Three phase panel used as single phase

[Sharpest]

In my fairly old shop building (build thread here) I have an old three-phase panel that was repurposed into a single phase sub-panel at some point. Is this kosher? Google says its ok but I would like as much verification as possible. I particularly want to ensure it is viable because I want to make some changes to it soon. Currently, the main panel has 8 slots, pictured here;



The top left double is a sub-panel on the opposite end of my 5000 sq ft building that runs all of the 110v lights and outlets that I have no intention of modifying at this time. The two top right single poles are hooked up to some poorly installed fluorescent lights that I have no intention of keeping. The bottom right double is an 8-3 type NM circuit hanging directly off the panel as sort of a ghetto extension cord with a 6-50R plug for my welder (Miller 210). The bottom left double is currently run to the three phase sub-panel in question, pictured here;



The large wire looping over the top is the disconnected three-phase. As long as space doesn't get too tight in the box, I will likely leave it in case I ever decide to reactivate the service. The orange and red wires are for a 20 amp 220 circuit that would likely get retained either on this panel or the main.

My immediate intentions are to have three 220v circuits coming out of the repurposed sub-panel and potentially add a few 20 amp 110 circuits. The three 220 circuits I want are as follows;

-30 amp hardwired for 80 gallon compressor that draws 23 amps
-50 amp welder circuit with 6-50R outlet on wall
-30 amp circuit with whatever outlet a kitchen oven uses

Since there is pretty much zero chance of the full amperage of these three circuits ever being drawn at once, I believe a 100 amp breaker on the main panel would be sufficient. Since my walls are unfinished, this will all be ran with THHN through appropriately sized EMT. The sub-panel is 2' to the left of the main and all of the loads will be within 10' of it so circuit distance isn't a concern. The unprotected romex circuits in the pictures will be removed and re-ran properly.

Thoughts, critiques or concerns?

 

[wyliesdiesels]

So u have 3-phase service?

 

[Sharpest]

So u have 3-phase service?

The exterior riser, service wires and breaker box are there but disconnected from the PoCo pole.

 

[theoldwizard1]

Ignoring the first picture ...

Is using a 3 phase box as a split phase "kosher" ? It probably would NOT pass an inspection if addition circuits were added.

Put in a new split-phase 240V/120V box next to it. Run the feed from the main to it. Parts should be between $100-$200.

 

[Sharpest]

I'm here for constructive criticism. I didnt wire the panels and I dont know who did so you arent going to hurt my feelings.

As to deficiencies on the main panel, off hand I recognize;

-The neutral for the sub-panel in question is jammed into the head of the buss bar on the main panel.
-The type NM is hanging loose out of the bottom of the panel without even a conduit clamp
-Un-used THHN coming into the panel from the EMT on the top right. Can easily be removed

Keep in mind the age of the panel. They didnt allow as much space for circuitry back in the day

 

[matt_i]

As cheap as circuit panels are these days, I'd junk both of them and sell the old wire as scrap copper and start with some new, modern stuff you can get breakers for at the box stores.

My guess is your utility is going to want minimum $5k plus a big list of machines and motors you are intending to run to consume the power, to activate a 3 phase service. Unless you have a commercial shop I'd just call it a day on 3 phase.

 

[Radix2]

If you think you might use it someday, leave it.

Panels are cheap.

Make a new subpanel for your new stuff and leave room to expand. Proper panel, proper wire, fresh working breakers, nothing to worry about all kosher and probably one if the less expensive moves you will make in a shop like that.

 

[4 FN 27]

My guess is your utility is going to want minimum $5k plus a big list of machines and motors you are intending to run to consume the power, to activate a 3 phase service. Unless you have a commercial shop I'd just call it a day on 3 phase.

Get a quote from the Power Company you might be surprised.

"My guess is your utility is going to want minimum $5k"

That is a keyboard "Guestimate". Not reliable. No offense. I learned the hard way...if you don't ask you don't get.

 

[md21722]

Being able to have 3 phase in my shop at a reasonable cost would be great. With it being there already, I would definitely call your power company and ask. You can get used 3 phase industrial equipment on the cheap because there isn't a large market for it. Even new, three phase can be a deal. Motors are less expensive and simpler. For single phase loads, I think a newer separate panel would be the way to go. Would clean things up nicely. Really depends on what kind of equipment you're running or plan to run, and how your power company charges.

 

[matt_i]

That is a keyboard "Guestimate". Not reliable. No offense. I learned the hard way...if you don't ask you don't get.

Agreed. Go get hard figures, put in a call to your utility's field engineer to come out and discuss, I've found them to be straight shooters. However in the industrial 3phase world there's no playing around with being your own electrician (unless you already are one!) everything from the pole to the meter base is going to be fully inspected, the panels cost considerably more, etc.

The other viewpoint is the utility runs as a very low profit business, they can't viably provide the additional wiring, metering, transformers, cost of crews to come and install their side of the deal....to a guy who turns a Bridgeport on twice a month to drill a hole or mill a slot...they really need to sell to a commercial shop, manufacturing operation or the like who is a regular user of power.

In any case, back to the OP, I'd recommend doing the research, and you can determine for yourself which path to take, then decide to upgrade your electrical to modern single phase switchgear, or get the 3phase awaiting in your panel.

 

[ww_big_al]

First, it is perfectly legal to use a 3 phase panel on single phase. You will shoot yourself when you need to purchase new breakers for it though.
I do see several violation though with your boxes.

White/gray wire is for neutral only. Not hot

Sub panels require a separate grounding buss bar. Grounds and neutrals CAN NOT be tied together except at the main power panel.

Upper right cable doesn't have a cable clamp

Boxes look ugly but salvageable. If you replace those boxes you would be require to bring them up to code. Requiring GFCI outlets/breakers and might need those ****** AFCI breakers.

 

[alfredeneuman]

First, it is perfectly legal to use a 3 phase panel on single phase.

Any listed product is required to be installed in accordance with its listing and labeling.
Unless there is a label somewhere that says it's listed for this particular purpose then it's not OK to do so.

 

[awdblazer]

panels are cheap
change it out

 

[Aceman]

I would absolutely change those ancient panels out, no question. There is no reason to screw with them when panels and breakers are relatively inexpensive.

 

[Sharpest]

Thanks guys, I guess I'll leave the three-phase panel in place to potentially reactivate later and get a new HUGE main panel. My shop is in a commercial district in a small town so I wouldn't anticipate restoring the three-phase power to be difficult if I ever needed it. I love the idea of having a lathe or mill some day but my dwindling free time due to my career has put a damper in that idea. A badass air compressor would be viable though.