Replies

1. 
   dwyates | Oct 12, 2003 08:00am | #1

   I have the same saw - and yes, the owners manual seemed contradictory from everything I'd read about wiring. I worried & wondered about this for quite awhile, until finally I contacted a Powermatic rep. & was told that was correct (huh?)! However, being hardheaded (and not able to find a 40amp breaker or plug) I opted for a 30amp breaker, 30amp plug, 10awg wire - works like a charm (so far!). I have't run anything huge through it yet, so it may come back to bite me, who knows. I even ran a PM15 (5HP) on the same circuit at the same time - didn't trip the circuit. I'm only a one-man shop, so I won't be doing that on a regular basis, but it was nice to know it could be done.

   It's a fine saw - will probably last me the rest of my lifetime. I feel very lucky.

   Good luck & enjoy the saw.

2. 
   LeeEschen | Oct 12, 2003 09:07am | #2

   The 30A and #10 would do OK for a 3HP, but I'd go with the 40A breaker and #8 COPPER wire for a 5HP, John.

   With the 30A, the first time you shove a large chunk of rock maple through your 5HP, pop goes the breaker.

   --

   Lee in Cave Junction, Oregon

   Gateway to the Oregon Caves

3. 
   migraine | Oct 12, 2003 10:56am | #3

   I'd go with the #8 wire, especially if you are any distance from the panel and you probably won't have a problem with 30 amp breaker, but 40 is preferred.  Mostly depends on your voltage to your shop/home and/or your voltage drop through the distance from the main breaker

   Make sure you keep the starter capacitors on the motor clean by blowing out the end of the motor on a regular basis.  Someday when the motor won't start, that will be the problem.  I was told by powermatic that this is common.  These thinks work by centripical(sp?) motion.  The switch opens or closes(I don't remember which)once the motor is at a certain speed it opens/closes(don't remember which one) If you have a problem and you need to open the cooling fan end of the housing, DON"T touch the capacitors-they will "Light up your life".  Just blow them out and keep the air nozel and the end of it safely away 

1. 
   rslatm | Oct 13, 2003 03:16am | #4

   Man! Talk about the Misinformation Highway! The start and run capacitors are located on the side of the motor and are sealed so no blowing out is necessary. The motors are called TEFC...totally enclosed fan cooled. The centrifigal switch is located inside the sealed motor housing. Taking the cover off the fan only exposes the fan. The cover keeps stuff from hitting the blades and curious people from poking their fingers at the fan and losing a finger. Basically the fan blows air around the "sealed" motor housing. I wouldn't let you do any wiring at my house...LOL

1. 
   migraine | Oct 13, 2003 05:43am | #7

   augh yeah, sort of.  The powermatic66 with the 5hp single phase motor uses a centrifacal/centripical(or however is is spelled) switch that activates or is activated by the capacitors.  Now I am trying to do this from memory, since my saw is still packed away in a crate from moving.  And you are right that the capaictors are on the side of the motor.  What I  ment is that the switch is located behind the fan and fan housing that you have spoken about.  This is required to be disassembled to clean out the switch .  Now I may be alittle rusty on the particulars of the motor since I havn't had the problem is 3-4 years and I may not be as articulate when it comes to this type of stuff.  My point was to make him aware of a "common problem" as the Powermatic technician informed me.  And to add, these motors are not totally dust proof in all areas, especially when you have the motor cover attached to the base of the saw. 

   Now as to my my wiring abilities.  I have wired many homes, shops and I have also done wiring on my own shop and  friends' shops where as I have had to install single phase power that was split and run through  a rotary converter and created a totally seperate three phase system with magnetic and manual power disconnects for multiple 3phase machines that also needed to have magnetic controlls wired to the 2 "nonconverted" legs.  Also including wiring transformers to balance loads on some european motors that were running "out of phase".  Let alone setting up a control system for turning on the converter at any place in the shop with a portable radio frequecy control.  Or, building a system that automatically turns on the dust collector when a machine that demands dust collection.

   Now, If I am still wrong with the "motor/starter capacitor switch" then correct me, just don't bash my wiring skills when you haven't seen them.

   In re-reading my post, I realize that I wasn't too clear leyt alone accurate and it was probably out of line to mention the dust and capicitor thing when the origional question was concerning breaker and wire size.  So, you have me there.

4. 
   PlaneWood | Oct 13, 2003 04:04am | #5

   1 hp = 749 watts or 5 hp = 3745 watts.  Divide that by 220 and you get 17 amps.  On full load, it might get up to 25-26 amps.  Block rotor current could go up to 35+.

   Check this web site - http://www.powerstream.com/Wire_Size.htm

   If it were mine, I'd go with 8 guage and a 40 amp breaker.

   PlaneWood by Mike_in_Katy (maker of fine sawdust!)
   PlaneWood

1. 
   jwallwork | Oct 13, 2003 04:39am | #6

   I took peoples advice and put in a 40 amp breaker and ran #8 gauge to the outlet, so I should be ok with the codes.  I've wired in a 50amp stove outlet, I couldn't find a locking type above 30amp, I  take it they aren't allowed.

   In wiring the cord for the saw, should I stick with #8 gauge or go with #10, I'm leaning towards #8, but am worried about it's flexibility, I'm planning on putting the saw on a mobile base and being able to wheel it around a bit.  Also are there any length restrictions I need to be aware of.  I'm thinking about a 15' cord.

   Thanks for all the advice and information from everyone.

   John Wallwork

5. 
   TKanzler | Oct 14, 2003 03:11pm | #8

   It calls for a 40amp circuit breaker and only 10 gauge wire. Is the breaker 40amp mainly for the initial startup pull and 10 gauge is fine for the actual running load?

   That's basically it in a nutshell.  That saw comes without a power cord, and if installed in an industrial setting, would normally be hardwired per NEC Article 430 Motors, Motor Circuits, and Controllers.  Per Art. 430, feeders and branch circuit conductors would be sized to 125% of the Table 430-148 full-load current that corresponds to the motor hp (not the nameplate FLA), with the [inverse-time] circuit breaker being sized at no more than 250% of the Table 430-148 value.  Overcurrent and overload protection for both the motor and the wiring is by the motor controller, not the breaker (or fuses, if they are used instead), so a breaker much larger than what you would use for non-motor circuits of a given wire gauge would be allowed.  The breaker is only there for short-circuit and ground-fault protection, NOT motor overload or overcurrent protection.  Article 440 Air-Conditioning and Refrigerating Equipment is very similar, by the way, and would explain why you might see an oversized (for the wire gauge) breaker in your panel for your central A/C condensor unit.

   The obelisked (t) conductor ampacity values in Table 310-16 (14, 12, and 10 gauge), which are limited to 15, 20, and 30A respectively by the footnote, can be used at the full Table 310-16 values for motor circuits (when wiring per Art. 430), or 20A for 14 gauge, 25A for 12 gauge, and 35A for 10 gauge (at 75C, and if the lugs, etc are rated for 75C).  Non-metallic cable, or Romex, has 90C insulation, by the way.

   But if you feel more comfortable using 8 gauge, there's certainly nothing wrong with it.  It's just a lot more copper than you need for a non-continuous load of about 20A (conductors are rated 40A at 60C, and 50A at 75C).

   Be seeing you...