New Bandsaw

[robert391]

My new Laguna 14 SUV band saw was delivered on Thursday afternoon. After along search thru dealers and websites I finally decided on Laguna. Ordered it thru Rockler 10% off with mobility kit, 1" re saw blade, 1/2". Delivery was perfect, after dropping it off with the tailgate service he used the dolly to place it in my shop.
I was out there early this morning putting it together using wood blocks and jigs to install motor and the table which was a challenge for one person. This band saw call for 30 amp and was prewired with no twist lock. I called Laguna yesterday and says to go and use the plug with 30 amp or if you are not comfortable cut the cord and place twist lock. I'm not going to do any more today, still have to place the blade on and will post photos later.

 

[ehpoole]

Just an FYI,

I've moved this thread to the "General Woodworking" forum as it is not an appropriate thread for the "Help Desk" forum.

Otherwise, congratulations on the new bandsaw, I'm sure you'll get many years of joy from your purchase!

 

[FredP]

Do you need a twist lock plug? I have several available.

 

[robert391]

Thanks Fred, but I'm going to talk to a electrician first and see if I can use the cord supplied, but if not I'm interested.

 

[McRabbet]

To insure secure connections, I use L6-20R/L6-20P and L6-30R/L6-30P three-wire twist lock Receptacles/Plugs for my 20 Amp or 30 Amp 240 volt corded tool hookups (Table saw, jointer and drum sander). My only hardwired unit is my 5 HP ClearVue Cyclone which has its own disconnect on a 30 Amp circuit.

 

[Bob Carreiro]

Wow... great tool! Congrats!

 

[tarheelz]

Very very very nice. <Insert drool>

I thought it interesting that Rockler says it "requires" 220 with a 20 amp breaker but that a 30 amp breaker is recommended.

What sort of amperage does it draw on start up? Must be well over 16 amps.

The trick is that if you put a 30 amp breaker on your existing 220 circuit and you don't have 10 gauge wire in the wall you've created a code violation (even though so long as you only have your Laguna hooked up, there's no actual danger).

Edit: Laguna's manual "requires" a 30 amp breaker. It's a Rockler thing that you can use a 20. Nevermind.

 

[Bill Clemmons]

Congratulations Robert. Hope you enjoy the saw for many years to come.

 

[Matt Furjanic]

I have two 20A breakers and 12 gauge wire on my circuit, and have been running my SUV on it for about a year and a half with no problems.

 

[ehpoole]

I have two 20A breakers and 12 gauge wire on my circuit, and have been running my SUV on it for about a year and a half with no problems.

You're likely misunderstanding the OP's situation. All 240V circuits use a pair of circuit breakers -- "two" 20A (a double-pole) circuit breakers feeding #12AWG copper are well within code -- as they would be if they were up to 25A (for direct wired appliances, 20A for receptacle circuits). However, feeding #12AWG copper with a 30A circuit breaker (particularly for a receptacle circuit) would be a code violation as it exceeds the maximum allowable rating for a #12AWG copper conductor (which is 25A at 240V or 20A at 120V).

The minimum allowable conductor size for a 30A circuit would be #10AWG copper.

However, if this bandsaw's motor is 3HP or less then the OP should be able to get away with running it on a 20A circuit (using 20A receptacle and plug) just fine -- you would really have to overload the motor to exceed 20A running. However, if the motor is larger than 3HP (e.g. 4 or 5HP) then the OP will indeed require a 30A circuit breaker for his bandsaw. If the existing wiring is #12AWG copper, then I would opt for trying it out with a 20A circuit breaker (plus 20A rated receptacle and plug) to see if you really need a 30A breaker before upgrading the wiring and circuit breaker -- but I seriously doubt that you will find the 30A circuit breaker to be necessary.

 

[LeftyTom]

Robert SCORES with time to spare! :icon_thum

 

[Jeremy Scuteri]

.... exceeds the maximum allowable rating for a #12AWG copper conductor (which is 25A at 240V or 20A at 120V).....

Any idea why the max current for #12AWG copper conductor depends on the line voltage? My simplistic view has always been that the line voltage dictates the insulator needed around the wire and current dictates how thick the copper conductor needs to be. I don't see any reason why running at 240v increases the current carrying capability of the wire. Just curious more than anything. I am an electrical engineer but my expertise is in transistors, not motors and wiring.

 

[cpowell]

Any idea why the max current for #12AWG copper conductor depends on the line voltage? My simplistic view has always been that the line voltage dictates the insulator needed around the wire and current dictates how thick the copper conductor needs to be. I don't see any reason why running at 240v increases the current carrying capability of the wire. Just curious more than anything. I am an electrical engineer but my expertise is in transistors, not motors and wiring.

Not familiar with 240 vs 120V ratings on small conductors. I generally start with standard ampacity tables and check for ambient temperature, line loss, and number of conductors in a raceway. (BTW as an EE I don't care for the term "ampacity")

My experience is in industry applications typically for distribution or motor loads. I size conductors per NEC/company engineering guidelines.

My "shoot from the hip" to the OP would be:
10AWG wire on 30A breaker
12AWG wire on 20A breaker
I have found OEM providers use small conductor sizes on the pigtails they provide. Can be a challenge using oversized twist-loc connectors.

And I agree 20A is normally just fine for "3HP" woodworking machine motors with short accel times.

 

[ehpoole]

Any idea why the max current for #12AWG copper conductor depends on the line voltage? My simplistic view has always been that the line voltage dictates the insulator needed around the wire and current dictates how thick the copper conductor needs to be. I don't see any reason why running at 240v increases the current carrying capability of the wire. Just curious more than anything. I am an electrical engineer but my expertise is in transistors, not motors and wiring.

It comes down to an interaction between two basic formulas that will be very familiar to anyone with an electronics background: V=IR (Voltage Drop) and P=I^2R (Heating of the wire due to voltage drop). In the NEC Code these are the two factors that must be considered in conductor sizing as you are typically allowed a 5% voltage drop in a conductor (i.e. 6V at 120V, 12V at 240V) BUT you must also ensure that the conductor, at maximum rated load, will never be heated to a level that exceeds its insulation rating (e.g. typically 60C, 85C, 105C, etc.) -- this temperature rating must also consider maximum possible ambient temperatures as well as other nearby conductors that may contribute to heating, etc., so the NEC "rule of thumb" numbers tend to be fairly conservative.

However, about the only time you get to exploit that 25A exception for 240V is for direct hard-wired appliances since you'll typically strike out if you try hunting for 25A plugs and receptacles (and you can not use 20A or 30A receptacles on a 25A circuit).

 

[Jeremy Scuteri]

Thanks Ethan. So, I guess the assumption here is that 20A through a #12AWG wire at 120v is limited by the 5% IR drop and 25A through the same wire at 240v is limited by the power dissipated in the wire (heat). Obviously there is some implied assumption on the length of the wire that doesn't seem to be stated.

I have the same issue with power tool manuals that state the required AWG of an extension chord based on length from the receptacle. Nowhere does it account for how close the receptacle is to the breaker box. I guess these guidelines assume the worst case scenario.

 

[Mike Davis]

Matt said he has the same saw running on 20 amp 220 breakers with 12 AWG wire for over a year with no problems.

i trust him and would do the same as he has done.

 

[robert391]

Thanks guys,. you all have been helpful, I finished putting the band saw together yesterday except for installing the re-saw blade. When I built the shop I installed two 10 gauge outlets for future use so now I'm going to get an electrician to install the proper outlet receptacles for the band saw.

 

[Kicbak]

I got a Laguna 14 SUV a few months ago. When I had the 220 installed, my electrician asked what I was planning to run and he said 20 amp breaker and 12 AWG wire would be enough. I went with his recommendation and I've not had an issue either.

 

[robert391]

Thanks again guys for your suggestions. I installed the 20 amp double pole breaker and is up and running. Now to start sawing up some of that wood.

 

[Hmerkle]

Thanks again guys for your suggestions. I installed the 20 amp double pole breaker and is up and running. Now to start sawing up some of that wood.

We don't believe you - there are still pictures in my head of a crated bandsaw!