Electrical Sub Panel Recommendations Wanted

So I have been renovating and setting up my shop. The previous owner/s were hacks of the highest degree. I basically gutted the entire buildings wiring. What hasn't been gutted will be as I have been working through things one circuit at a time and unfucking it. I have 240 high leg three phase which is awesome, no converters to deal with. Whats not awesome is I'm out of breaker spots already for the current single phase circuits. I rewired the box and left room for two 3 phase breakers. I am thinking at this point a sub panel is the way to go. I have 8 pieces of 3 phase equipment that I need to wire up and plan to add a CNC lathe and mill into the mix in the next year.

Current panel is 200amp. Just looking for recommendations from people who have shops before I blindly trust the electrician.
I am mostly done with fixing the hackery but want to figure out my sub panel before moving forward any further. The other reason for wanting to go the sub panel route is this panel is on the opposite side of the building and next to a garage door and running conduit to the machines means going over the garage door which is annoying. Current equipment is a knee mill, two lathes, a shear, horizontal and vertical band saws and a drill press. Want to be prepped to add a 3ph air compressor, cnc mill and cnc lathe.

I did a subpanel on my setup, I just ran out of circuits. The service is 200 amp, the sub is fed from a 100 amp breaker in the main box. How were you planning to feed the sub? The cabling between the main and the sub needs to be in conduit.

Tom

TDegenhart said:

I did a subpanel on my setup, I just ran out of circuits. The service is 200 amp, the sub is fed from a 100 amp breaker in the main box. How were you planning to feed the sub? The cabling between the main and the sub needs to be in conduit.

Tom

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Correct, I have run every new circuit in conduit. A boss I worked for told me in shops EVERYTHING is run outside the wall, all electrical in conduit. This is obviously more expensive but is worth it in my mind. Just curious what size panel you would run, is 100amp the max for a breaker? How big did you go panel size wise? How many amps do a CNC mill/lathe need? Obviously that is very subjective, I will likely be getting a Fadal and a 90's Mazack lathe. Seems to be the best bang for the buck, but you know how plans like that go.

In Minnesota you aren't able to do commercial electrical work unless you are a licensed electrician. Minnesota is *very* strict about it. In fact you can't do residential electrical work unless it is your residence and there are a whole lot of restrictions at that. The electrical inspector in Minnesota will catch you and they will gleefully make sure that everything you touched has to be ripped out. The state is widely known to be very stringent in their enforcement.

If you want to do it yourself, my recommendation is find a electrician that will work with you one way or another. I've found independent electricians (and plumbers and HVAC) close to retirement have been willing to work with me in advantageous ways. For instance I or one of my employees will help them fish wire so they don't need to bring a helper. Or they will let me supply some of the material. I buy my 3 phase breakers and disconnects on the secondary market pay 1/5th or 1/10th of what they cost new from the supply house. They complain some, but it's worth a little complaining when you can spend 5 minutes on eBay and save $600.

kustomizingkid said:

How big did you go panel size wise? How many amps do a CNC mill/lathe need? Obviously that is very subjective, I will likely be getting a Fadal and a 90's Mazack lathe. Seems to be the best bang for the buck, but you know how plans like that go.

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At 200'ish volts, plan on 100 amps for an old Mazak lathe. Which, incidentially, is what you need for a brand new Mazak VMC. And a big welder. I've had 100 amp 5 pole (3 phase + neutral + ground) pin and sleeve cord drops put in. The connectors cost some coin, but it allows me to unplug the lathe and plug in the rarely used MIG welder and not have to have two circuits to do it.

In terms of breakers: Breakers up to 100 amps are usually reasonable. Above 100 amps they start to get expensive quickly.

I didn't do anything personally... been helping and learning and am trying to educate myself. Working on a budget and just picking through this cluster as I can and can afford to. I just want some advice from the brain trust before I install shit that isn't the right stuff. I just don't know anything about it and don't want to spend big bucks and go down the wrong path.

Leave your current 200 amp panel for your 3 phase equipment, install safety covers to the unused spots.
looks like a 3 phase Delta feed.
Add a 100 amp 2 pole braker to the existing panel pulling off the two lower volt legs.
(never use the stinger, higher voltage leg for single phase feeds)
Then add a 100 amp single phase sub panel, save your self some bucks as you already have the 3 phase panel in place.

kustomizingkid said:

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What is that panel mounted on ?

Looks like 1" foam board cut by a drunken beaver with dull teef....

I don't know anything about Minnesota. But, in my experience in other parts of the country:
You greatly increase your chances of flying under the radar if your electrical looks legit.
If the fire marshal comes in for your inspection, and the electrical looks hack?
He will be the guy that gets the ball rolling that will force you to provide the permits and proof it was done by a licensed contractor.
This means metal conduit (plastic is for pussies), in proper hangers, hung level and plumb.
As already mentioned, safety covers in any un-used breaker slots in the panel. That is a huge red-light for an inspector.
And, sizing everything correctly. Don't feed a 60amp sub with a 100amp breaker kinda thing.
And, just as you are doing, educate yourself. This place has a bunch of guys on it who can answer any electrical question you could come up with.
I'm not one of them LOL! But, I can do a professional looking install.

digger doug said:

Looks like 1" foam board cut by a drunken beaver with dull teef....

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I did not cut that board. I've never even been to Minnesota!

digger doug said:

What is that panel mounted on ?

Looks like 1" foam board cut by a drunken beaver with dull teef....

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Thats the NICEST thing the previous "contractor" did in this place... I don't have enough time in my day to go through all that, I will post some pictures. the funniest thing was all the outlets that had tape over them. The previous owner was like "don't use those they burn stuff up"... Had them on the high leg. The two conduits running out the right side of the panel are the new runs that have been installed. Those are a single phase 240v run for my welders and a run of 110v bench height outlets. Like I said I am just working through this with a local electrician one thing at a time. I got all the machine tools moved into the shop and they are sitting dead on the floor so getting them wired up is my next top priority. Obviously once the final breaker locations are established I will clean up the panel. Can you just buy a new panel cover and start fresh? Again very ignorant in this field and the electrician charges by the hour. I like to have the exact plan ready and conduit cut and bent before he shows up...


So if you are going to be running a CNC mill and lathe 200 amps really isn't enough? Again I don't know anything about this.

kustomizingkid said:

So if you are going to be running a CNC mill and lathe 200 amps really isn't enough? Again I don't know anything about this.

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I run three SS haas mills, one Brother Speedio, and one O&H HL20 lathe, and the air-compressor, all at the same time, off phase-converter generated 190amps.
You will be just fine.
Also, the haas's data plate says: 70amps/80max. They have all been running on the 30amp slow-blow fuses that have never blown, for many years.

I had a buddy that was running three SS haas mills just like me, and a haas SL20 lathe, all on a 100amp city 3-ph service, no issues.

wheelieking71 said:

I did not cut that board. I've never even been to Minnesota!

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To be honest....the panel wasn't installed yet, so I can add "...in the dark", to the description...

See if you can find a good deal on buss duct

Everything on ebay is a million bucks now, but used to find it reasonable.

You can hire an electrician to connect it and should be good to do it yourself from the switchboxs down

I'm going on a picking mission... a friends family is in the demo business and he has a corner of a warehouse full of panels and conduit filled with wire. We will see what I can dig up, first I need to tear another wall down.

To feed a subpanel you can use a "feed lug" or "pass through" is another name for them. They are just a lug that plugs in like a circuit breaker, but low enough to stay under the metal knock outs, and will feed the full 200 amp load out to the next panel. The one I have feeding my panel is rated for 225 amps.
I have a main breaker in the subpanel to turn off the entire panel without going out to the pole if I need to shut it all off. This panel will in turn have its own pass through in it to feed the full 200a to the next panel as well.
Not all boxes are rated to use these so if looking at boxes maybe check this is a possibility.
Sure is nice to have plenty of power where you need it.

Yes, you can get new covers. Go to ebay or zoro. $20 to $50. Save the old one that should have a bunch of yellow stickers on it. They can look up electrical permits for a given address, but having the yellow sticker there can get an insurance or fire inspector calmed down in the meantime. Minnesota does track the number of circuits in a panel and the number of panel at an address. So having one yellow sticker there doesn't get you off the hook for unpermited changes.

Main breaker / service size is going to be what really limits what you can run. You can have 1000 amps of breakers in that size panel, but you will trip the main breaker before then.

I'm going to take some more pictures of my layout and where my current equipment is placed and where I plan to add future equipment. I just want to put the right money into this job and be prepped and ready to add a CNC mill and lathe and not spending more in the future due to poor planning.

First recommendation to answer your first question is use a panel box that takes the same style breakers your current box takes. It sucks going to add a circuit and finding you’re lacking a breaker or that the 20 amp breaker you’d planned to use won’t fit. Second recommendation is to read the NEC code book. Best thing about electrical is there’s NO GREY AREA! It’s as black and white as anything I’ve ever encountered. The NEC book leaves nothing to interpretation. That being said, you can do things like ganging up three single phase breakers to make a three phase breaker. Pin them together with a bit of welding filler rod. You can get single pole/single phase breakers up to 50 amps and single phase is always cheaper than 3-phase stuff. Agreed with above, 100 amp breakers, even 3-phase are relatively affordable. Above that they become big money. My recommendation is to stick with a main power panel and break off 100 amp panel boxes where you need them. 100 amp does a lot of work at my shop and running sub-panels or load centers even saves time. Put the box where you need it and put outlets however they’re needed at the box. Additionally, load centers are a bit cheaper than sub panels. If you have circuit protection in the main panel box with a breaker you don’t (REALLY) need another breaker in the box. It can’t hurt though. Lastly another thing to look into is legal “temporary power” options. I work for the movie studios and there’s relatively nothing permanent in my world. Set up a shop for a movie, shoot the movie and break down the shop to send it somewhere else. Studio lighting is high draw stuff and we use electrical connectors made for the task, such as these:

Heavy-duty 16 series Camlok Cable Connector: Rated up to 400A

They’re rated for 400 amps, totally code legal as “temporary” power, cheaper to buy than high amperage multi-pin plugs and receptacles. Plus since you’re on a delta system, also as mentioned above you don’t want to run ANY 110V stuff off the spike leg. So color code anything you do to make certain you never plug a 110v tool into the high leg. Pro tip: most LED work lights will handle the higher voltage... for a little while. And they shine like the SUN!!! Still don’t advise using the high leg for ANY 110V application.

Anyhow, follow the book, it’s very simple. Get yourself some conduit fill charts and ampacity charts printed out for easy reference. Beyond that advice don’t shock yourself. Make sure you’ve got at least the external disconnect and maybe more downstream so you’re not hot stabbing or working on live circuits.


Jeremy

I like square D brand breakers and panels. But i agree with previous poster use the existing brands so you can swap breakers around, even if just to test breakers. Do not use Zinsco or federal pacific.
Bil lD

With the high price of zinsco breakers doent that mean they are better?