# Shop Power



## Rozlo (Nov 6, 2015)

I'm looking to install power to my shop.  I'm only going to have approx 150amps of 220 single phase.  Is this going to be enough to run 3ph equipment?  I know you cant run it all at once but just need some help on this.  I have a 200amp service to my house and want to pull a 150 amp sub panel.  My son in-law is an electrician so it will be to code for sure.  But I just need some help and see what other guys have.

Thanks
Bill


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## GLCarlson (Nov 6, 2015)

Rozlo said:


> I'm looking to install power to my shop.  I'm only going to have approx 150amps of 220 single phase.  Is this going to be enough to run 3ph equipment?  I know you cant run it all at once but just need some help on this.  I have a 200amp service to my house and want to pull a 150 amp sub panel.  My son in-law is an electrician so it will be to code for sure.  But I just need some help and see what other guys have.
> 
> Thanks
> Bill



A hundred amp 220 subpanel has worked fine for my shop (but I have 400A to the house, so I've got headroom). Biggest 3 phase motor is 5 hp (way under a 100 A draw even after converter). Get a big panel- you'll be adding circuits as time goes on; I use one per major machine, plus separate lighting and multiple power outlets (3 circuits there).  Of course, if your 3 phase stuff is 50 HP, you may have a problem. If you're typical of most of us, you've got a bunch of 1-3 hp motors. No issue at all.

Added: Re 1 HP = 746 watts. Yes, but that's theoretical. If you have real motors (not theoretical ones) you have some losses. Old motors are around 65-75% efficient, modern ones are around 85%. So a horse is a kilowatt, for walk-around calculations that'll leave you some space for error.  Further comments re base loads (lights, etc) are very appropriate. Like others, I like LED lighting- lots of lumens, aimed in useful directions, at a great price.


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## Chiptosser (Nov 6, 2015)

Most likely, you will have plenty of power for what you plan on operating.
Do you have a list of the motors and equipment that you plan on running?


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## Tin Falcon (Nov 6, 2015)

As others have said should not be a problem. 

Depends on motor size and number of machines. Also types of machines. and how many machines can you run at one time. 

A 100 amp 220 panel will provide just under  30 HP of power. 
1 HP is 746 watts.
Unless you have cnc machines  you will likely only run one machine at a time and may have a compressor and or a dust collector running at the same time. 

Make a list of all the machines you plan to use . your electrician should be able to help you select the right size panel. 

And do not forget other things like refrigerator, microwave etc if you plan on having them. leds really reduce lighting draw if you afford the bulbs . I do like my daylight LEDs.

Tin


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## kvom (Nov 7, 2015)

I'm normally running only one machine at a time, and the other power users that are on at the time are lights, air compressor, and water heater.  Largest 3PH motor is 7.5HP.  Your main issue will be sizing wiring and breakers for largest anticipated load.


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## BobsModels (Nov 7, 2015)

Bill

Ten years ago I moved to a new place and had the pleasant opportunity to have a new building for my shop.Of the many Items of importance the electrical was high on the list.I have eight 3ph machines.They are driven by either a VFD or Rotary converter.The largest is a 7.5HP air compressor.I put in 100A 220v from the house to building.From the shop building main I had two sub panels, one for all the 3ph equipment and one on the far side of the building so I could reduce wire run lengths.Building is 60 feet long and has four rooms built in it.Since I was not sure I would always use a rotary or a VFD for a particular machine I set up a distribution panel off of the 3ph sub panel.For each machine I have a disconnect box.The disconnect box has fuses which are custom fused for the size of the motor being fed not the size of the wire going to the moto. The point is I want the motor protected and the wire is always way larger than the motor draw.Use special slow blow fuses.From the distribution panel to each disconnect box I ran #10 wire (to minimize voltage drop) for 3ph 220v ie 3 wires.I also ran #12 wire for a single phase 220V ie 2 wires.In addition I ran a neutral associated with the 220V so I could create 110V if needed.Of course there was a ground wire run for each ie 2 ground wires.Basically the rotary was fed from the 3Ph panel and its fused output went into the distribution panel to feed all the 3ph.The distribution panel had several power relays in a configuration that if for any reason there was a power hit the panel would drop out all the feeds (every wire including the neutral) to the disconnect boxes.The only way power could be restored was with a manual reset.This was primarily for safety so I would not have a machine just start right back up when the power came on.I could clear the cut or whatever and hope for the least amount of damage. The power relays were tied to the light circuit so when I turned off the lights at the end of the day all power was dropped.That is the basics.At each machine I have available any power combination I want.I can take just the 220V and hook up a VFD or run the 3ph directly.If I have other attachments on the machine ie lights, power feed etc I have 110v.Adds to the cost but I will tell you ten years later when I needed to change how some machines were run it made it real simple.I suspect you might ask, I have a friend who was an industrial electrician.He laid our power for factories.He worked with me to make sure everything was up to code.
It was mentioned earlier make sure you account for stuff always running ie lights, mine pull 18A if all on so I have several extra switches so I can turn on what I need.The refrig, microwave, fans (I have ceiling ones cuts heating bill with ten foot ceilings), and any other little thing, they all add up.My guess is your plan for 100A should be just fine.I actually did a test and turned every tool, light etc on for about ten minutes and during that time kicked the air compressor on.No light diming and the input from the house was pulling 94A with the air compressor running.The air compressor uses a VFD with 6 sec ramp so I really did not expect a problem.I was satisfied that all was working well.
Bob


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## Rozlo (Nov 9, 2015)

Thanks
Bob
It sounds just like my story.  I'm going at this one step at a time.  But I like the way you set your shop up.  I going to get this all laid out and put some of this down on paper so my son-inlaw can go through it.  it makes alot of sense for what I have.  Only have 2 or 3 machines 3PH but maybe I will add more.  I do have a couple of big draw welders.  But hey never have everything running at the same time.  
Thanks
Bill


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## kvom (Nov 9, 2015)

I have 400A service at the street but had only a 200A meter base.  To have a 200A shop panel I had to upgrade the meter base.  Fire department wants single cutoff to all power. 

In your case you have a 150A off of a 200A main, so you have to add in any load in the house to what might be used at any one time.  Probably won't be a problem, but having your BIL estimate max house current draw wouldn't hurt.

I have welder outlets in my shop but they're on 30A breakers.


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