Electrical requirements for Hammer A3-31.

[Darren Brown]

Whats up guys,

This post might belong in the workshops section so mods. please feel free to move it. I'm looking to find out the electrical requirements of an A3-31. The setup manual says you need to have a 30 amp circuit. Based on the actual requirements of the jointer/planer, I'm thinking this may be overkill. Right now I have a 20 amp circuit running in my shop with 12-2 wire, 20 amp plugs, receptacles, etc. An upgrade to 30 amp. means 10-2 wire, new plugs and receptacles, fishing fat wire through conduit and all the fun that comes with that. I'm trying to avoid it if I can. A little guidance would be much appreciated.

Thanks,

Darren Brown

[Rod Sheridan]

Hi Brian, I have an A3-31 running on a 15 ampere circuit.

It's worked fine for over two years.

Hammer specify the maximum overcurrent protection at 16 amperes, which is a standard size in Europe, so I could have gone with a 20 ampere circuit in Canada.

30 amperes wouldn't meet code requirements in Canada, since the manufacturer specifies a maximum value that could be satisfied by a 20 ampere breaker.

You're going to love your machine...............Regards, Rod.

[bill bruno]

Hi Darren,

To the best of my knowledge a circuit should never run at more than 80% capacity. For example, a 20 amp circuit should have a max load of 16 amps. Hope this helps.

bill

[Darren Brown]

Thanks guys.

[Bijesh Jacob]

Hi, not to hijack this thread. But I have ordered A3-31 and a k3. I have to wire for 220. If I wire for 30 amps can I run both the machines on the same circuit. I will only run one machine at a time. Will the 30amps cause an issue with the 15amp requirement of the a3?

Regards
Bijesh

[Tom W Armstrong]

Hi, not to hijack this thread. But I have ordered A3-31 and a k3. I have to wire for 220. If I wire for 30 amps can I run both the machines on the same circuit. I will only run one machine at a time. Will the 30amps cause an issue with the 15amp requirement of the a3?

Regards
Bijesh

Hey Bijesh,

The plugs/receptacles would be different for 30 amp (compared to the Hammer 20 amp plugs), but it wouldn't "hurt" anything as long as you use the 10-2 wire for it. I would just have them provide two 20 amp receptacles on the same circuit if you're not running at the same time. That's what I do.

[Rod Sheridan]

If the manufacturer specifies a maximum overcurrent protection value, the electrical code in Canada requires you to follow it regardless of what the code may otherwise allow.

I doubt if the American code would be different, code recognises that manufacturers of equipment know more about the specific equipment than the general code does.

Regards, Rod.

[Roger Jensen]

You probably either already know this or you may read the fine print on your warning label, but be sure to hold in the start button on the A3-31 until it is up to speed. I am running mine on a 20 amp circuit and was flipping the breaker on start up. I thought I needed more amps, but I only had to hold in the button longer.

Sorry if you already knew this (I obviously didn't).

Roger

[Bijesh Jacob]

Hey Bijesh,

The plugs/receptacles would be different for 30 amp (compared to the Hammer 20 amp plugs), but it wouldn't "hurt" anything as long as you use the 10-2 wire for it. I would just have them provide two 20 amp receptacles on the same circuit if you're not running at the same time. That's what I do.

Thanks Tom. I understood that the machines did not come with plugs and I would need to wire them. So I was looking to get an electician to add a 30amp circuit and then I would install 2 30 amp receptacles and plugs from HD.

Bijesh

[Rod Sheridan]

Thanks Tom. I understood that the machines did not come with plugs and I would need to wire them. So I was looking to get an electician to add a 30amp circuit and then I would install 2 30 amp receptacles and plugs from HD.

Bijesh

Hi Bijesh, before you do that, check what the maximum size breaker is allowed for the Hammer. I doubt if a 30 ampere breaker is allowed.

Regards, Rod.

[Darren Brown]

Just heard back from Geoffrey at Felder. He said they recommend a 20 amp circuit with a 20 amp "slow burn" breaker so I'm golden. Question now is, what is a "slow burn" breaker?

Darren

[Rod Sheridan]

It's what you have in your panel, it has an inverse time characteristic that trips faster as the overload increases in magnitude.

Regards, Rod.

And if you forget to hold the start button until the machine is up to speed, you'll get to verify the trip function of your breaker:D

[Bijesh Jacob]

Thanks guys. I will get a 20 amp breaker installed and hopefully remember to hold the button down when I get my machine :)

[Todd Zucker]

I am hopefully not hijacking this thread, but have what appears to be a closely related question. I am trying to plan the electrical connection for a Hammer A3-31 that is being delivered soon.

Our garage has a 220V NEMA 14-30 outlet (i.e., an electric clothes dryer outlet) that is supposed to be used as an electric car charger. We don’t have an electric car and don’t use the outlet, and I think the builder really wanted me to just put a Hammer in the garage.

The outlet is protected at the panel by tandem 30 amp breakers.

I was going to put a Turnlok plug on the A3, and then make an extension cord with about 10 feet of 12 gauge wire with a Turnlok connector on one end and a plug on the other end that will fit into the 14-30 outlet.

However, I see that the 30 amp breaker requires 10 gauge wire, and also that the A3-31 requires a 20 amp breaker. Could we just replace the 30 amp breakers in the panel with 20 amp breakers and use the rest of the setup described above.

I also saw a post from Paul Marcel (half inch shy) where he used all 4 wires from the 14-30 outlet and created an extension cord with a 2-gang metal box that had a 240V outlet for the big machine and a 110V GFCI outlet for the router, etc. Is that a good idea?

Whatever I do, I am going to have an electrician bless it and perhaps install it, but I was wanting to get the stuff thought out in advance.

[Ben Rivel]

I am hopefully not hijacking this thread, but have what appears to be a closely related question. I am trying to plan the electrical connection for a Hammer A3-31 that is being delivered soon.

Our garage has a 220V NEMA 14-30 outlet (i.e., an electric clothes dryer outlet) that is supposed to be used as an electric car charger. We don’t have an electric car and don’t use the outlet, and I think the builder really wanted me to just put a Hammer in the garage.

The outlet is protected at the panel by tandem 30 amp breakers.

I was going to put a Turnlok plug on the A3, and then make an extension cord with about 10 feet of 12 gauge wire with a Turnlok connector on one end and a plug on the other end that will fit into the 14-30 outlet.

However, I see that the 30 amp breaker requires 10 gauge wire, and also that the A3-31 requires a 20 amp breaker. Could we just replace the 30 amp breakers in the panel with 20 amp breakers and use the rest of the setup described above.

I also saw a post from Paul Marcel (half inch shy) where he used all 4 wires from the 14-30 outlet and created an extension cord with a 2-gang metal box that had a 240V outlet for the big machine and a 110V GFCI outlet for the router, etc. Is that a good idea?

Whatever I do, I am going to have an electrician bless it and perhaps install it, but I was wanting to get the stuff thought out in advance.
Yea this really should have an electrician look it over, but a couple points here. A typical electric dryer circuit in a home uses a four wire plus gound connector which has the two 220V you want, a 120V and a neutral which you dont need. So in order to deal with "downsizing" that connection you would need to safely deal with the live 120V and neutral wire somewhere. Also an extension cable for the circuit would have to be 10awg. You can also have a higher current breaker and larger gauge wire going to a machine than it needs. Its only going to pull what it can. Anything more isnt going to hurt it. Its UNDERsizing the circuit that you dont want to do.

[Dan Friedrichs]

Todd, this is a 7-year-old thread, so I doubt you'll hijack it :)

The breaker should be sized to protect the wire, not the appliance connected to it. So if you have 10AWG wire (which would typically be rated for 30A), and a receptacle rated for 30A, you should leave the 30A breaker alone. While there is nothing dangerous about downsizing it to 20A, there's also no point to doing that. Think about it - you don't go change the breaker size when you plug in different appliances in your kitchen, do you? Same situation, here.

It would be perfectly fine to make a pigtail with a 14-30 plug on one end and a L5-20R or L5-30R on the other end. You can also make the "splitter" box you propose, if you happen to be lacking other 120V receptacles and would find it convenient.

[Dan Friedrichs]

Also an extension cable for the circuit would have to be 10awg.

This is not necessarily true. I assume you think it needs to be 10AWG because of the 30A breaker. In most situations, NEC would require that wiring installed in a residence be 10AWG for a 30A circuit. However, it doesn't apply to the appliance and associated cord.

I'd size the cord to match whatever is provided on the machine.

[Ben Rivel]

This is not necessarily true. I assume you think it needs to be 10AWG because of the 30A breaker. In most situations, NEC would require that wiring installed in a residence be 10AWG for a 30A circuit. However, it doesn't apply to the appliance and associated cord.

I'd size the cord to match whatever is provided on the machine.Just suggested to play it safe. That way the extension cord could be used with any device all the way up to the circuits max at 30A.

[Dan Friedrichs]

Yep, no harm in making it bigger (as you said). But the NEC calculation that usually results in needing a 10AWG conductor for a 30A circuit is based on the idea that the resistance of the wire produces a certain amount of heating, and given some worst-case scenario (ie - multiple wires all simultaneously carrying max current in a tight conduit in a hot attic in an Arizona summer and laying right up against some highly-combustible material), 10AWG is the smallest size that results in a safe steady-state temperature (plus an enormous safety margin). But for a cord that is laying on the floor with nothing insulating it, the safe limit is much lower. There's nothing about 30A that requires 10AWG - It's common to use smaller wire, since the appliance cord is typically quite short and doesn't have the same thermal constraints/assumptions.

[Rod Sheridan]

Todd, this is a 7-year-old thread, so I doubt you'll hijack it :)

The breaker should be sized to protect the wire, not the appliance connected to it. So if you have 10AWG wire (which would typically be rated for 30A), and a receptacle rated for 30A, you should leave the 30A breaker alone. While there is nothing dangerous about downsizing it to 20A, there's also no point to doing that. Think about it - you don't go change the breaker size when you plug in different appliances in your kitchen, do you? Same situation, here.

It would be perfectly fine to make a pigtail with a 14-30 plug on one end and a L5-20R or L5-30R on the other end. You can also make the "splitter" box you propose, if you happen to be lacking other 120V receptacles and would find it convenient.

Hi Dan, what you said is perfectly correct, except in the case of my A3 it came with a warning that overcurrent protection was not to exceed 20 amperes. In that case you can't plug it in to a 30 ampere circuit.

Mine also came with a warning that fault currents had to be no more than 5KA, no problem at my house.........Regards, Rod.

Regards, Rod.

[Todd Zucker]

Thanks. That all makes sense. Maybe I could put a 20 amp breaker on the splitter box and keep the wall outlet and panel intact.

[Dan Friedrichs]

I mean, you could, but realize that the spec for a 20A overcurrent protection on the machine also has a safety margin built in, and the odds that you somehow manage to damage the motor by producing fault or operating condition that draws more than 20A (but less than 30A) is really, really small. I'd be more worried about getting hit on the head by a falling meteor while driving to the hardware store to buy the parts...

[Art Mann]

Trust Dan!

[David L Morse]

Regarding extension cord sizing, this, from the NEC, might be interesting:
352305
As others have pointed out the cord is sized to the load, not the circuit that supplies it. Consider that most table lamps are equipped with 18 gauge wire and are plugged into either 15 or 20A receptacles. A "Standard" household extension cord is typically 18 gauge while a "Heavy Duty" one is 16 gauge. (I know, this is troll bait.:eek: I'm not saying it's ok to overload an extension cord, just trying to provoke some thinking about how they're sized and used.)

[Rod Sheridan]

Trust Dan!

Although in general that's good advice, in the case of my machine it would be illegal.

The manufacturer's specifications have precedence over code, in my case the certification organization of the equipment has prohibited more than 20 Amperes overcurrent protection, and that fault currents must not exceed 5,000 amperes.

No general advice can supersede those instructions..............Regards, Rod

[Rich Riddle]

I tend to make one long "shop" extension cord for each particular amperage outlet; that is, I tend to make a 10 gauge extension cord for a 30 amp circuit. That way, I am not housing many extension cords. If your extension cord is always superior to your appliance, you can always use it. It makes life easier. So in this case for the Hammer, I would have a 10 gauge extension cord. It would also work with other 220 volt tools.

[Art Mann]

I have noticed before that Canadian requirements are significantly different from those in the US.


Although in general that's good advice, in the case of my machine it would be illegal.

The manufacturer's specifications have precedence over code, in my case the certification organization of the equipment has prohibited more than 20 Amperes overcurrent protection, and that fault currents must not exceed 5,000 amperes.

No general advice can supersede those instructions..............Regards, Rod

[Todd Zucker]

Dan, a funny thing happened when I was in the car heading to the hardware store today... :o.
Rich, great idea, but I bought the 12 AWG before I saw your post. With the rubber coating, my car now smells like a giant brand new festool systainer.
Rod, I am definitely calling an electrician before I plug this thing in. I have no idea about fault currents.

[Dan Friedrichs]

Although in general that's good advice, in the case of my machine it would be illegal.

The manufacturer's specifications have precedence over code, in my case the certification organization of the equipment has prohibited more than 20 Amperes overcurrent protection, and that fault currents must not exceed 5,000 amperes.

No general advice can supersede those instructions..............Regards, Rod

I forget you're Canadian, sometimes, Rod! :)

Not to get political, but sometimes I wish the types of rules implemented by CSA were more widely adopted around the world. Every time I plug in a cheap piece of electronics, I can't help but wonder if some overseas "engineer" decided to omit a 10-cent fuse to make it just a bit cheaper. I'd probably sleep better at night if I were also a Canadian, in that regard :)

[Matt Mattingley]

When I received my A31 in the instruction manual it specifically stated to be fed no more than 20 A. It came with 16 inches of cut off 12g. As Rod pointed out it is a 16 FLA motor. The wiring in the machine is only rated for 20 A max. So by putting upstream 20A breaker, only makes sense. A machine is not quite rated like A lamp. Lamps don't need lock rotor specifications. Most lamp manufactures give a little silly sticker on the side of it to not exceed so many watts in bulbs. Not following manufactures suggestions falls on your own shoulders. If you actually care about your machine, your lamp, the building they reside in, follow the manufacturers maximum suggestion.

[Van Huskey]

The weird thing is, in the US at least, you see all manner of odd versions of how to wire a machine in manuals. One company has 2 TS, one listed at 14 FLA and lists a 15a circuit as minimum which is OK if plugged in but has code issues if hardwired, the other saw is listed at 12.8 FLA but lists a 20a circuit as the minimum. It is actually unusual to see a (5hp or less) woodworking machine sold in the US with maximum over-current protection listed, it is almost always the minimum.

[Dan Friedrichs]

When I received my A31 in the instruction manual it specifically stated to be fed no more than 20 A. It came with 16 inches of cut off 12g. As Rod pointed out it is a 16 FLA motor. The wiring in the machine is only rated for 20 A max. So by putting upstream 20A breaker, only makes sense. A machine is not quite rated like A lamp. Lamps don't need lock rotor specifications...

I agree that it won't hurt, and it's definitely an additional layer of "idiot proofing", but presumably no one actually locks the rotor on a jointer. If you got anywhere near 16A, the motor would start to bog down, and the user would know to "back off". If I were taking much too heavy of cut on a planer, my personal preference would be for the motor to bog down, rather than the breaker trip.

[Ben Rivel]

FWIW I called the west coast Hammer/Felder office on Friday and spoke to the lady that always helps me with my Hammer questions and she stated very clearly that Hammer always recommends a 20A circuit for the N4400 bandsaw and A3-31 jointer/planer. They have the same motor and I have been running my N4400 on a 20A circuit since I got it and haven't once had an issue.

[Art Mann]

I have to disagree with Dan that locked rotor is an unusual condition. I would say it is the most common cause of an electrical over-current in a typical wood shop. For example, if you are ripping a large sheet of plywood or maybe a hardwood plank with unexpected internal stresses, it is relatively easy to get into a situation where a pinch or wedge causes the motor to stall unexpectedly. What is worse, if you turn loose of the work piece to slam the E-stop, you may cause a worse situation. This has happened to me several times over the 30+ years I have been woodworking and I have seen other people experience the same thing. In such a situation, the thermal overload protection built into the motor will normally shut the motor off long before the breaker trips. If this doesn't happen, it is very unlikely that a breaker will save the motor. Here's why.

Everyone who assumes that a breaker is designed to protect the device plugged into it should take the time to download the "trip curve" of the breaker they are using and study it carefully. Breakers don't open up the instant the rated current happens. At that level, the breaker might not open up at all. Their response is defined by this curve, which plots breaker response time as a function of over-current level. Typically, a breaker will hold for a minute or more at double the rated current. It will even sustain 10 times the rated current for several seconds. The wire used for the windings is much, much smaller than the wire used to feed the motor. This is because designers want to keep the motor small and almost all of the power in a motor is dissipated as mechanical motion rather than as heat. When you lock the rotor, almost all the energy goes into heating the windings. In the time it takes for the breaker to open, your motor could already be lost were it not for thermal overload protection.

Breakers must be designed according to a trip curve. The starting current of a motor is much higher than the full load amps stamped on the housing. This is a problem which can't be designed away easily and it is impossible for motors starting under load. Breakers are designed to accommodate this phenomenon.

As an aside, incandescent bulbs also have a starting current that is much higher during the several milliseconds it takes to heat the filament to a steady state.

[Sean Tracey]

The weird thing is, in the US at least, you see all manner of odd versions of how to wire a machine in manuals. One company has 2 TS, one listed at 14 FLA and lists a 15a circuit as minimum which is OK if plugged in but has code issues if hardwired, the other saw is listed at 12.8 FLA but lists a 20a circuit as the minimum. It is actually unusual to see a (5hp or less) woodworking machine sold in the US with maximum over-current protection listed, it is almost always the minimum.

Circuit Breakers in a house are designed to protect the wiring attached to it by limiting the current to a maximum.

A machine has to be able to draw a certain amount of current without constantly flipping the house breaker.

Since components in the machine also must be protected from overcurrent, it makes sense that the machine have it's own breakers and/or fuses to protect the machine with the specific overcurrent protection and speed of overcurrent protection necessary.

This would allow you to have your wiring set up to feed various machines of various power requirements while the machine protects itself as necessary.

If a machine is supplied with a certain type of outlet, then that outlet typically is rated for a certain amount of amps, so if the machine can handle that amount of amps then perhaps no additional specification is necessary. Or if it is, then the manufacturer can add circuit protection to protect the machine.

If a machine is not supplied with a certain type of outlet, then the manufacturer would have to specify the maximum circuit breaker of the house wiring. Frankly, I think that's a poor way of doing it. The machine should have it's own protection so you don't have to limit an entire circuit to 20 amps when 30 amps is a common breaker size for 220V wiring in the country the machine will be installed.

I'm not an electrician, so perhaps there is some reason a manufacturer would specify the house circuit breaker that I am unaware of.

[Rod Sheridan]

Sean, almost all electrical equipment has maximum overcurrent ratings specified by the manufacturer. (Not consumer stuff).

The equipment will give different ratings depending upon whether you're using a molded case breaker, a standard fuse or current limiting fuses.

There are no standard sizes for feeders, aside from the variety of overcurrent ratings available, so you need a feeder that's sized properly.

This is to take into account the short circuit and withstand ratings for the components of the machine.

This is standard practice and is something the Engineer has to take into account of on every installation..........Rod.

[Van Huskey]

Circuit Breakers in a house are designed to protect the wiring attached to it by limiting the current to a maximum.

A machine has to be able to draw a certain amount of current without constantly flipping the house breaker.

Since components in the machine also must be protected from overcurrent, it makes sense that the machine have it's own breakers and/or fuses to protect the machine with the specific overcurrent protection and speed of overcurrent protection necessary.

This would allow you to have your wiring set up to feed various machines of various power requirements while the machine protects itself as necessary.

If a machine is supplied with a certain type of outlet, then that outlet typically is rated for a certain amount of amps, so if the machine can handle that amount of amps then perhaps no additional specification is necessary. Or if it is, then the manufacturer can add circuit protection to protect the machine.

If a machine is not supplied with a certain type of outlet, then the manufacturer would have to specify the maximum circuit breaker of the house wiring. Frankly, I think that's a poor way of doing it. The machine should have it's own protection so you don't have to limit an entire circuit to 20 amps when 30 amps is a common breaker size for 220V wiring in the country the machine will be installed.

I'm not an electrician, so perhaps there is some reason a manufacturer would specify the house circuit breaker that I am unaware of.

I am not sure what the Pre-Wiring 101 class had to do with my observation. Most of us understand the idea of in-wall wiring and how that relates to home/shop over current protection. My point was the breaker suggestions even within one importer's tools is all over the place. In the case sighted they were both table saws with low starting torque and fast ramp up to synchronous speed so the in-rush should not be unusually high and should drop to no load very quickly so I found the breaker recommendations odd. They both include plugs so that avoids any code issues with the 15 amp recommendation since one would have to modify the machine to hardwire it, if hardwire the 14 FLA TS would require a 20 amp breaker.

With that out of the way, what hits me about this thread is what makes the Hammer machine "unusual" or different. In most every modern US home we have dozens of devices plugged into duplex outlets on 20 amp breakers (most outlets are technically 15a per receptacle but OK because it is considered 2 devices) that draw much less than 15a often small fractions of an amp. Most of our woodworking machines have suggested minimum over-protection (all my machines of European origin are the same but I have no Felder machines). So why does Felder approach the issue from the opposite direction, is there a difference in their onboard over-current protection or is it merely a difference in approach more a suspenders and belt safety approach?

[Matt Mattingley]

With that out of the way, what hits me about this thread is what makes the Hammer machine "unusual" or different. In most every modern US home we have dozens of devices plugged into duplex outlets on 20 amp breakers (most outlets are technically 15a per receptacle but OK because it is considered 2 devices) that draw much less than 15a often small fractions of an amp. Most of our woodworking machines have suggested minimum over-protection (all my machines of European origin are the same but I have no Felder machines). So why does Felder approach the issue from the opposite direction, is there a difference in their onboard over-current protection or is it merely a difference in approach more a suspenders and belt safety approach?

Van, Are you suggesting that your electrical code allows for you to put 5–15 outlet on a 20A Circuit? We're not allowed to do that. If it is a 20 amp circuit, we need to install a 5-20 outlet as the outlet has a NEMA/CSA rating, which completes the circuit. We usually only have 5–20 outlets in high consumption areas (kitchens, shops, garages) which are inspected by our electrical safety authority.

When you get into industrial equipment which Felder is. Yes they have their Hammer line (which is considered homeowner grade) but they have not change their attitude by leaving plugs off the equipment delivered. In the manual it states any electrical should be done by qualified personnel. Most qualified personnel will read the electrical requirements. The electrical requirements stated by the manufacture supersede local code usually. Now if this machine was to be installed in a industrial situation, a qualified industrial electrician (and maybe EE might be involved) for proper industrial set up. I've come across a situation more than once when the new motor nameplate only has this kind of information.
352405
Edit; this machine didn't come with a plug either. But there's always some wise guy out there that thinks that they can put a 40 amp stove plug on this and it's good to go.

[Dan Friedrichs]

Matt, where are you located? I'd bet that 99% of duplex outlets installed in the US are 5-15 wired with 12AWG to a 20A breaker. A duplex receptacle is considered multiple receptacles, which is why it is allowed.

That said, this thread has gotten ridiculous. The breaker is not intended to protect the equipment, and if you think you need an EE to bless installing a plug on something, you're crazy (and I say that being a PhD EE, myself). The OP wanted to know if he should change the breaker from 30A to 20A. The answer is "no, that's not necessary". End of story.

[Matt Mattingley]

Matt, where are you located? I'd bet that 99% of duplex outlets installed in the US are 5-15 wired with 12AWG to a 20A breaker. A duplex receptacle is considered multiple receptacles, which is why it is allowed.

That said, this thread has gotten ridiculous. The breaker is not intended to protect the equipment, and if you think you need an EE to bless installing a plug on something, you're crazy (and I say that being a PhD EE, myself). The OP wanted to know if he should change the breaker from 30A to 20A. The answer is "no, that's not necessary". End of story.
Canada. And if you have a PhD in EE you know how important it is with machine specs from other PhD's in EE. And EE's with NEMA/CAS organizations. If you have a PhD in EE do you think NEMA/CSA requirements can be overlooked?

[Van Huskey]

Van, Are you suggesting that your electrical code allows for you to put 5–15 outlet on a 20A Circuit? We're not allowed to do that. If it is a 20 amp circuit, we need to install a 5-20 outlet as the outlet has a NEMA/CSA rating, which completes the circuit. We usually only have 5–20 outlets in high consumption areas (kitchens, shops, garages) which are inspected by our electrical safety authority.

When you get into industrial equipment which Felder is. Yes they have their Hammer line (which is considered homeowner grade) but they have not change their attitude by leaving plugs off the equipment delivered. In the manual it states any electrical should be done by qualified personnel. Most qualified personnel will read the electrical requirements. The electrical requirements stated by the manufacture supersede local code usually. Now if this machine was to be installed in a industrial situation, a qualified industrial electrician (and maybe EE might be involved) for proper industrial set up. I've come across a situation more than once when the new motor nameplate only has this kind of information.
352405


Edit; this machine didn't come with a plug either.


To the first question, yes. In fact almost all modern homes have the majority (read as it is unusual to see anything different) of 120v circuits wired with 15 amp duplex outlets on 20 amp circuits (12/2 and 20 amp breakers) the key is being a duplex outlet if it is an (odd) single outlet it would have to be wired to a 15 amp breaker. The standard US 15 amp outlet will have two 5-15 receptacles BUT the outlet MUST have 20 amp pass through (to be wired on a 20 amp circuit) but I have yet to see a duplex 5-15 receptacle for sale (recently) without 20 amp pass through but you might be able to find them. It is extremely unusual to find a US portable electric device with a 5-20 plug on it since you almost never see 5-20 receptacles in homes.

I still find the Hammer approach to be the exception rather than the norm for single phase up to 7.5hp equipment that I have run into, all of them simply list the minimum circuit vs a maximum over current protection and often the minimum circuit is rather high when viewed against the FLA and locked rotor draw of the machine. On the larger equipment (albeit older US iron) the manuals tend to just repeat the FLA of the motor and leave the wiring electrician to determine the proper circuit requirements using the motor plate(s).

Maybe this is some commentary on the difference between Italian/US engineers (or manual writers) and Austrian/German/Swiss engineers where if one glass of vino is good, two must be better. < don't read into this, just grinning as I write it

[Van Huskey]

That said, this thread has gotten ridiculous. The breaker is not intended to protect the equipment, and if you think you need an EE to bless installing a plug on something, you're crazy (and I say that being a PhD EE, myself). The OP wanted to know if he should change the breaker from 30A to 20A. The answer is "no, that's not necessary". End of story.

First, I 100% agree with you and while I have wired and passed inspection both homes and shops I have no formal training so my opinion only a micron above worthless. The thing I find intriguing is the difference between Felder's and SCMI's (and most of the others) approach to specifying circuit size. Is there something different about the Felder/Hammer machines or is it simply the engineers/manual writers approach?

[Matt Mattingley]

Van, I agree with you 100% and I have enjoyed reading your last two posts! Maybe there is a little bit of difference between European EE requirements and of those met in North America. I know most of the stuff we ship from Canada to Mexico, US, Sweden, Germany and Japan has our requirements built right in from our EE. If their EE wants to overlook it, that's up to them.

[Sean Tracey]

I am not sure what the Pre-Wiring 101 class had to do with my observation. Most of us understand the idea of in-wall wiring and how that relates to home/shop over current protection. My point was the breaker suggestions even within one importer's tools is all over the place. In the case sighted they were both table saws with low starting torque and fast ramp up to synchronous speed so the in-rush should not be unusually high and should drop to no load very quickly so I found the breaker recommendations odd. They both include plugs so that avoids any code issues with the 15 amp recommendation since one would have to modify the machine to hardwire it, if hardwire the 14 FLA TS would require a 20 amp breaker.

With that out of the way, what hits me about this thread is what makes the Hammer machine "unusual" or different. In most every modern US home we have dozens of devices plugged into duplex outlets on 20 amp breakers (most outlets are technically 15a per receptacle but OK because it is considered 2 devices) that draw much less than 15a often small fractions of an amp. Most of our woodworking machines have suggested minimum over-protection (all my machines of European origin are the same but I have no Felder machines). So why does Felder approach the issue from the opposite direction, is there a difference in their onboard over-current protection or is it merely a difference in approach more a suspenders and belt safety approach?

Well, I agree with you that Felder's approach is different from other manufacturer's like Grizzly. I thought the background info was necessary to get everyone on the same page.

You can download Grizzly's manual for the 490 jointer and it tells you to make sure that the circuit is at least rated for 20 amps. This makes sense to me to specify a minimum circuit rating because you don't want the machine installed on a circuit that is not able to supply the machine. As someone posted, it takes time for a circuit breaker to blow and operating a machine that will pull too many amps on a circuit that is not rated for it is trouble.

It also tells you that if the machine is not on a dedicated circuit that the other loads must be considered in sizing the circuit. Say you had a jointer and a dust collector on the same circuit, If both machines are plug in's, I believe it is okay to have more than one machine on the circuit (Not sure about this and even if I was, it may be different under different jurisdictions). If you did that, though the circuit would now need to be able to supply both machines with sufficient amps. You also probably wouldn't want them to start simultaneously. Grizzly tells you if you have more than one machine on the circuit to have a professional advise you.

So Grizzly does not specify a maximum circuit breaker and I believe the reason why is that the machine has it's own overcurrent or thermal protection that will protect the machine rather than to rely on the house breaker. I do not know if this is true, I am just pondering whether this is the case. Maybe an electrician is on this site and has familiarity with the equipment and can enlighten us.

This leads me to believe that the Hammer machine does not have it's own overcurrent or thermal protection and that's why they specify a maximum circuit breaker. Again, I don't know if this is true or not. I also find it odd that you have to hold the button in until the machine comes up to full speed. I don't think you have to do that with the Grizzly. I know we didn't have to do that with any of our industrial machines but they were three phase. It may be a difference in the starter's that are used. Perhaps Grizzly uses a NEMA starter and Hammer uses an IEC starter. A magnetic starter ensures that the machine will not restart on it's own if power from the circuit is lost and then comes on by itself. I believe some starters also provide overcurrent or thermal protection and maybe Grizzly's starters have this protection and Hammer's do not.

To me, it would seem the best way is to specify a minimum house breaker and then manufacture the machine with it's own overcurrent or thermal protection as necessary to protect it. The reason for this is that the machine would work if somebody installed it on a 30 amp breaker instead of a 20 amp breaker and if it has it's own 20 amp protection it would be protected.

On industrial machines it may be common to hardwire the machine to a power disconnect at the wall which would be fitted with the breaker or fuses that protect the machine. The Hammer doesn't come with a plug, so perhaps that is the intention. The Grizzly does come with a plug, so perhaps mobility was considered and the machine may have it's own protection.

Hopefully, someone who is qualified can answer these questions.