Power cord size for 5hp table Saw?

[Travis Conner]

Bought a delta x5 unisaw 5hp. Motor says 20amps on the tag. Looks like it came from the factory with a short 12 gauge cord. Thought that was a little odd. Maybe the same cord is used for the 3hp motors? Anyways, I went out and bought 25ft of 10 gauge wire to lengthen it since it was only like 4ft long and hooked it to a 30 amp breaker since that's what the general consensus seems to be. I suppose the 12 gauge cord would have been fine since it wouldn't be pulling 20 amps all the time. Opinions?

[michael dilday]

I am assuming it is 220 volts. Looking on the Home Depot website for the attached link it shows 15 amps for a 5 hp @ 220 volts. I am not sure about your specific saw. It should show in the manual what breaker is needed and what extension cord should be used. In any event I would make sure that the breaker is not larger than the cord and equipment can handle. I am not an electrician but you don't want the weakest link to be the cord.

https://www.homedepot.com/p/Delta-5-HP-Motor-10-in-Unisaw-with-52-in-Biesemeyer-Fence-System-36-L552/205112176

[Travis Conner]

Mine said the same thing. Then I looked at the data plate on the motor and it says 20.

[Travis Conner]

20 amps is borderline for the 20 amp breaker. 10 guage cord is rated at 30 amps.

[michael dilday]

Assuming I am looking at the same Delta 5 hp saw the specs say 15 amps. 20 amps is probably startup amps and 15 is probably running amps. Just a hunch.

[Travis Conner]

I have a 5hp planer and it calls for a 30 amp breaker. What's the difference? I didn't want to take a chance on popping breakers.

[George Makra]

Breakaway amps for any motor is 7 times FLA which stands for Full Load Amps.

And a ten gauge cord on a 30 amp breaker is what I would use.

[michael dilday]

This is what the manual says for a 36-L336, 36-L352, 36-L552 or 36-L552LVC.

FOR FIVE HORSEPOWER, SINGLE PHASE UNITS
The circuit should not be less than #10 wire and should be protected with a 40 Amp time delay fuse.

[mike waters]

I'd just a call a licensed and bonded electrician. Pay him $100 to come out and make sure everything is squared away. That way there is no missed sleep over it all. That's what I did for my 7.5hp!

[Rod Sheridan]

Flexible cord has different ampacity than permanent wiring.

With only 2 current carrying conductors the rated ampacity would be 25 amperes......Rod

[Travis Conner]

Oh I forgot about that. Doesn't really matter, that 10 gauge cord can be taken off and used for something else one day if needed. Better to over do it than to just barely do it is my saying. The cord will still work fine.

[Travis Conner]

Can't find many electricians in my area that will come out for $100 Or even $1000. They're cocky in my area.

[michael dilday]

Oh I forgot about that. Doesn't really matter, that 10 gauge cord can be taken off and used for something else one day if needed. Better to over do it than to just barely do it is my saying. The cord will still work fine.

The manual for the saw covers extensions cord sizing also.

[Charlie Velasquez]

Flexible cord has different ampacity than permanent wiring.

With only 2 current carrying conductors the rated ampacity would be 25 amperes......Rod

Rod, that 25 amp rating, ... is that for the 12g or the 10g?

[Travis Conner]

12 guage. He said it depends on the wire. Building wire is different than portable SOO and SJ wire. I was sitting there wondering why the factory wire coming out of the motor was only 12 guage. Well rod answered the question.

[David L Morse]

At the risk of piling on with too much information, here's the applicable NEC table:

425976

[Travis Conner]

The manual is misleading it says the 5hp saw should be hard wired to the wall and now cord used. Well that may be fine and dandy if it's in a huge shop where it can stay in the same place for the next 20 years, not all of us have that luxury. You have to remember manuals are written by the lawyers.

[Alex Zeller]

Power cords are always hard. Wiring in a wall always assumes it could see 100% use at maximum rated current. For a cord it's different. You're 5hp table saw isn't going to be drawing the maximum current all the time it's running. It'll have a surge when first turned on and then the draw will be much less. Even if you were to make the most demanding cut, unless you and 10,000 bft of lumber you were going to feed into the saw nonstop, it's not going to last very long. That's why an engineer may put a 14 awg cord on a piece of equipment that has a max load of 20 or even 25 amps. That being said I just use the standard wiring chart based on the FLA of the motor for a cord. You can always go a size bigger if the cord is getting hot (slightly warm isn't a problem) when being used.

[Travis Conner]

Wow it just sounds like a penny pinch kind of thing sonthats what I did.

[Andrew DiLorenzo]

Well, you have a good cord, don't worry about it and move on and enjoy your saw.

[Rod Sheridan]

Rod, that 25 amp rating, ... is that for the 12g or the 10g?

That’s for 12AWG......Flexible cord (cab tire) not building wire......Rod

[Mike Cutler]

You’re fine with the 10 awg. No worries. :)
I have a 5hp commercial washer on 10awg, SOOW extension cord. No way your saw will pull the amps that washer does going into the spin cycle with two horse blankets in it.;)
My 5hp air compressor is also on 10awg,SOOW cord.
The short length of 12awg is probably about as long as 12awg can be and still meet UL ratings.

[Tim Otto]

This is what the manual says for a 36-L336, 36-L352, 36-L552 or 36-L552LVC.

FOR FIVE HORSEPOWER, SINGLE PHASE UNITS
The circuit should not be less than #10 wire and should be protected with a 40 Amp time delay fuse.

he circuit breaker is there to protect the wire, not the motor. A #10 wire rated at 30A should be protected by a 30A circuit breaker.
T

[roger wiegand]

I'd just a call a licensed and bonded electrician. Pay him $100 to come out and make sure everything is squared away.

Where do you find an electrician to come to your house for $100?? It is to laugh, as the saying goes. Think more like $250-300 just to show up, lots more if they actually do something. And, at that, licensed doesn't necessarily get you competent. If you spend the time and effort to learn enough about it to know whether your electrician knows what s/he's doing you might as well do it yourself unless the law requires otherwise. Even in MA you don't need a license to put a power cord on an appliance (or table saw).

[Bruce Lowekamp]

At the risk of piling on with too much information, here's the applicable NEC table:



That's the right information :) The ratings we all know (20A=12ga, 30A=10ga) have to do with wire running at 100% current inside walls with insulation, etc. Don't cover your table saw cord with a foot of insulation. It will be fine.

Bruce

[Bill Dufour]

Insulation can include a foot of sawdust on the cord.
Bil lD.

[mike stenson]

Insulation can include a foot of sawdust on the cord.
Bil lD.

It's not a permanent installation. The list that David posted is correct.

[Mike Cutler]

That's the right information :) The ratings we all know (20A=12ga, 30A=10ga) have to do with wire running at 100% current inside walls with insulation, etc. Don't cover your table saw cord with a foot of insulation. It will be fine.

Bruce

Bruce
The ampacity ratings being referenced are for SO,SOOW,SJOW, flexible cord. #10, AWG, SO cord will carry 30 amps. If the cable is to long, there are charts for ampacity and voltage change over distance

From Southwire's website.
http://cord.southwire.com/docs/Cord_Spec_Sheets/Royal%20SOOW%20Bk%2018-10%20awg%20SPEC%2070000.pdf

[michael dilday]

he circuit breaker is there to protect the wire, not the motor. A #10 wire rated at 30A should be protected by a 30A circuit breaker.
T

I hear what you are saying Tim - I just copied right out of the manual.

[Rollie Meyers]

he circuit breaker is there to protect the wire, not the motor. A #10 wire rated at 30A should be protected by a 30A circuit breaker.
T


Motor rules are significantly different then for branch circuits, and you can have different wire wire and fuse/circuit breaker combos then what is allowed for a branch circuit, same thing also applies to air conditioning equipment, and welders.

With a 5 HP motor the circuit must be sized from NEC table 430.248 which lists a 5 HP 1Ø motor as 28A @ 230V and 125% of 28A is 35A so if Romex® is used it has to be 8AWG, if THHN is used 10 AWG is 35A (motor rules apply, not branch circuit) is fine. Even if a motor nameplate amperes is less then that NEC table it is still required to be sized from table 430.248.

[Travis Conner]

Like I said it's all about that money. Even the factory cord that's supposed to be plugged into the wall was only like 3ft long. No way you could plug it into the wall unless it's right next to it and even then you would be tripping over it.

[Tim Otto]

Motor rules are significantly different then for branch circuits, and you can have different wire wire and fuse/circuit breaker combos then what is allowed for a branch circuit, same thing also applies to air conditioning equipment, and welders.

With a 5 HP motor the circuit must be sized from NEC table 430.248 which lists a 5 HP 1Ø motor as 28A @ 230V and 125% of 28A is 35A so if Romex® is used it has to be 8AWG, if THHN is used 10 AWG is 35A (motor rules apply, not branch circuit) is fine. Even if a motor nameplate amperes is less then that NEC table it is still required to be sized from table 430.248.

It is a branch circuit as the tablesaw in question has a plug/chord and is considered an appliance. You are correct regarding NEC if the motor was hardwired as a motor circuit. However, as an appliance it is covered under UL...different rules. NEC Is not a design manual, it only sets the minimum standards for construction.

[Justin Rapp]

Can't find many electricians in my area that will come out for $100 Or even $1000. They're cocky in my area.


haha - my area is the same. Going rate for licensed trades is 150 or so per hour, usually minimum of 2 hours plus travel time. If you could even get them to come out to run 1 circuit.