Sub panel install

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Old 11-05-19, 06:46 AM
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Sub panel install

Hello everyone, hoping I can get some help, I want to install a sub panel in my shop, I have 208V WYE 3 phase 200 amp service. The sub panel would be placed about 100í from the main panel. Main reason is I got a 2 new 3 phase machines and want to install some exterior and interior lights but donít want to keep having to run wire all the way from one end of the shop to the other. My questions are is it possible to install a 60 amp 3 phase sub panel or would it be better to just go with a 100 amp ? And when installing up sub panel am I grounding back to the main panel or is it grounded close to where it is being installed?
I know this isnít really a DIY but Iím trying to save a little bit of money starting up a business, so any help would be greatly appreciated. Iíve already wired and installed our air compressor and car lift. From help from here and some of my maintenance buddies at work. Thank you all.
 
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11-05-19, 10:35 AM
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Is the shop attached to the main house where the main panel is located?
I saw no mention of a house and assume the 3-phase service currently serves the shop, but the OP wants a subpanel toward the other end of the shop.

My questions are is it possible to install a 60 amp 3 phase sub panel or would it be better to just go with a 100 amp ?
This would depend on the load you are adding; the 2 new 3-phase machines, lights and receptacles.

And when installing up sub panel am I grounding back to the main panel or is it grounded close to where it is being installed?
You will need to install a 5-wire feeder; 3 hots, 1 neutral and 1 ground. For a 60 amp feed I'd uses 4 - #6 and 1 - #10 Ground. For a 100 amp feeder I'd use 4 - #3 and 1 - #8 Ground. You will need a ground bar in the new subpanel, do not bond the neutral bus to the grounded panel box. No other grounding is required or needed.
 
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Old 11-05-19, 07:04 AM
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Is the shop attached to the main house where the main panel is located?

Yes you could install a 60 amp panel if that is all you need. Its breaker's rating back at the main panel would depend on the feed cable size or the subpanel amps rating whichever is less. Use a crystal ball to finalize your choice.

Do a load analysis of the house and workshop together (if not already), sample rules at the back of the NEC, before continuing with the project and selecting wire sizes.

You can do it yourself for a home workshop or a home office even if you are self employed and even if you take a tax deduction for that (in most cities). But a commercial building or rental house needs to have the electrical work done by a licensed professional (in most cities).
 
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Old 11-05-19, 10:35 AM
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Is the shop attached to the main house where the main panel is located?
I saw no mention of a house and assume the 3-phase service currently serves the shop, but the OP wants a subpanel toward the other end of the shop.

My questions are is it possible to install a 60 amp 3 phase sub panel or would it be better to just go with a 100 amp ?
This would depend on the load you are adding; the 2 new 3-phase machines, lights and receptacles.

And when installing up sub panel am I grounding back to the main panel or is it grounded close to where it is being installed?
You will need to install a 5-wire feeder; 3 hots, 1 neutral and 1 ground. For a 60 amp feed I'd uses 4 - #6 and 1 - #10 Ground. For a 100 amp feeder I'd use 4 - #3 and 1 - #8 Ground. You will need a ground bar in the new subpanel, do not bond the neutral bus to the grounded panel box. No other grounding is required or needed.
 
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Old 11-05-19, 07:58 PM
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If really penny pinching and no 3 phase loads in new panel you could go with 100 amp single phase and feed it with 2 #3 and 1 #8 copper. (or go with aluminum at #1 and #6)
 
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Old 11-05-19, 09:18 PM
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Yes it’s a commercial building, and as far a 3 phase machinery it is a wood pallet dismantler with a 10HP motor, and a saw with a 5 HP motor, but I have decided to go with a 100 amp panel, in case of any future installs. So everything including ground wire has to be ran and connected back to the main fuse panel, and no other ground at sub panel necessary correct? I did read somewhere else that the neutral and ground must not be bonded. Thank you.
 
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Old 11-06-19, 06:47 AM
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I have decided to go with a 100 amp panel, in case of any future installs.
Good Choice.

So everything including ground wire has to be ran and connected back to the main fuse panel, and no other ground at sub panel necessary correct?
Correct

I did read somewhere else that the neutral and ground must not be bonded.
Also correct. ......................
 
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Old 11-09-19, 10:48 AM
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Ok have panel wired at the main panel and wires connected at the sub panel, I see that the sub panel has a cross bar going to the neutral and ground bar, wouldnít I have to remove that since Iím not bonding them together? My main panel has the cross bar connected as well and seems to have the green bonding in the neutral bar. (Main panel was installed by a licensed electrician too btw) . Iím just a little thrown off by that.

I will get a picture of the main panel soon.
 
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Old 11-09-19, 11:27 AM
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Yes, in a subpanel, remove the (green) screw in the neutral bar and digging into the panel back, remove any cross bar or jumper wire running directly between the neutral bar and the ground bar.

For the panel or box holding the first whole-building disconnect for the service, the aforementioned items remain in place.
 
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Old 11-09-19, 01:35 PM
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I believe those are both neutral bars. You need add the ground bar bolted direct the panel back in one of those empty holes.
 
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Old 11-09-19, 01:59 PM
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I too believe the two bars are meant to be neutral bars when unbounded from the case. Modifying the bars to isolate one from the other so that one of the bars can be used solely as a ground bar is most likely not following the manufacturers instructions. Normally any internal connection between the two bars should not be removed or modified to make one of the bars a ground bar. Usually a ground bar kit needs to be installed per the manufacturers instructions.
 
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Old 11-09-19, 03:56 PM
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You need a neutral bar on each side for any GFCI breakers to attach the neutral.
 
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Old 11-09-19, 07:06 PM
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Maybe OP can read the instructions (label) and determine if it is OK to remove the strap connecting the left and right bars.
 
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Old 11-09-19, 09:04 PM
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It is not designed to be removed and used as a ground bar. It is insulated from the metal frame.
The true ground bar bolts direct to the metal frame.

The next question I have is that looks like a three phase panel. That is not DIY work in most cases.

Ground bar kit example

https://www.homedepot.com/p/Square-D...TACP/100165809

 
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Old 11-10-19, 05:54 AM
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It does not look like the wires were identified as to purpose.

Agree on the ground bar must be added, not remove the jumper between the neutral bars.
 
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Old 11-10-19, 08:26 AM
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The instructions read that the bar could be removed for panels used under 150amps, the panel did not come with the green bonding screw installed, it’s still in the plastic bag, but if it’s safer I will keep bars attached and just add a ground bar. I don’t plan on adding gfci, as I’ve been buying gfci receptacles . I will read the instructions again and will update.
 
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