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will gilmore
01-30-2012, 12:01 PM
I have just moved into a new shop and I need to run wires to power some machines and welders. I have 3ph 208V at the panel. I measured the actual voltage to be 213V between phases.

Here are the machines:

Tree CNC for retrofit. 2hp 3ph spindle motor (6.2A@230V nameplate) This machine already has 30A fuses in place which I think I will keep. 5' from panel.

Bridgeport milling machine. 1.5hp 3ph spindle motor (4.4A@230V nameplate) 10' from panel.

Small shop built CNC lathe. 2hp spindle motor (6A @230V nameplate) VFD can take 1ph or 3ph. 20' from panel.

Manual lathe not yet purchased. 3hp max 3ph(10.6A@208V NEC FLA table) 25' from panel.

Miller Dynasty 350 welder 36A@208V 3ph nameplate. 30'-40' from panel.

Belt sander. 2hp 3ph (5.5A@208V nameplate). 30' from panel.

Air compressor. 7.5hp 1ph (32A@230V name plate) 65' from panel

Here are my questions:
Wires and breakers
Tree CNC - #10 THHN - 30A, 3 pole breaker.
Bridgeport - I've already wired this with #12 THHN and a 20A 3 pole breaker.
CNC Lathe - #12 THHN - 20A 2 pole or 3 pole breaker.
Manual lathe - #12 THHN - 20A 3 pole breaker.
Welder - #8 THHN - 40A breaker (Owners manual recommends 10 gauge wire with 40A time delay or 50A normal circuit breaker)
Belt sander - #12 THHN - 20A 3 pole breaker.
Air compressor - #6THHN, #6 Ground? - 50A 2pole breaker.

I would like to use two NEMA 14-50 style receptacles for the welder so I can plug it in in two places. They are rated for 50A with 3 conductors and a ground.

Should I combine any of the other circuits? For example plug the belt sander in to the welder plug or put the two lathes on one circuit. I think I need to combine at least one pair to have enough room in the panel.

What size conduit should I run? I have a hand bender for 3/4" EMT but I don't mind buying a bender for 1" or 1-1/4" EMT. Should I run everything in its own conduit, a couple bigger ones, or one big one for everything?

Should all grounds come back to panel individually or can they be daisy chained?

Wow, that is a long post. If you can contribute any help I would appreciate it.

txcncman
01-30-2012, 12:51 PM
There are both national and local electrical codes that need to be met. Personally, I would always have each machine on its own circuit for safety and maintenance reasons. Yes, the more copper and disconnects and circuit breakers you buy, the more expensive it gets. But, what is expensive is liability when someone gets hurt. Also be wary of wires sizes, I have found that what is usually recommended in charts and tables is one wire size smaller than what is needed to avoid voltage drops.

will gilmore
01-31-2012, 08:51 PM
Thanks for the reply. I've done all the reading I can and that's what I came up with. Any thoughts on conduit size?

txcncman
01-31-2012, 09:39 PM
If I have to pull the wire myself, it better be huge. There are charts available that will tell how many wires of certain sizes can be run in various size conduit. The problem I have seen is that these charts do not allow "extra room" for pulling wire through 90 degree ells or 90 degree bends. A good rule of thumb might be when you put the desired wires into the conduit you can still easily get your thumb inside. This should leave enough "extra room".

will gilmore
01-31-2012, 10:17 PM
I've come to the same conclusion about pulling. The chart says 9 #12 wires in a 1/2" EMT, yeah right. I guess I'll go 1 or 1-1/4 for the welder and air compressor and 3/4 for the other circuits.

Al_The_Man
01-31-2012, 11:21 PM
Pick up a Fish Tape and Wiring Lube.
Al.

underthetire
02-01-2012, 01:09 AM
Look up the nfpa code. It's usually no more than a 80 percent fill on conduit, and changes for every bend in the conduit. It speced for heat dissipation in the lines.

will gilmore
02-01-2012, 09:36 AM
I've never heard anything about accounting for bends in the conduit. Do you have any more information on that?

txcncman
02-01-2012, 11:11 AM
Only information I have is practical. Nothing written down. Once you get up to about #8 wire size, it does not like to bend very well. Common sense should tell you pulling 3 #8's though 1-1/2" conduit should be easier than pulling 3 #8's through 1" conduit, even though a chart (Conduit size (http://infohost.nmt.edu/~armiller/homerepair/conduitsize.htm)) says you can put 9 #8's in 1" conduit.

Al_The_Man
02-01-2012, 11:14 AM
This is why you need the wiring lube,:cool:
Makes wiring a cinch, you obviously need 2 people when pulling wires.
Using the lube you don't need to cut down on wire capacity for bends, especial on wide bend EMT.
Al.

will gilmore
02-01-2012, 11:27 AM
Fish tape and lube it is. Thanks everyone.

will gilmore
02-02-2012, 03:48 PM
One more question. I'm putting in two receptacles for the welder. I'm familiar with grounding boxes using a pig tail going to a screw in the box. What do I do with #6THHN wire. I don't think their are wire nuts that accept 4 #6 wires.

Al_The_Man
02-02-2012, 04:16 PM
I have distinct dislike of wire nuts, they were banned in the UK a long time ago.
If I have a few conductors to be terminated that large, I usually use a terminal block, in the case of grounds you can get common ground buss bar as is used in panels, neat, safe and efficient.
Especially grounding items such as welders.
Al.

will gilmore
02-02-2012, 05:40 PM
http://images2.mcmaster.com/Contents/gfx/large/7527k43p1l.png?ver=1274263

Are you recommending this style of terminal block? I've used these in electronics projects but it is ok for distribution?

Or this looks like it would work for grounding:
http://images1.mcmaster.com/Contents/gfx/small/2450k1p2s.png?ver=10420604

What are the professionals using?

underthetire
02-02-2012, 05:44 PM
I've never heard anything about accounting for bends in the conduit. Do you have any more information on that?

it's all in the NFPA 70E handbook. Not sure if its available on line or not. The book I have is about 4" thick. It all boils down to more bends= larger conduit for the same size wire, if your close to the fill capacity anyways. Just like you cant run SO cord or romex through conduit, its all about heat dissipation on the conductors.

Al_The_Man
02-02-2012, 07:17 PM
Are you recommending this style of terminal block? I've used these in electronics projects but it is ok for distribution?

Or this looks like it would work for grounding:
What are the professionals using?

That's the type of ground bar or a variation, the live terminal block is similar but has an insulated mounting.
Al.

cheetahcnc
02-02-2012, 07:37 PM
"Ugly's" has a good condensed code book, with most of your answers for a few bucks. I think I even saw it at H' Depot. As far as running your conduit, there are other options. I got the 4x4 inch trough with the flip top lid for the bulk of the wiring out of a new three phase service. Ran it down the middle of the shop. This way, drops and future changes are easier.

Jim

will gilmore
02-03-2012, 06:35 PM
That's the type of ground bar or a variation, the live terminal block is similar but has an insulated mounting.
Al.

Can you post a link of what you are thinking about?

Al_The_Man
02-03-2012, 07:08 PM
The Ground bar is similar to what you would have in any distribution panel.
For power there are these.
http://www.automationdirect.com/static/specs/edisonepdb.pdf
http://www.weidmuller.ca/system/files/webfm/downloads/pdfs/literature/LIT0902_Weidmuller_Power_Distribution_Blocks.pdf
Al.

will gilmore
02-03-2012, 09:30 PM
Ah yes. I have seen those before. Thanks.

will gilmore
02-06-2012, 10:06 AM
Ok. I think this is really my last question:
My Tree (http://www.cnczone.com/forums/vertical_mill_lathe_project_log/142284-tree_journeyman_320_b_retrofit.html) originally had three hot wires coming in plus a ground. In side the cabinet there is a 240/120 transformer to power some of the components (spindle speed motor, coolant/lube pumps, light, etc).

1. Can I remove the transformer and bring in a neutral to get 120V into the cabinet?

2. Does the neutral need to be broken at the disconnect? My reading of the code says it does not because it is a grounded conductor.

Thanks again.

Will

LeeWay
02-06-2012, 10:48 AM
I have been using this type connector in my shop.
McMaster-Carr (http://www.mcmaster.com/#push-on-wire-connectors/=g4qtj5)

I really like these. I too have a dislike for wire nuts.

I also chose to run the blue flex conduit with the plug in style connectors for all my lighting. That makes short wok of it.

I am using all 3/4" conduit on the walls, but almost went to 1". It would have been better I think.

will gilmore
02-06-2012, 11:02 AM
I have been using this type connector in my shop.
McMaster-Carr (http://www.mcmaster.com/#push-on-wire-connectors/=g4qtj5)

I really like these. I too have a dislike for wire nuts.

I also chose to run the blue flex conduit with the plug in style connectors for all my lighting. That makes short wok of it.

I am using all 3/4" conduit on the walls, but almost went to 1". It would have been better I think.

Interesting but I need to connect #8 wire and those only go to #12.

Al_The_Man
02-06-2012, 11:03 AM
1. Can I remove the transformer and bring in a neutral to get 120V into the cabinet?

2. Does the neutral need to be broken at the disconnect? My reading of the code says it does not because it is a grounded conductor.
Will

You can bring in a neutral
The neutral should never be switched or fused.
Wouldn't it be easier to bring in 240 and use the transformer?
Al.

will gilmore
02-06-2012, 11:46 AM
You can bring in a neutral
The neutral should never be switched or fused.
Wouldn't it be easier to bring in 240 and use the transformer?
Al.

I'm bringing in the 208V 3ph for the spindle motor. Servo PS will be on 208V 1PH. I'm worried that with the 208V input the 240/120V transformer will only put out ~104-107V which is more than 10% from 120. I want to run the computer and monitor on the 120V line inside the cabinet. Also, the machine is right next to the panel so bringing in a neutral means buying 4 conductor plus ground cable instead of 3+gnd.

Al_The_Man
02-06-2012, 12:44 PM
Items such as PC and monitors have switching supplies that are internally regulated and can operate with quite a variation in input,also you mentioned that your 208 is higher anyway?
You could always put a temporary feed onto the 208 and see what the transformer puts out?
Al.

will gilmore
02-06-2012, 01:07 PM
ok. Thanks.