Replies

1. 
   4Lorn2 | Dec 24, 2003 07:50am | #1

   Do you really need a neutral? Three phase equipment operate at a phase-to-phase voltage.  I would give voltages but it depends on what system your on. Could be 120/240v or 120/208/240, the most common three phase, 3P, arrangements in residential use but there are other combinations. If you don't need the phase-to-neutral voltage you don't need a neutral.

   You must, for safeties sake, have a ground. Ground and neutrals are not the same thing even though they are often, electrically, similar. You should have, IMHO, pulled in a ground. Code says you can use the conduit as a ground path but I think it is a poor practice. Doing it means a single loose or damaged connector can break the very important ground path.

1. 
   WorkshopJon | Dec 24, 2003 05:40pm | #5

   4Lorn1,

   A three phase plug has four conductors (3 hot and a ????) is it neutral or ground? I always figured ground. From this discussion I get the impression it should be neutral, but if that's the case, then how it the equipment grounded? That would require 5 connections.

   Jon

2. 
   gweisenburge | Dec 24, 2003 06:02pm | #7

   The saw is a Felder, a European, 7-hp machine. It has a four prong plug which until now I plug into a four-#8-wire, long, extension cord I've wired direct to the load center. Three of those are hot, of course, and one is wired to the center's ground bar. In this new shop, I'm running the three-#8-wire through conduit, and I thought I'd use the EMT as the ground/neutral, wiring the fourth tab on the wall outlet to its metal box. I don't believe the machine requires a neutral, but I'll call Felder today to ask that question.

   At this point, I don't know if I can run the fish in the 3/4-inch EMT without pulling out the 60-feet of three wires I pulled yesterday.  

   Thanks everybody for your help. I like it when everyday I get a chance to learn something new. I just wish I had the time to stop and think, but I must be in the new shop by the first of 2004.

   Namaste,

   Gary

   http://gwwoodworking.com/

1. 
   DaveRicheson | Dec 24, 2003 06:39pm | #8

   Gary, use one of the wires in the conduite to pull in two more wires. Don't try to push a fish tape through the conduite! When you do a pull out/pull in, you pull in the same wire you are pulling out and the exrat wire you need.  There is less likelyhood of skinning the insulation on the wire in the conduite this way, particularly if the pipe has a few bends in it. Be sure to tie down the wire you want to remain when you do the pull through, They will want to come out too.

   Pulling in a ground is the safest route to take,as 4Lorn said.

   Dave

1. 
   gweisenburge | Dec 24, 2003 07:20pm | #9

   Thanks, Dave, but I can't use a wire to pull a fourth one. I taped the three existing wires together about every four feet, as I was shown years ago by an electrician friend. Of course he did it correctly the first time. Either I remove the existing three and pull through a fourth, or try to push through the fish.Namaste,

   Gary

   http://gwwoodworking.com/

1. 
   DaveRicheson | Dec 24, 2003 07:39pm | #10

   I taped the three wire together about every four feet......

   That will likely make it nearly impossible to push a fish tape though. It will slide between the wire untill it hits the area of the tape and stop right there.

   Might be easier to pull them all out with a pull string attached to them, and then pull them all back in with the ground wire added.

   We have also taped wire together when using loose wire on some pulls. The feed man on the pull is responceable for removing the tape b/f the wire enters the conduite. We also add a pull string to most pulls and have even adde extra wires to some. Having a managemnt team that knows very little about electric work has taught us to plan for future changes that they haven't anticipated:)

   Dave

2. 
   gweisenburge | Dec 24, 2003 08:13pm | #11

   Thanks again, Dave. The reason I'm here, asking questions, is that I'm like your management team re: electricals, but I do want to put some forethought into this. I'm going to pull out the existing three and add the fourth to it and re-pull the four. Namaste,

   Gary

   http://gwwoodworking.com/

3. 
   rasconc | Dec 24, 2003 10:19pm | #12

   Not sure on your wirefill for 3/4 but would it not be a bad idea to have both a neutral and ground added if you wanted to use a 110 outlet from this feed?  Three 8's and a 10 may not allow you another wire.  I do not know if this is wise or not, how about it code wise?  I would be interested in hearing from our guys with Kleins on their hips.  Most of us do not deal with 3-phase and there are some subtle but significant differences I believe.

4. 
   gweisenburge | Dec 24, 2003 10:29pm | #13

   In my case, this is a dedicated run for my dual function, 7-hp saw/shaper, served by a 30-amp, 220-volt, 3-p breaker. I ran a separate 30-amp, 220-volt, 1-p for 110-volt and 220-volt outlets, served by a remote load center (or whatever you sparky's call them). The run is roughly 80-feet, with a junction box some 20-feet from the load center.Namaste,

   Gary

   http://gwwoodworking.com/

2. 
   jhausch | Dec 24, 2003 07:59am | #2

   3 phase (usually) is only run with a ground; and I am pretty sure that the conduit qualifies.  However, 4Lorn1 or some other expert will chime in - listen to them, I'm just a hack.

   Edit - 4Lorn1 and I were posting at the same time - go figure.

   
   

   ---

   Edited 12/24/2003 9:50:09 AM ET by Jim

3. 
   IMERC | Dec 24, 2003 10:15am | #3

   I'd never trust it. Pull a ground. A #10 bond would be adequate.

    

   Who ever invented work didn't know how to fish....

4. 
   junkhound | Dec 24, 2003 02:28pm | #4

   Pull the neutral fer sure if it is a wye connection or you want to put an outlet near the saw , no need if it is delta wound motor and no outlet.

1. 
   WorkshopJon | Dec 24, 2003 05:44pm | #6

   JUNKHOUND,

   Just thought I'd ask you too, see my post to 4Lorn1. Is it ground or neutral, as you are suggesting pulling a neutral.

   Jon