Breaker question

[Craig D Peltier]

I have a 30amp breaker running my 220 outlet. I need a 35 amp or bigger. Not sure of they make a 35 in the brand thats in my box so maybe a 40 or 50. Will there be any issues i.e. wiring gauge by upping breaker amp? It will only be running one tool at a time. Currently I run a 3hp TS off of it or a 220 volt heater or a 5hp 20" planer. Nothing pops it.
The sander I want to hook up to it runs onload at 30 amps and the conveyor I think 2 amps.

Thanks

[Aaron Wingert]

You can't just roll out one breaker and replace it with one of a greater ampacity. The breaker exists for the sole purpose of protecting the wire from overload (melting, fire, etc).

We need to know your wire size going to the 220v receptacle.

[Rick Prosser]

+1 on what Aaron said - and what current does the sander pull normally? You don't need to size the breaker to match the inrush current.

If you increase the breaker size, you will allow more current to flow and heat up the wires. If the wires are not rated for the additional current, you can cause a fire when the wires get hot and melt the insulation.

[Jim Terrill]

The math roughly works out to a 10hp motor. What is the thing, a 60" wide sander?

[Craig D Peltier]

Its a G9983 grizzly sander. At max load it draws 30amps and the conveyor motor runs at 1.8amps.So 31.8 amps.
Hope that helps with more info. I still have to check if wire gauge is 8 or 10 etc.

[Rollie Meyers]

2 questions, 1) is this machine hard wired? 2) is NM cable used?

If yes to # 1 & no to # 2,the motor rules are different , and 10AWG is rated for 35A .This is allowed by NEC article 430 but if NM cable is used it's still limited to 30A by art. 334.80.
BTW, a 35A circuit breaker is a "standard size" but will not be likey to be stocked & certainly not going to be stocked in a big box store.

[Craig D Peltier]

2 questions, 1) is this machine hard wired? 2) is NM cable used?

If yes to # 1 & no to # 2,the motor rules are different , and 10AWG is rated for 35A .This is allowed by NEC article 430 but if NM cable is used it's still limited to 30A by art. 334.80.
BTW, a 35A circuit breaker is a "standard size" but will not be likey to be stocked & certainly not going to be stocked in a big box store.

The machine is not hardwired.I know the current cord on it is #10 . I still havent had time to take break panel off yet to see what gauge wire is going to it. I will in the next 2 hours.

Not sure what NM cable is. I have done some wiring but I wont touch the panel without someone else here that knows whats what.

[Rollie Meyers]

The machine is not hardwired.I know the current cord on it is #10 . I still havent had time to take break panel off yet to see what gauge wire is going to it. I will in the next 2 hours.

Not sure what NM cable is. I have done some wiring but I wont touch the panel without someone else here that knows whats what.

NM cable is commonly called by the brand name "Romex".

[Craig D Peltier]

The gauge wire on the 30amp circuit currently is 10-3 NM-B. Will this hold a 35 or 40amp breaker?

[Gary Click]

Not in my shop.

gary

[Rollie Meyers]

The gauge wire on the 30amp circuit currently is 10-3 NM-B. Will this hold a 35 or 40amp breaker?

Nope, NM cable is limited to the 60 degree ampacity, if THHN then the rules could allow it, if certain conditions are met, per article 430 10 AWG is rated at 35 amperes, but as said earlier with NM cable it is not going to be OK to do that, pull it out & run a larger cable, don't oversize it because then you open another can of worms with NEC article 250.122(B) requiring the grounding conductor to be increased in size if the ungrounded (hot) conductors are increased in size, #6 & 8 NM cables use a 10 AWG grounding conductor, so it won't comply if it's oversized.

[Gary Click]

#10 NM wire is rated at 30Amps, the breaker is ALWAYS sized to protect the wire NEVER to support the load.

Helpful or not, the fact is you can place any size breaker you like in your panel in your shop regardless of any advise or research that you wish to do but you will have to live with the potential consequences. If you oversize the breaker to be able to supply a higher downstream load, the wire overheats, causes a fire and your insurance company refuses to honor a claim this may start to give boundaries to these consequences. If there is injury or loss of life these boundaries expand.

I learned a long time ago that if someone is determined to do something they will regardless of facts, advise or rules. Hence you can do whatever you like but I will not oversize a breaker on a #10 NM or any other gauge wire in my shop. If anything I tend to oversize the wire for a given breaker size, #10 wire on 20A circuits.

If you want a 35, 40 or 50Amp breaker, increase the wire size or wire type to THHN in conduit for example.

[Craig D Peltier]

Nope, NM cable is limited to the 60 degree ampacity, if THHN then the rules could allow it, if certain conditions are met, per article 430 10 AWG is rated at 35 amperes, but as said earlier with NM cable it is not going to be OK to do that, pull it out & run a larger cable, don't oversize it because then you open another can of worms with NEC article 250.122(B) requiring the grounding conductor to be increased in size if the ungrounded (hot) conductors are increased in size, #6 & 8 NM cables use a 10 AWG grounding conductor, so it won't comply if it's oversized.

So should I use and 8 gauge for this even if its NM. Thanks , obviously im green towards this compared to you.I will order a 35amp breaker for its place.I will rewire the old 10 gauge, its only about 3 feet just below the panel. I did the old one.

[Gary Click]

Craig,

If you are going to replace the cable with #8 NM-B, I believe that it is rated at 40Amps at 60C. A 40A Breaker is more common and should be easy to source at a big box store. The kicker may be the recepticle rated at 35A or 40A, you may have to go to a Range type Recepticle and Pigtail.

gary

[Craig D Peltier]

Craig,

If you are going to replace the cable with #8 NM-B, I believe that it is rated at 40Amps at 60C. A 40A Breaker is more common and should be easy to source at a big box store. The kicker may be the recepticle rated at 35A or 40A, you may have to go to a Range type Recepticle and Pigtail.

gary


Thank you , that helps and made me think of the recepticle now :)

[Alan Schaffter]

Craig,

First, I would run the new sander on the circuit you have. If the shop/house is wired correctly*, and it draws too much then the breaker will trip as it should, go protect the wiring and you will know for a fact the draw exceeds the breaker capacity, and likely the wire rating.

You say the sander draws 30 amps- that really means nothing unless accompanied with qualifiers- is that starting, under no load, under normal load, under max load (FLA- full load amps), etc. I suspect under normal load it draws less than that.

* I don't mean to criticize, but judging your questions, you should consult a certified electrician before doing anything, and maybe have him do the work.

[Craig D Peltier]

Craig,

First, I would run the new sander on the circuit you have. If the shop/house is wired correctly*, and it draws too much then the breaker will trip as it should, go protect the wiring and you will know for a fact the draw exceeds the breaker capacity, and likely the wire rating.

You say the sander draws 30 amps- that really means nothing unless accompanied with qualifiers- is that starting, under no load, under normal load, under max load (FLA- full load amps), etc. I suspect under normal load it draws less than that.

* I don't mean to criticize, but judging your questions, you should consult a certified electrician before doing anything, and maybe have him do the work.

Thanks, I also need to say how did you learn? Im just trying to learn. Electrical isnt too dificult im'm just trying to understand it better. Maybe I shouldnt ask questions and just read a book I guess.Since some people just seem to say hire an elecician. Gets me thinking that maybe there electricians or think they are? Im not but I am a full time woodworker and I would like to know how to set something like this up. As I say again I'm not doing this alone. There will be a person here who knows but its not like he's being paid. So the less work the better I see it as.I think there are certified electricians on here. At least there seems to be alot of code and code articles referenced on this post and people who feel confident enough about there electrical abilites.
The sander is based on max load 30amps. So it would just trip sooner I suppose but I dont want to be underpowered. Its the main reason I getting rid of the 16-32 110volt.
All I ask for is simple instruction instead of criticism. Like: No you cant set up a 35 amp breaker without knowing the gauge wire of wire it is and if its a NM or not, based on rating.You need this gauge of wire to handle this.You can just see if it works on that breaker and if doesnt then just change the gauge and up the breaker to 35amps. Also the outlet is rated and you need to know that.I thought Iwasnt on the master electricians forum but a geneal workshop one?
Its all obvious thats its dangerous if you dont know what your doing. So isnt woodworking. I've learned that. I know not to touch the hot wire and have the power off and whats hot and what not and where ground go etc.
Thanks again, just getting fed up with all the sarcasm about electrical questions/answers.
I dont need anymore help.I use this forum to advise with no criticsm and learn as well.Theres a bundle of knowledge on here that we all could learn from.
Thanks for who have helped and didnt get fed up or made sarcastic remarks. When someone is just trying to learn.

[Roger Frazee]

Hi Craig

From the manual

http://media7.dropshots.com/photos/440526/20100318/235900.jpg
Your total load is 32 amps ... as already determined if your using NM cable you will need #8/2 with ground copper. This will have an insulated black, insulated white and bare ground. Your black and white will be your hots wires. You should take a black marker and color the white a few inches on each end where it terminates to identify it as a hot wire. You will need a 35 or 40 amp double pole breaker. You will need a 250 volt nema 6-50 P (Plug) and Nema 6-50R (receptacle).

http://www.jhlarson.com/ind_tables/nema/nema_straight.htm

You will need a device box like this...if mounting to a wood stud ... otherwise no bracket. Get one 2 1/8 inch deep with 3/4 knockouts and one cable clamp. You will need 2 nm clamps the other one will be installed at your breaker panel.

http://s7d5.scene7.com/is/image/HardwareandTools/050169006856?wid=200&hei=200http://www.hardwarestore.com/media/product/238063_front200.jpg

And receptacle ... when you mount it to the device box put the ground at the top so the cord will lay flat to the wall.

http://images.marketworks.com/hi/58/57750/L5374-EA-1.jpg


and plug

http://www.signalandpower.com/images/prod/yp-93l.jpg
If you go to a tool shop you can buy a pre-made power machine cord like shown or make your own with SOW series cord.

[Josh Bowman]

Its a G9983 grizzly sander. At max load it draws 30amps and the conveyor motor runs at 1.8amps.So 31.8 amps.
Hope that helps with more info. I still have to check if wire gauge is 8 or 10 etc.
Craig,
Does it trip the current breaker? If not keep using it. If you'll just check the amp draw with an amp meter, I bet you're well below the nameplate data.

[Craig D Peltier]

Hi Craig

From the manual

http://media7.dropshots.com/photos/440526/20100318/235900.jpg
Your total load is 32 amps ... as already determined if your using NM cable you will need #8/2 with ground copper. This will have an insulated black, insulated white and bare ground. Your black and white will be your hots wires. You should take a black marker and color the white a few inches on each end where it terminates to identify it as a hot wire. You will need a 35 or 40 amp double pole breaker. You will need a 250 volt nema 6-50 P (Plug) and Nema 6-50R (receptacle).

http://www.jhlarson.com/ind_tables/nema/nema_straight.htm

You will need a device box like this...if mounting to a wood stud ... otherwise no bracket. Get one 2 1/8 inch deep with 3/4 knockouts and one cable clamp. You will need 2 nm clamps the other one will be installed at your breaker panel.

http://s7d5.scene7.com/is/image/HardwareandTools/050169006856?wid=200&hei=200http://www.hardwarestore.com/media/product/238063_front200.jpg

And receptacle ... when you mount it to the device box put the ground at the top so the cord will lay flat to the wall.

http://images.marketworks.com/hi/58/57750/L5374-EA-1.jpg


and plug

http://www.signalandpower.com/images/prod/yp-93l.jpg
If you go to a tool shop you can buy a pre-made power machine cord like shown or make your own with SOW series cord.

Thanks Roger for taking the time to post all the pics, very helpful, that NEMA chart is helpful in the future as well.

Right now I use the same 220 receptacle for a 20" planer , a 220 volt coil heater and a 3hp jet tablesaw. Is there any issue with changing all these plug heads on those cords to accomodate the new plug style and receptacle? Plus the wire to 8 gauge?
The single receptacle does work for me since I never run planer and TS together. It is a pain to go back an forth to unplug. I know I can just make a pig tail coming out of it, but my shop is mostly on wheels so I have to roll out planer so its no biggie.

[Alan Schaffter]

Thanks, I also need to say how did you learn? Im just trying to learn. Electrical isnt too dificult im'm just trying to understand it better. Maybe I shouldnt ask questions and just read a book I guess.Since some people just seem to say hire an elecician. Gets me thinking that maybe there electricians or think they are? Im not but I am a full time woodworker and I would like to know how to set something like this up. As I say again I'm not doing this alone. There will be a person here who knows but its not like he's being paid. So the less work the better I see it as.I think there are certified electricians on here. At least there seems to be alot of code and code articles referenced on this post and people who feel confident enough about there electrical abilites.
The sander is based on max load 30amps. So it would just trip sooner I suppose but I dont want to be underpowered. Its the main reason I getting rid of the 16-32 110volt.
All I ask for is simple instruction instead of criticism. Like: No you cant set up a 35 amp breaker without knowing the gauge wire of wire it is and if its a NM or not, based on rating.You need this gauge of wire to handle this.You can just see if it works on that breaker and if doesnt then just change the gauge and up the breaker to 35amps. Also the outlet is rated and you need to know that.I thought Iwasnt on the master electricians forum but a geneal workshop one?
Its all obvious thats its dangerous if you dont know what your doing. So isnt woodworking. I've learned that. I know not to touch the hot wire and have the power off and whats hot and what not and where ground go etc.
Thanks again, just getting fed up with all the sarcasm about electrical questions/answers.
I dont need anymore help.I use this forum to advise with no criticsm and learn as well.Theres a bundle of knowledge on here that we all could learn from.
Thanks for who have helped and didnt get fed up or made sarcastic remarks. When someone is just trying to learn.

I am no electrician and no expert, but I have read much of the NEC and other derivative manuals, as well as consulting with my brother whose knowledge far exceeds mine. I regularly read 5 - 6 ww forums on a regular basis, but rarely if ever follow electrical advice found there.

My post wasn't intended to be sarcastic. Electrical is NOT simple, at least as simple as many think. There are many factors you must consider- here are just some off the top of my head:

Circuit voltage
Equipment current demand and type (resistive, reactive)
Distance from panel (affects resistance and hence current)
Wire type and jacket (NM, BX, THNN, etc.)
Breaker type (std, quick trip, slow trip, GFCI, AFCI)
Receptacle (voltage, current, pin config, grounded, grounded w/neutral (4 prong), twist lock, etc.
NEC prohibits plugs and requires some high current equip to be hard-wired
Type of box- metal, plastic, etc.
Size of receptacle box- Box size (depth) is based on # and gauge of connections/conductors as defined in NEC
Method of grounding metal box- pigtail is now code in most areas.

Multiple outlets- method of daisy-chaining- many (most?) local codes require pigtails and do not allow receptacle to feed next outlet, except for receptacle down-stream from a GFCI.

These are just the ones that immediately come to mind.

There is a big difference between what may work, what is safe, and what is legal (and what your insurance company will pay if you screw it up and cause a fire)- just look at the size of the NEC book! The bottom line is unless the poster IS an electrician, and that is no guarantee, because he is basing his advice on your description of your setup, often the advice you get on these forums is worth exactly what you pay for it and in some cases is downright dangerous. There are just too many gotcha's to take it lightly and to believe everything you read- just look at the differences of opinion in this short thread. Honestly, some of the absolute worst advice I have ever seen on woodworking forums has come from electrical threads.

[Craig D Peltier]

I am no electrician and no expert, but I have read much of the NEC and other derivative manuals, as well as consulting with my brother whose knowledge far exceeds mine. I regularly read 5 - 6 ww forums on a regular basis, but rarely if ever follow electrical advice found there.

My post wasn't intended to be sarcastic. Electrical is NOT simple, at least as simple as many think. There are many factors you must consider- here are just some off the top of my head:


Circuit voltage


Equipment current demand and type (resistive, reactive)


Distance from panel (affects resistance and hence current)


Wire type and jacket (NM, BX, THNN, etc.)


Breaker type (std, quick trip, slow trip, GFCI, AFCI)


Receptacle (voltage, current, pin config, grounded, grounded w/neutral (4 prong), twist lock, etc.


NEC prohibits plugs and requires some high current equip to be hard-wired


Type of box- metal, plastic, etc.


Size of receptacle box- Box size (depth) is based on # and gauge of connections/conductors as defined in NEC


Method of grounding metal box- pigtail is now code in most areas.


Multiple outlets- method of daisy-chaining- many (most?) local codes require pigtails and do not allow receptacle to feed next outlet, except for receptacle down-stream from a GFCI.

These are just the ones that immediately come to mind.

There is a big difference between what may work, what is safe, and what is legal (and what your insurance company will pay if you screw it up and cause a fire)- just look at the size of the NEC book! The bottom line is unless the poster IS an electrician, and that is no guarantee, because he is basing his advice on your description of your setup, often the advice you get on these forums is worth exactly what you pay for it and in some cases is downright dangerous. There are just too many gotcha's to take it lightly and to believe everything you read- just look at the differences of opinion in this short thread. Honestly, some of the absolute worst advice I have ever seen on woodworking forums has come from electrical threads.
Agreed Allan , there is alot to learn.

[Roger Frazee]

Well you get between a rock and a hard spot with the electrical codes doing what you are asking. Frankly I don't see a problem with doing this with the table saw assuming it has internal overload protection and does not require a fused disconnect. 3 hp flC would not be over 17 amps at 230 volts so you would need 10 awg minimum for it if you apply motor rules and use romex (nm-b). Using motor rules and 8 awg romex with 35 amp breaker would be fine. Changing the plug on the table saw is no issue since a 6-50P is rated higher amperage than the required one for the table saw. This is done quite often though re purpose of a tools power cord plug is frowned on by some people.
The resistance heater is a bit difficult to treat as a motor operated piece of equipment. Personally I would not use it on the same branch circuit. I'd run a dedicated circuit for the heater. If you can you might post the specifications of the coil heater and we will look it over to see what options we may have.

We also need to make sure the branch circuit you have that is existing is right for the heater. If so you would just run another circuit for the cord and plug table saw and sander.

Your going to need enough spaces in your panel for the breakers so check that out.

Another option is a feeder that will carry the load of both the table saw and sander. This will allow you to run both or have both plugged in all the time not having to change back and forth. You will have two fused disconnects on the wall for each tool and two receptacles matched to the factory power cord plugs of each tool. Each disconnect will be fused or circuit breaker protected for the individual tool. Then the branch circuit conductors going from the protecting disconnect to the power tool or to a receptacle if cord and plug will be sized to the amperage requirements of the tool. So in your case with cord and plug 10 awg romex for the saw to its receptacle from its fused disconnect and 8 awg romex to the sander receptacle from its fused disconnect. It will look like this line diagram ...

[Dave Beauchesne]

Craig:

There has been some good info passed on, but, as an HVAC kinda guy, there is info on the nameplate that will steer you in the right direction.

In your case, you have a FLA ( full load amperage ) of 32 amps. OK.
In Canada, appliances have, on the namplate, a MINIMUM CIRCUT AMPACITY, ( which is a percentage, or multiplier of the FLA, often 1.25 ) and a MAXIMUM OVERCURRENT PROTECTION value ( usually 1.5 - 1.6 times the FLA, but not always ). So, if your NAMEPLATE says you should have a MINIMUM CIRCUT AMPACITY of 40, and a MAXIMUM OVERCURRENT PROTECTION of 50, those are your two options, nothing else.

Does it have that info on the nameplate?? Almost all inductive load appliances do.

Then, using that info, you have a 50 amp breaker on your sander that is withing the nameplate info ( for instance ). So you swap appliances to a 220v cabinet saw that has a nameplate stating the MAXIMUM OVERCURRENT PROTECTION shall be 30 amps.

There is the rub - you stall or overwork the saw badly, and poof, you let the smoke out of the motor - why?? - because the breaker is doing what it is supposed to, and the saw is not rated that high.

Yes, electrical is simple, but it is very easy to assume things that you don't understand. Guys are quick to be helpful and chime in with info that has worked for them - fair enough. But it may not always be correct. If the nameplate values are adhered to, and the wiring FROM THE BREAKER TO THE RECEPTICLE / APPLIANCE ARE SIZED PROPERLY, there will be lots less chance for a problem. One thing that is often overlooked is the fact that if wiring is done incorrectly, and there is a fire, the big bad insurance company will rub their hands with glee if they have an ' out ' .

PLEASE CHECK THE NAMEPLATE!!

JMH ( and experienced )O

Dave Beauchesne

[Roger Frazee]

In the USA the only appliances that list on nameplates minimum circuit ampacity and maximum circuit breaker are refrigeration and air conditioning equipment.

Woodworking equipment electrical connections are governed by what is listed in the manufacturers instructions.
Those not being available we use the motor rules of NEC article 430 or 440 depending on the type of equipment and motor.

The instructions from grizzly require a 35 amp breaker, if he uses cable like nm-b (your nmd) he needs 8 awg copper that carries 40 amp rating.

The table saw nameplate will not list a minimum circuit ampacity nor a maximum breaker. The motor name plate will show fla or horse power or it may show both specifications. Not having that information the motor is 3 hp. 230 volts ... the nec motor tables show the flc for a 230 volt 3 hp motor to be 17 amps. Following those motor rules requires the minumum circuit to carry approx. 22 amps. If we use nm-b cable we need 10 awg rated 30 amps 60C. We can have a max breaker 2.5 times the table flc or 2.5 times the namepalte fla if both hp and fla are stated on the nameplate and it is a listed motor appliance. However it is rare to have to use the max breaker calculated using the motor rules it is better to start with the mimum circuit breaker for the load served and see if the motor will start with out nuisance tripping. The jet table saw is 3 hp the grizzly sander is 5 hp.

Both will safely operate on a 35 amp branch circuit.

The jet table saw has overload protection at the motor on off magnetic switch and the grizzly sander has an overload protection block and contactor.

The breaker in the panel protects the wires in the supply circuit from overheating and overcurrent from short circuit or ground fault.

Both units will shut down from overload due to factory overload protection at the machine. The breaker will not enter into the overload picture for the power tool. If you stall the motor it will pull locked rotor amps and trip the circuit breaker before the wire overheats or if you are reaching overload limits for the motor a stall may trip the factory thermal overload of the machine before the circuit breaker.

Your insurance will pay a claim whether your fault or someone elses....:)



.

[Dave Beauchesne]

In the USA the only appliances that list on nameplates minimum circuit ampacity and maximum circuit breaker are refrigeration and air conditioning equipment.


Woodworking equipment electrical connections are governed by what is listed in the manufacturers instructions.
Those not being available we use the motor rules of NEC article 430 or 440 depending on the type of equipment and motor.

The instructions from grizzly require a 35 amp breaker, if he uses cable like nm-b (your nmd) he needs 8 awg copper that carries 40 amp rating.

The table saw nameplate will not list a minimum circuit ampacity nor a maximum breaker. The motor name plate will show fla or horse power or it may show both specifications. Not having that information the motor is 3 hp. 230 volts ... the nec motor tables show the flc for a 230 volt 3 hp motor to be 17 amps. Following those motor rules requires the minumum circuit to carry approx. 22 amps. If we use nm-b cable we need 10 awg rated 30 amps 60C. We can have a max breaker 2.5 times the table flc or 2.5 times the namepalte fla if both hp and fla are stated on the nameplate and it is a listed motor appliance. However it is rare to have to use the max breaker calculated using the motor rules it is better to start with the mimum circuit breaker for the load served and see if the motor will start with out nuisance tripping. The jet table saw is 3 hp the grizzly sander is 5 hp.

Both will safely operate on a 35 amp branch circuit.


The jet table saw has overload protection at the motor on off magnetic switch and the grizzly sander has an overload protection block and contactor.

The breaker in the panel protects the wires in the supply circuit from overheating and overcurrent from short circuit or ground fault.

Both units will shut down from overload due to factory overload protection at the machine. The breaker will not enter into the overload picture for the power tool. If you stall the motor it will pull locked rotor amps and trip the circuit breaker before the wire overheats or if you are reaching overload limits for the motor a stall may trip the factory thermal overload of the machine before the circuit breaker.


Your insurance will pay a claim whether your fault or someone elses....:)





.
Thanks for that Roger - I am pretty sure that CSA compliant equipment has different guidelines on other equipment.

Roger, I understand that in this case, there are mag starters / O/L protection blocks. Working with that type of protection on a daily basis, I have much more faith in it than ' internal thermal overload ' protection that is present in many motors that are used in woodworking equipment. I have seen several over the years on both HVAC and some WW equipment that failed to trip ( tablesaws and air compressors recently ) that actually had got so hot the paint was badly scorched and the windings were black.

I apologize for blurring the lines between Canada and the USA. From our local paper just today, there is a ' public service ' note from the Provincial Government - the ' Safety Authority ' states that ' If you plan to do your own electrical work on your residence, a BCSA Homeowner permit is required ' after which, it will be inspected by the Electrical Inspector.
While it maybe seems a bit harsh, it is designed to protect the homeowner.

My point was that while you may have a 220 v outlet, it does not mean you can plug just any 220 v appliance into it. That thought seems prevelant in posts of this sort. We are now able to DIY nearly anything due to big box and e-bay - that does not mean it is done properly in some cases. Thanks again for your input.

Dave Beauchesne

[Craig D Peltier]

Thanks for all the info again. It is much more complicated in the rules than I thought.
I am out of spaces on my breaker box. I was told that the 110 volt breakers can go to 1/2 spaces in the box with two small throw switches and then add another half for another outlet. Im not sure if the 220 can be done in just one whole space verse tow though.Just to free up some space. I do have a 50amp going to dryer but mine runs on gas. I could always have it disconnected and reconnected when we moved.
Nevertheless, im going to get someone in here that knows so I dont roast a motor or start a fire and have the box changed around a bit to help me in my needs.

[Alan Schaffter]

Thanks for all the info again. It is much more complicated in the rules than I thought.
I am out of spaces on my breaker box. I was told that the 110 volt breakers can go to 1/2 spaces in the box with two small throw switches and then add another half for another outlet. Im not sure if the 220 can be done in just one whole space verse tow though.Just to free up some space. I do have a 50amp going to dryer but mine runs on gas. I could always have it disconnected and reconnected when we moved.
Nevertheless, im going to get someone in here that knows so I dont roast a motor or start a fire and have the box changed around a bit to help me in my needs.

Good decision.

Excellent idea also to re-purpose that dryer breaker and/or circuit. If you want to run a lower amp circuit to save money and avoid having to wire stiff and expensive #6 NMB, you can put in a smaller breaker (just can't go the other way without going with bigger wire.)

Roger has good info above. One thing he might want to expand on/clarify is his statement:

"We can have a max breaker 2.5 times the table flc or 2.5 times the namepalte fla if both hp and fla are stated on the nameplate and it is a listed motor appliance."

That only deals with the motor and the breaker- max allowable to protect the motor. If you have a breaker that can handle 2.5X the FLA, the wiring must be able to carry that load as well.

[Tom Veatch]

...
My point was that while you may have a 220 v outlet, it does not mean you can plug just any 220 v appliance into it. ...

Interesting!

No intent to be contentious, but for my own edification, assuming I have a properly configured 240v/30amp circuit, can you give some examples of loads requiring less than 30 amps that cannot be plugged into that circuit. Also assuming the plugs are compatible with the receptacles.

[Roger Frazee]

Good decision.

Excellent idea also to re-purpose that dryer breaker and/or circuit. If you want to run a lower amp circuit to save money and avoid having to wire stiff and expensive #6 NMB, you can put in a smaller breaker (just can't go the other way without going with bigger wire.)

Roger has good info above. One thing he might want to expand on/clarify is his statement:

"We can have a max breaker 2.5 times the table flc or 2.5 times the nameplate fla if both hp and fla are stated on the nameplate and it is a listed motor appliance."

That only deals with the motor and the breaker- max allowable to protect the motor. If you have a breaker that can handle 2.5X the FLA, the wiring must be able to carry that load as well.

Your correct Alan I should clarify. The wiring doesn't have to be sized to carry 2.5 times or the max. breaker amperage. They only need to be sized 1.25 times the fla ... if the motor is a listed appliance with fla and horsepower on the nameplate. If not both listed then 1.25 times the NEC table flc. In almost all residential/commercial cases with wood working tools/machines a motor nameplate will list both specifications but not always. If no manufacturers instructions/specifications then we use NEC table 430.248 for single phase motors to cross reference horsepower to a full load current. This will be a worse case figure. So for example if a 3hp motor single phase 230 volt the table shows 17 amps flc. The branch circuit conductors must be sized to 1.25 times that for a single motor circuit or 21.25 amps. This requires a 12 awg copper conductor if using nm-b or thhn which is rated 25 amps. To size the inverse time breaker you are allowed to increase it 2.5 times the table flc so the breaker could be as much as 45 amps on 12 awg in the case of a 3 hp single phase motor. This is to insure that the motor can start during starting inrush current levels (close to locked rotor) without tripping. This lasts very briefly less than a couple seconds then the motor runs at rated no load current. So the wire ampacity only needs to satisfy the rated load current (fla) of the motor x 1.25. It is better in most applications where a static load is not present at start up ...for example a loaded conveyor belt .. to just use a breaker that meets the minimum requirements of the motor if starting under a no load application.

A good tutorial is here if the article doesn't show and you get the ECM login page simply do the log in (it's free) and the view the tutorial/article. This is the best one I have found for reference when subjects like we have here come up.

http://ecmweb.com/mag/electric_motor_calculations_part/?smte=wl

A brief explanation is here

http://www.cooperbussmann.com/pdf/31526743-b7e0-4732-858c-ca2a537c2201.pdf

Also some calculation examples are here ... you can see in the first example using motor rules you can have a 60 amp breaker on 10 awg.

http://www.mikeholt.com/mojonewsarchive/NEC-HTML/HTML/Article-430-Motors-Motor-Circuits-and-Controllers~20031126.htm (http://www.mikeholt.com/mojonewsarchive/NEC-HTML/HTML/Article-430-Motors-Motor-Circuits-and-Controllers%7E20031126.htm)


It is a little hard to get your head around but in most cases where motor rules are strictly followed is commercial or industrial applications where the motors that are not part of appliances.

In the case of most woodworking equipment for a home shop or commercial shop when you do not have manufacturers instructions or can't get them you would use NEC motor rules,the NEC tables along with the motor nameplate but it will be rare to apply the maximum 250% breaker to the circuit. IMO you would want to increase the conductor size by a factor of 1.25 x the nameplate fla if hp and fla are listed in accordance with the motor rules of article 430... if not use the flc of the motor tables for the hp of the motor.

Then start with a breaker that matches the calculated branch circuit size. For example if I had a 3 hp motor and it was a table saw and no instructions and the motor nameplate listed fla and hp and the fla was listed at 15 amps. I'd use 1.25 x 15 = 18.75 amps. I could use a 14 awg conductor as a minimum rated 20 amps 60C column of table 310.16. For motors I am released from the 15 amp breaker requirement of general purpose branch circuits for 14 awg and can install up to a 2.5 x 15 = 37.5 amps .. next size up is a 40 amp inverse time breaker.. so 40 amp breaker on 14 awg. Yeah that is a little hard to understand at first. In this example I would use a 20 amp breaker not the maximum 40 amp one if I was running the branch circuit for a table saw or drill press etc. So 20 amp breaker on 14 awg for a 3 hp motor with 15 amp fla.

This will almost always be all that is required to start a woodshop machine like a table saw motor. Other applications might require you to increase the breaker according to the motor rules to get the motor to start without tripping the circuit breaker. Air compressors often fall into this catagory.


So in this case that Craig has using motor rules would allow both table saw and sander to operate on a circuit sized for the grizzly sander using the 35 amp breaker and 8 awg romex. It would of course be prudent to check the motor nameplate of the table saw (Dave mentioned this) to be sure a 35 amp breaker does not exceed what is allowed using motor rules

One thing to keep in mind in all this is it is best to follow manufacturers instructions and have dedicated circuits to both the saw and sander. We can't always do that ... so using motor rules for woodworking equipment and a little common sense will keep you out of trouble.

[Gerry Grzadzinski]

If 30 amps is the max current draw, from my experience with wide belt sanders, you probably won't get anywhere near that, unless the starting load is very high.Last job I worked at, the sander had an ammeter on it, and even with fairly heavy passes, the current draw didn't go up that much.

I just scanned through this, so sorry if it's already been mentioned.

[Roger Frazee]

Craig

I see I made an error in earlier posts about 22 amps needing 10 awg minimum if using nm-b (romex). That should be 12 awg not 10. 12 awg is rated 25 amps in the 60C column of table 310.16. Sorry for my mistake. I have a later post in reply to Alan Schaffter that corrects the earlier examples.

[Craig D Peltier]

If 30 amps is the max current draw, from my experience with wide belt sanders, you probably won't get anywhere near that, unless the starting load is very high.Last job I worked at, the sander had an ammeter on it, and even with fairly heavy passes, the current draw didn't go up that much.

I just scanned through this, so sorry if it's already been mentioned.

When the G9983 Grizzly sander starts the amp meter bumps up to 30 for a nanosecond.

[Rod Sheridan]

Interesting!

No intent to be contentious, but for my own edification, assuming I have a properly configured 240v/30amp circuit, can you give some examples of loads requiring less than 30 amps that cannot be plugged into that circuit. Also assuming the plugs are compatible with the receptacles.


Hi Tom, I have a Hammer A3-31 jointer planer.

Maximum overcurrent protection allowed is 16 amperes, so it cannot be plugged into a 30 ampere receptacle.

regards, Rod.

[Charlie Knauer]

Craig

I see I made an error in earlier posts about 22 amps needing 10 awg minimum if using nm-b (romex). That should be 12 awg not 10. 12 awg is rated 25 amps in the 60C column of table 310.16. Sorry for my mistake. I have a later post in reply to Alan Schaffter that corrects the earlier examples.

The correct wire size for a 22amp load is #10. The 25 amp rating is for derating purposes only.

Charlie

[Rob Russell]

Craig

I see I made an error in earlier posts about 22 amps needing 10 awg minimum if using nm-b (romex). That should be 12 awg not 10. 12 awg is rated 25 amps in the 60C column of table 310.16. Sorry for my mistake. I have a later post in reply to Alan Schaffter that corrects the earlier examples.

That's true if it's THHN/THWN in conduit. If the circuit is wired with NM-cable (aka "Romex"), #12 is only good for 20 amps.

[Charlie Knauer]

That's true if it's THHN/THWN in conduit. If the circuit is wired with NM-cable (aka "Romex"), #12 is only good for 20 amps.

How did you come up with that. 310.16 shows #12 with an *. At the bottom of the page * tells you 240.4d.
240.4d states;
Small conductors. Unless specifically permitted in 240.4e or g, the overcurrent protection shall not exceed that required by (D)(1) through (D)(7) after any correction factors for ambient temperature and number of conductors have been applied.
(D)(5) 12 AWG Copper 20 amps.

Charlie

[Roger Frazee]

The correct wire size for a 22amp load is #10. The 25 amp rating is for derating purposes only.
That's true if it's THHN/THWN in conduit. If the circuit is wired with NM-cable (aka "Romex"), #12 is only good for 20 amps. Charlie and Rob please follow along with me as I have not looked back at the forum for several days. The underlined and bold is mine.


The ampacity of NM-b cable is ruled by NEC 334.80.

" The ampacity of nm,nmc,nms cable shall be determined in accordance with the 60C (140F) conductor temperature rating....the 90C (194F) rating shall be used for ampacity derating purposes, provided the final derating does not exceed that for a 60C rated wire.

The ampacity of 12 awg Nm cable at 60C = 25 AMPS TABLE 310.16

The ampacity of 12 awg at 90C for derating purposes is 30 amps

There is an asteric next to the 12 awg ... Looking at the footnotes the asteric means to see 240.4D

240.4(D) Small conductors. Unless specifically permitted in 240.4(E) or (G) the overcurrent protection shall not exceed that required by (D)(1) through (D7) after any corrections factors for ambient temperature or number of conductors has been applied.

Overcurrent protection for 12 awg is not to exceed 20 amps 240.4(D)(5).

This has nothing to do with the ampacity of the wire.

12 awg is rated 25 amps whether nm or thhn or thwn. Further .. deration is taken from the 90C column which is 30 amps not 25 amps. NM is a 90C rated insulation....;)

Now how do we get to have a larger breaker than 20 amps for 12 awg nm or thwn or whatever as specified by 240.4(D) for small conductors?

Please refer to 240.4(G)

"Over current protection for specific conductors shall be permitted to be provided as referenced in table 240.4(G)

It then shows you that breaker protection is amended for motor appliances and motors in accordance with art.422 and 430 among others.

So a 22 amp load can be served for a motor with #12 nm cable (25 amps) as a minimum and not required to be #10 awg . I then am allowed to breaker that nm #12 awg in accordance with table 430.52. This releases me from 240.4(D)(5) limiting me to 20 amp OCPD for #12 awg.

In contrast I am not allowed any amendment to overcurrent protection for 12 awg used for a general purpose branch circuit that can have multiple receptacles.... Only motor circuits or those specified in table 240.4(G). The ampacity of 12 awg is still 25 amps but I cannot use a breaker protecting it that is over 20 amps for anything unless listed in table 240.4(G). This will not work for the motor tools we are discussing in this thread unless we run a individual circuit to a single receptacle serving only these tools.

[Roger Frazee]

When the G9983 Grizzly sander starts the amp meter bumps up to 30 for a nanosecond.

Yep so you should be fine doing as we have been discussing.