# Sizing new power cord for Grizzly jointer



## moosie (Jun 14, 2017)

Hi,

I just received a Grizzly 0858 jointer. The power cord is about ten feet, and I want to replace it with a 20-25 footer. The unit is rated 12A @ 240V, and comes with a 14 gauge cord. I suspect I can get by with 14 gauge, but to be safe I plan to use 12-3.

I'm considering just getting a standard 120V cord and chopping the ends off. Wire direct into the machine, and fit a male 6-20 on the other end.

Is there any reason I shouldn't do that? All the regular 12-3 extension cords say rated for 125V on them, but is that relevant in this context?

Thanks.

By the way, real quick unboxing review of the jointer:

This unit comes all assembled, in a plywood crate. All I had to do was mount the control panel pole, which was folded down for transport. The hardest task was getting it off the pallet.

The preservative gunk on the cast iron came right off with a bit of naphtha on a shop towel. Then it got a light coating of Boeshield T-9.

Quality control was excellent on this beast. Table flatness and coplanarity are all within .001" overall.


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## moosie (Jun 14, 2017)

Follow up info:

I calculate wattage through my power cord to be 12A x 240V = 2880.

I'm looking at a typical 12-3 extension cord, and it says max is 125V @ 15A = 1875 watts.

https://www.homedepot.com/p/Duromax-XPC12025A-25-ft-12-3-Gauge-Single-Tap-Extension-Power-Cord-XPC12025A/302795695


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## bigblockyeti (Sep 9, 2013)

12-3 should be perfectly fine for what you're trying to do. If you look at the jacket on the cord, It'll likely say 250V or 600V max.


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## Delete (May 19, 2017)

If your going to a 25 ft. cord then definitely go with a 12-3 cord. The 125V at 15A designation is for a 125V circuit which has 1 hot and 1 neutral wire. For a 240V circuit you would have 2 hot wires which means your actually good for double the wattage 2(125V at 15A) = 3750 watts.


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## Smirak (Dec 24, 2016)

When I extended the power cord for my G0833P table saw, I went with 12-3…


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## BlueRidgeDog (Jan 2, 2019)

I always go up a size for stranded and make my cords out of #10, but 12/3 would easily handle it. 12 house wire would be code for 20a, 14 is approved for 15a.


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## clagwell (Dec 20, 2018)

The current and voltage ratings are for the extension cord in total, not the cable. The extension cord ratings are, in this case, determined by the connectors. The connectors are 5-15. That makes it a 125V 15A extension cord. The cable itself will be good for at least 300V 25A (cords have a higher current rating than Romex).

Btw, 12awg is overkill here, a 14awg cord is rated at 18A, and 25' will only drop about 1.5V at 12A. Your motor is likely rated for 230V operation which allows for 10V drop from a 240V supply.

Check the gland where the power cord enters the unit. Make sure it will take the larger cable if you choose that route.


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## SMP (Aug 29, 2018)

sometimes extension cords can be limited by the ratings of the plug(the least common denominator). I've had cheap extension cords where you plug something in and you see sparks and the arc literally fries the connectors.


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## Delete (May 19, 2017)

For long cords the issue is not so much current draw as long as it is below rated draw, but the heat build up in a long cord, the longer the cord the more resistance and the more heat generated in a 240V circuit with two hots double the heat generation. You can get away with it in a 6' cord, on a long extension cord it is always recommended you go a size larger, you will usually find this warning in the literature.


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## Delete (May 19, 2017)

SMP sounds like you tried to plug a 115V plug into a 240V or something like that. Your plug connectors are marked with there ratings and should match the circuits they are connected to.


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## clagwell (Dec 20, 2018)

> ...more heat generated in a 240V circuit with two hots double the heat generation…


Both 120V circuits and 240V circuits carry current on two wires. The current in the 240V circuit is half that of the 120V circuit. So if the same wire gauge is used the heat generated in the 240V wiring is one fourth that of the 120V circuit.



> For long cords the issue is not so much current draw as long as it is below rated draw, but the heat build up in a long cord, the longer the cord the more resistance and the more heat generated..


The heat generated per unit length doesn't vary with total length. The total heat generated is of course proportional to length. This only becomes a problem if a long piece of cord is coiled up in a pile and insulated.

For the OP's example, 14ga wire is .0026Ohm/foot. One foot of cord has two feet of wire so .0052Ohm. 12A squared is 144 so 144x.0052 = 0.75Watt/foot. For a 25' cable that's 19Watt for the whole cord, or 12Watt for 12ga wire.


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## moosie (Jun 14, 2017)

Thanks guys. The connectors determining the lower rating makes sense.

I hadn't thought about the 12-3 not fitting in the strain relief / hole. I guess if it won't fit, then I'll plug the existing cord into a 10-15 foot extension cord.

Grizzly doesn't mention lengthening the cable, but states a 12-3 extension cord is acceptable, 50 ft or less.

Either way I go, it seems I can just chop up a regular 12-3 125V extension cord.


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## Delete (May 19, 2017)

No argument with your theory here, it's your theory. Manufacturers recommendations stand out when ever I wire a machine, some of the heavier machines I have rebuilt came with heavier cable and they were on short cords, and I have always spent a little extra on wire to be safe rather than run close to the line. But thats my opinion.


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## DBDesigns (May 29, 2018)

FYI,
The way I approach my cords in the shop is to oversize them so I never have to worry about length. I always keep a few extra "power hoses" around in case I need to work far from the shop with a skill saw, chop saw, or compressor. Here's a hint; HD sells various gauges of stranded wire cords by the foot and connection ends in different current ratings. I always assemble my own cords so I can determine the capacity and it costs way less. As far as strain relief, I would just increase the size of the hole in the tool case and use a strain relief from the electrical section.


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## sgcz75b (Jan 21, 2019)

Recently bought a GO858 jointer. I needed it by a certain island wall where I didn't have a 220 outlet. Since I have several other 220 tools all using the identical plug I simply made a 16' 10 gauge 2 wire (with ground wire) extension cord. Ran it from an existing 220 receptacle up the wall, over, and down EMT to the work island where I secured it in a receptacle box.

Easy to do and you don't have to replace the jointer cord. Cost about 10 bucks for the 220 plug and receptacle as I already had plenty of 10 gauge wire, EMT, and receptacle box.

If it was me wanting a 25' 220 extension cord, I'd go with 10 gauge. You paid $1800.00 for the jointer. This isn't the time to count pennies for an extension cord.


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## ibewjon (Oct 2, 2010)

E (voltage) x I (current in amps ) = P (power in watts ). 1000 watts equals 1 kilowatt. If you double the voltage, current is reduced to half, and watts used is the same with either voltage. The cost savings with higher voltage comes from reduced wire and conduit size.
( Manufacturers can use smaller cord than code allows us to use. ) For a short cord, 12 is ok, but a heavier 10 awg cord is cheaper than a new motor.


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## BlueRidgeDog (Jan 2, 2019)

Lots of really great replies here including some very clear math as to what is happening. Personally I only use 10 awg for new cords or extensions on 240v equipment (stranded). Logically I can then use an extension then for any tool regardless of amperage or on my welder. When fitting a new cord, it is easy to just keep one wire size on hand.

"If" I needed 25' of wire for a device, I would probably install a new outlet closer to the device, though I may use an extension (I have a 25' one for this purpose) until I decided to roll up my sleeves and get to it. For all the reasons listed above, there is a reason equipment comes with cords of a specific length.


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## moosie (Jun 14, 2017)

I don't understand all the 10 AWG comments. Grizzly themselves state 12 gauge is fine up to 50 ft. And if I were to move the outlet closer, so as to use the original power cord, it'd be done to code, with 12 gauge wire.

I really just posted to understand if there was some other limitation with prepackaged so-called "125V" extension cords. I know how to build a cable from parts at Home Depot, but chopping the same sized premade extension is usually cheaper. Thanks to the replies, I realize these are good to 300V give or take. Makes sense, it was just the labeling that threw me.

I'm not trying to risk my motor, but neither am I trying to waste money. Yes, I just bought an $1800 jointer, but it was a stretch, one that I'd not have been able to make had I not been frugal with my other woodworking expenditures along the way.


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## Delete (May 19, 2017)

Hey Moosie it has been made more complicated than it has to be. The extension cord comes marked from the factory as 125V at 15A because thats what the plugs are designed for and rated for, they don't expect that your going to cut the plugs off and install a 240V plug and connection. 12 AWG is rated 300V, it's printed right on the wire casing and each wire including your ground is rated for that voltage at 15A.

If your house wire is 12awg not much point going 10awg even if there is a small difference in rating. Long shot but if your extension is much larger than your house wire, in a grounding situation if your breaker doesn't trip (this is why it would be a long shot) the fire will start inside the wall first before your cord blows.


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## BlueRidgeDog (Jan 2, 2019)

> I don t understand all the 10 AWG comments.


Their basis is that the cost difference is trivial, the gain from the cost difference is worthwhile and the specifications from the manufacture are a minimum. Goin up "one" size is not cost significant and is a safety margin. It is also not required or even recommended (i.e. those here that mention it are not advising you will have some issue with 12 AWG). I do it as I typically go up from a minimum rating. I also keep one size of stranded wire on hand for various applications.

Put another way, I am currently building a deck. There are code standards for the minimum for each section (beam, post, joist). I can build to the minimum, but I am building to exceed the minimum, but not in a foolish way, but just enough to have a margin of safety and error. I "can" span 10' on a beam, but will span 9', I "can" span 12' for my joist sizing, but will span 10'. So, you can use 12 AWG, but if you choose to go up from the minimum, then jolly for you.

In wiring my house I have done the same. There are several runs where code allows 14 AWG. I use 12 AWG. One, that is the wire I keep on hand, and two…down the road I may use that leg for another use, so even my lighting switch legs are 12 AWG.

Finally…I always follow the advice of my electrical mentor who had a habit of saying "fat wire and small breakers".


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## bigblockyeti (Sep 9, 2013)

You should be fine with 18AWG.


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## ibewjon (Oct 2, 2010)

18 awg?


> ?


 Bad advice. And using a cord larger than house wiring will not cause a fire in the wall if breaker is sized properly.


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## Delete (May 19, 2017)

No one said anything about a badly sized breaker, and it was stated it was a long shot, that means highly unlikely, Breakers are very reliable but not perfect, nothing seldom is, and there is always the guy who gets tired of a tripping breaker and hacks a bad solution.

I am sure 18AWG was said tongue in cheek. On a 25' cord running a 3 HP motor you would probably only use it once.


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## jacksdvds (Jun 13, 2015)

I just installed the same joiner. Had the same problem of too short of a cord. My solution was to run a new outlet from the existing outlet. Safer and no long cord to get in the way.


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## moosie (Jun 14, 2017)

> I just installed the same joiner. Had the same problem of too short of a cord. My solution was to run a new outlet from the existing outlet. Safer and no long cord to get in the way.
> 
> - Jack Lewis


That was my initial thought, but not practical in my situation. I share a garage with my wife's car, and the "virtual wall" between us is just a few support columns. The jointer is oriented toward that side of the space. I thought about bringing a 240 line over the ceiling and down one of the columns, but there's way too much activity there, with the car door opening, curious grandkids walking by, etc.

Because it's a garage bay, it's only 12 ft wide. So, my approach has been to wire the opposite - actual - wall, which also happens to be adjacent to the electrical panel. The run to the breaker is about three feet, and the cable I need for the machine is just about 17' total. That allows enough slack to sit nicely on the floor, but not be a mass of coils to trip over. The cord is already about 10 ft, so I'm talking about lengthening it by 7 feet, and at that point the total run from machine to the 20A breaker would be 20 ft.

The outlet is a duplex. I only run one machine at a time (DC is on separate line), and the TS plugs into the other, with the exact same setup, just a bit shorter run since it's in the center of the space, and not on the far 'wall' near the columns.

One way or another, by purchasing by the foot, or chopping a standard extension, I'll make a 17-footer, with one end wired directly into the jointer. The existing cable that comes with the jointer is 14 gauge, by the way.


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## WhyMe (Feb 15, 2014)

I'd buy 17' of 14/3 SJOW or SJOOW cord and buy a plug end for it. #14 SJ two conductor is good for up to 18A. NEC Table 400.5(A)(1)


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## ibewjon (Oct 2, 2010)

Yes it is. And 16 is rated for 13 amps, that is 1 whole amp to spare! But why be so cheap? Good to see moosie is using 12 awg.


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## ArtMann (Mar 1, 2016)

When you look at wiring standards, or deck construction requirements for that matter, there is already a hefty measure of safety built in to the requirement. Spending money for an additional margin of safety does not add any additional value. You can rely on your mentor but I will rely one my electrical engineering degree and 30 years of experience.



> I don t understand all the 10 AWG comments.
> 
> Their basis is that the cost difference is trivial, the gain from the cost difference is worthwhile and the specifications from the manufacture are a minimum. Goin up "one" size is not cost significant and is a safety margin. It is also not required or even recommended (i.e. those here that mention it are not advising you will have some issue with 12 AWG). I do it as I typically go up from a minimum rating. I also keep one size of stranded wire on hand for various applications.
> 
> ...


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## WhyMe (Feb 15, 2014)

I don't like using what usually is a chinese made extension cord to make up a cord for shop equipment because usually the insulation is thremo plastic and is stiff and doesn't roll up nicely. I rather use Southwire SJ cord because of the flexibility.


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## ibewjon (Oct 2, 2010)

What does 10 awg hurt? What I don't understand is all the " just use 14 awg comments". Of course, I am only relying on 42 years in electrical construction and maintenance, doing service work, running 5 million dollar jobs, and fixing the problems caused when engineers undersize wire, conduits, and cabinets. But I am not pointing to you personally. I have seen many times where the engineer wants to upsize the wire, forgetting that the conduits were just the minimum size. You wouldn't like my shop, all 6 and 8 awg to my 240v receptacles. 1" and 3/4" conduit. And mostly 10 awg SO cord. No, I do not need 600 v cord, but it has a tougher jacket, and didn't cost much more than 300v cord. But that is just me.


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## BlueRidgeDog (Jan 2, 2019)

Well don't get me going on engineers. As a near retirement CEO I have worked with many and there are some that will tell you (accurately) that to hold a cup of water you need a 1 cup container. They are right academically, but wrong functionally. Yes, a perfectly functioning breaker will indeed trip before your 14AWG wire burns your house down. Care to guess how many faulty breakers I have replaced in the various facilities I have overseen in the last 30 years? The recommendation to go upsize is just that, a recommendation. I simply make certain that the wire in my systems is not the weakest link and, as I said before, it is easier to have one spool of wire on hand for service cables and I want that one wire to exceed all specifications in the electrical sense and in the durability and flexibility of the jacket.

So perhaps I have a $50 cord on my $2.000 tool, but after rolling over it with a floor jack and dropping lumber on it 200 times, it is still serviceable. Electrical Equipment is the fourth most common cause of house fires, faulty wiring is the seventh.


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## sgcz75b (Jan 21, 2019)

Since you're saving pennies, try a couple of coat-hangers wrapped in duct tape. No use spending money needlessly on real wire. And if you don't have duct tape, masking tape has a pleasant smell while burning.


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## moosie (Jun 14, 2017)

No need to be rude…

Later guys…


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## runswithscissors (Nov 8, 2012)

Many of you guys are talking about 12-3 wire, but I think the correct designation is 12-2 with ground. The 3rd lead in a 12-3 wire can carry a load; the green ground wire is not supposed to carry a load. The reason for the 3rd load carrying wire is in setups that partially run on 120 and partially on 240, such as a dryer or range. The lower voltage is for running the clock or the motor, and thus a neutral wire is needed. Not sure why this is (except maybe for bottom line reasons), since Europe and Australia use 240 for everything, even very small motors and lights, etc. Which reminds me: in Australia, outlets and plugs are 2 prong only, no ground wire or plug. I'm sure there is some explanation.

As for the comment that manufacturers of tools must have a reason for the size wire they use: yes, they do-they want to squeeze every dime out of costs.

I don't mind plastic sheathed cords on stationary tools, but I hate them on portable tools-much too stiff, almost impossible to straighten out or wrap efficiently around a tool body.


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## WhyMe (Feb 15, 2014)

We are talking about a cord being 12-3. The same in building wire like NM-b will be designated as 12-2 w/ground. Cordage designation includes the ground in the numeric count, so 12-3 is correct for #12 cord with two conductors plus a ground.


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