Power Requirements for a Planer

      Make sure the wiring and breaker are beefy enough to satisfy the voltage and amperage requirements of the equipment you plug in. June 18, 2009

I have a 13 inch planer molder made by Jet. Itís wired for 115v. I have a 15amp breaker which trips constantly. Iím only lowering the blade by about 1/4 turn and it still trips. This doesnít seem right because I used to have a 12 inch portable Delta that never tripped, even when taking a big pass. Can anyone help?

Forum Responses
(Furniture Making Forum)
From contributor K:
That planer pulls too much current for a 15 amp breaker. You need 12 gauge wire running to it on a 20 amp breaker.

From contributor Z:
I agree with what contributor K said and I would also add that you do not use extension cords. Wire it up for 220 if you can.

From contributor C:
In addition to going with a 20 amp breaker, and no extension cords, I would recommend checking the planer blades. Dull blades can also be an issue, as well as blades in backwards (the blades will easily fit in either way on the JPM-13).

From the original questioner:
Can using an extension cord do damage to the motor at all?

From contributor K:
Yes it can. Too small of wire or too long an extension cord can cause a drop in voltage due to its inability to handle the current which can cause the motor (and the cord) to overheat.

From contributor J:
Check the amp rating on your planer first. If you have to run it through an extension cord make sure you run it through a big enough cord.


Itís not really a lot of difference between a cord and wires in the wall when you have the right size wire. Also if your motor is only 15A then you could just have a bad breaker.

From contributor A:
People often forget about how much wire is in the wall, meaning how far the outlet is from the panel. Most outlets in houses are wired with 14 gauge wire. They run it for miles. Like others have mentioned you need to run 12 gauge either in the wall or run a 12 gauge extension cord to an outlet next to the panel.

From contributor S:
A clamp-on ammeter will be useful - almost imperative - in your diagnosis. It could be the motor on the planer is defective. You also need to be mindful of voltage, as a motor starved for voltage will try to compensate by drawing additional amperage, which exacerbates the problem.

A typical 115 volt receptacle is not rated for more than 15 amps. To simply replace a 15 amp breaker with a 20 amp breaker is (technically) not a good idea. To get a true 20 amp, 115 volt circuit, you should go to what is commonly referred to as an "RV plug". (Again technically-speaking) you also need to change the plug on the end of your power cord. When diagnosing such problems, always check the simple things first - always! I never miss an opportunity to write that down as it helps me remember to practice what I preach!

The preferred method of bragging about how powerful a tool is to point out the current draw of the motor. This is purely a marketing gimmick (and I believe to be blatantly false and misleading advertising).

Doing the same amount of work, a high quality motor will draw less amperage than a low quality motor. Being driven by a deception-oriented marketing department (and based on a false pretense), a manufacturer can actually benefit by building an inferior motor. Their only motivation then is to keep the current draw of the tool compatible with a typical 115 volt, 15 amp circuit.

Your planer is what it is - you need to determine whether or not you are supplying adequate voltage and amperage to the motor - and if not, why.

From contributor E:
I would recommended having a licensed electrician look at what you have and let hime help you to decide what you need. It is possible the motor might run on 110 or 220V. If this is the case running it at 220 will draw less current.

The important thing to know is you canít just go from 110 to 220. There is some rewiring in the motor you would have to do to make this possible. Another thing to keep in mind after you make sure the blades are sharp and in the right way is to listen to the motor when you start it. Don't try cutting anything until the motor is at full speed. Motors always draw more than their full load current when starting so any additional load at this point would for sure blow any breaker you try to use. Never change a breaker to a bigger sized breaker just to keep it from tripping. They trip for a reason and the wire probably isn't rated for the bigger breaker.

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