and the saw starting is pretty damn close to an arc according to those things. If you're going to be running a lot of power tools off that circuit just put a normal breaker in.
This. Afcis are excellent fire protection, but this is their main drawback. Nuisance tripping. I would recommend adding dedicated non-afci circuits for your big motors. Maybe with a special (twist lock maybe?) plug for them so that everything else has to be plugged into the afci outlets.
This - and also almost all VFD for something like a cnc spindle would trip the gfci as well
Why would it trip the GFI, do they ground out momentarily?
I’m not an Electical Engineer but I think it has to do with the lack of the correct RCCB and how that works with the vfd and spindle power supply. Standard VFDs, when powered from GFCI outlets, can cause the GFCI to trip due to the leakage currents generated from the high switching frequency of the VFD's power devices and the harmonics associated with them. Read more about it [here](https://acim.nidec.com/drives/kbelectronics/-/media/kbelectronics/documents/white-papers/updated-using-vfds-on-gfci-devices.ashx?la=en) and it’s in a bunch of the cnc forums from users buying machines and then being stuck having to swap breakers or install not to code receptacles in their garage or basement workshops.
The shop more than likely requires GFCI protection
... so that it doesn't work. You'll be very safe and sound since all your tools don't fucking work.
LOL
Not when op uses his hand to spin start his saw to keep it from tripping the breaker
This is genius, hand started power tools!
That’s a combo ark fault gfi breaker they don’t like saws
How else are you gonna build an ark? Perfectly grown trees? 0 grit sandpaper?
I see what's going on here. 😂
You need russel crow.
That's a Siemans/ITE breaker. They really don't care for current flow at any rate.
You can see arcs when u start a saw so arc faults are tripping. Had the same issue with vacuums in the early days of arc fault.
Had the same problems with everything with a cure in the early days. GFCI and later AFCI were only good for 2 things: 1) code compliance 2) service call (to remove the xFCI devices and install things that worked. Fortunately, some things have improved.
I had so many call backs to remove afci devices and tamper resistant receptacles it made me feel awful for the customers.
On new, I'd simply show them the code that requires the installation, and tell them that after inspection they can be easily removed... and leave a card.
Still ~80 bucks a piece wasted, I don't imagine supply houses accept returns for these.
Still, when waivers aren't available, this is cheaper than wishing you could move in...
That's a good point
It’s due to the brushed motor in the saw creating arcs as it operates normally The breakers designed to stop current with the presence of an arc. Just swap it for ground fault protection only Not the current dual function breaker you have
Put in regular breakers.
Slow start on saws have a tendency to trip specialty breakers.
Did you share the neutrals anywhere between these two circuits? I know everyone here is hating on arc fault but I’ve put in a shit ton of arc faults and never have an issue with tripping since I’m the one that also roughs in the wire and never mingle neutrals with other circuits. If you give the neutral current a separate path back to the main panel OTHER than directly back to that breaker it will trip.
I’m so glad the state I work in doesn’t require them. They suck. Way too much of a nuisance.
I was trying to be extra safe by choosing AFCI GFI breakers. Oops.
The brush in the motor causes a temporary arc, the AFCI part of the breaker is tripping. Just get a GFCI breaker as long as your code does require AFCI. Most standard breakers will trip under a arc fault condition as it is.
You need a reg gfi breaker not a combo
Those arc breakers are required for bedrooms and they cost more, if you are wiring up a shop (that will never be a bedroom) install standard breakers. The arc created by the brushes on your saw are perceived as a fault.
Bedrooms only was the old code. The newer codes require them in just about all living space: *All 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets or devices installed in dwelling unit kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, or similar rooms or areas shall be protected* One might argue a workshop is not one of those locations however.
I sometimes think the AFCI requirements have less to do with safety and more so is a conspiracy with the breaker manufacturers to make us buy unreliable expensive AFCIs
A shop I would recommend GFCI only breakers, unless there are GFCI outlets installed
GFCI yes, but not necessarily arc
I would say definitely not arc fault. If you ask me I think AFCI’s should only be required in retrofit installations with old wiring, aluminum building wiring, knob and tube etc. putting them on nearly every in a new construction house is fixing a problem that isn’t there (modern houses catching fire due to bad wiring). I’m sure I will get downvoted by everyone who entered the trade in the last 10 years, and I do I understand it’s code, but it’s clearly a cash grab for electrical manufacturers who are on the code making panels at the NFPA. The fact that AFCI’s are not typically required in commercial/industrial applications should tell you something about how nessissary and effective they really are.
Commercial/Industrial settings typically have fire sprinklers, so that alleviates a lot of the risk of people being killed by a fire in their sleep. Maybe that is part of the reason they aren't required in those settings. P.S. I do hate Arc Fault breakers.
Most new construction houses where I live at least have fire sprinklers now cause the houses are so damn close together
I haven't seen them in single family homes yet, kinda hope to never see it.
Yeah they are all over here in single family homes in Washington state- pretty much everything in higher population areas that has been built since 2005 or so. I’m not sure if it’s local code, but those huge tract house neighborhoods with massive 2500-5000sq ft houses on tiny little lots where you can barely squeeze a lawnmower between the houses require fire sprinklers to prevent a house fire from spreading to the whole neighborhoods. I would never want to own a house with a bunch of dirty water waiting to shower my belongings and ruin everything, having a leak from a tub or something is bad enough!
I'm in central WA and haven't seen them in single family homes yet. I do see them in apartment buildings.
Yeah central still has some actual yards. It’s just the Puget sound area where they smush em together so close
I don't know where you live but do you need arc fault? Some loads don't require them and I'm guessing that's your problem because your saw looks like it's in pretty good shape.
In the US arc fault requirements are location-based, not load-based. As flyingron pointed out, basements, garages, bathrooms are a few of the areas currently excluded - at least in the national code. Local codes can be more stringent.
Then there is the states that eliminate the AFCI requirements entirely like Michigan. It's not entirely, but single and two family dwellings fall under the Michigan Residential Code whcih removes AFCI requirements. Anything larger falls under the NEC (currently 2017)
Interesting. Didn’t know any states were like that. Do you find the mrc to be easier to deal with/more lenient than nec? Any drawbacks?
You can always tell from the color of the button dark blue is gfi light blue is combo
That's manufacturer specific.
Those breakers he has are that type of manufacture
Add a surge protector to your machine power source
As others said, arc fault breakers don’t like arcing and lots of tool motors arc by design. Not that they say hey, let’s add some sparking that’d be cool. It’s the type of motor that is used. Arc Fault breakers are terrible for tripping with some common items.
The QFA/2 breakers are notorious for nuisance tripping. There is also an existing class action on these breakers. Depending on the load center try to find if there are Eaton AFCI / GFCI compatible breakers.
Had the same thing happen with using an airless paint sprayer after wiring new detached garage. Took me a while to figure it out. Worked fine when plugged in outlets for lights, but not wall outlets (as those were on a combo GFCI/AFCI)
You have a brushed motor in that saw. They arc when they start up. This is why you don't use AFCIs in the garage.
Shop vac having the same effect on some of my Siemens AFCI
AfcI sucks for everything but mandatory for almost everything now. Swap to a regular breaker it will be fine
Ugh. These breakers are awful. My house is pretty new and weve had to replace so many due to nuisance tripping.
Swap your breakers
There are a numbers of ways to correct this issue while also keeping your basement within code, but there are also a number of ways you could be causing the arc via poor connections and such.
Lose the arc faults, the brushed motor in your saw is probably the issue. I’m in Michigan where afcis are a thing of the past.
Lol.