220v in a room with no 220v outlets?

4651 Views 35 Replies 14 Participants Last post by kp91, Nov 13, 2017

4DThinker

Discussion Starter · Nov 10, 2017

In the CNC room of our new fabrication lab no one thought to install 220vAC outlets for our eventual upgrade to 22v spindles.

Probotix sells a transformer: PROBOTIX Step Down Transformer.

I'm curious if anyone here uses it, and how well it works?

4D

1 - 20 of 36 Posts

kp91

· #2 · Nov 10, 2017

4D,

We use step up transformers for a variety of equipment, but you have to account for the current draw and heat. Going from 110v to 220v will double your current, and current flowing through a conductor generates heat.

It will work, but you might want to look at options for a 220v circuit in the long run.

DaninVan

· #3 · Nov 10, 2017

Just a thought, but if there was a run of 14/3/1 or 12/3/1 feeding a split receptacle (dedicated ccts), and it could be sacrificed, you could tap into that for your 220V.

harrysin

· #4 · Nov 10, 2017

"Going from 110v to 220v will double your current"

Are you sure about this Doug.?

Reactions: 1

mgmine

· #5 · Nov 10, 2017

Why not simply run a new 12/2 line or disconnect one going to the room and make it a 220?

Knothead47

· #6 · Nov 10, 2017

If you are running 220V, 12 or 14 gauge, IMHO, is too light. Check at Lowe's for a book on electrical work or the local library. Used book stores are a gold mine. I have found some great books at McKay's, if you have one close. I have a book but cant' find it.

Cherryville Chuck

· #7 · Nov 10, 2017

DaninVan said:
Just a thought, but if there was a run of 14/3/1 or 12/3/1 feeding a split receptacle (dedicated ccts), and it could be sacrificed, you could tap into that for your 220V.

Not necessarily Dan. If that receptacle is wired properly both sides of the plug-in will be on the same leg in the panel. Otherwise you'll have 220 phase coming back on the neutral.

Cherryville Chuck

· #8 · Nov 10, 2017

mgmine said:
Why not simply run a new 12/2 line or disconnect one going to the room and make it a 220?

That might be the answer Art if there is a dedicated plug with no branching. The wires at the distribution panel could be reconnected to a 220 breaker. The plug-in would then have to be changed to one that only allows 220 volt appliances.

DaninVan

· #9 · Nov 10, 2017

Misspoke

Cherryville Chuck said:
Not necessarily Dan. If that receptacle is wired properly both sides of the plug-in will be on the same leg in the panel. Otherwise you'll have 220 phase coming back on the neutral.

Sorry, I should have said a 'split receptacle'...obviously if it was an existing cct., it was originally wired correctly (or as you point out it'd trip the breaker instantly).

kp91

· #10 · Nov 10, 2017 (Edited)

harrysin said:
"Going from 110v to 220v will double your current"f

Are you sure about this Doug.?

You got me... It was supposed to say that the current on the 110v line will be 2x what the current draw of the load would be on a 220v circuit

If the spindle would draw 10A on the 220v side, you would see twice that plus transformer loss load on the 110v side.

More proof that long nights and forum posts don't mix!

Gundawg

· #11 · Nov 10, 2017

If you have a dedicated circuit meaning it does not feed any other load you could convert it to 240V if you have room in the panel for a 2 pole breaker. A licensed electrician might be the way to go here he can tell you in a couple minutes your easiest route. Post some pictures of the panel I might be able to help. You need to know what your load requirement is for the new spindle this will determine the wire size needed the length of the run will also play into the wire size requirement. The breaker is sized to protect the wire the wire is sized for the load. Usually a step down transformer is used when you have a commercial building with 480V service. A transformer can step up voltage or step down voltage it has to do with the turns ratio of the transformer if it has a 2-1 turns ratio and you feed 480v in the primary side you get 240v out the secondary. In your case if you feed 120v in the secondary side you will get 240v out the primary. This would not be ideal there are some losses.

Mike

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DesertRatTom

· #12 · Nov 10, 2017

This is why the good Lord gave us licensed electricians. If I were thinking of adding a 220 line, I'd hire an electrician and consult with them before installation so they know exactly what to install. As a callow youth, I rewired the school gym's 440 lines to power theater lighting dimmers for a show there, but now I know I'm mortal and I'd never try that again. Lucky I didn't kill myself back then. For a home shop, I'd be surprised if it cost more than $500 and materials to have a 220 line installed, or less to tap into the the clothes dryer's 220 circuit. But even then, you still have the possibility of burning up your motor.

4DThinker

Discussion Starter · #13 · Nov 10, 2017

I appreciate all the advice. This is for a state college fabrication lab and our budget has been cut to the point where we are considering laying off temporary hires (critical to our mission) and so. The students pay a technology fee for every hour credit the sign up for but that also has been raided to finish tooling up our brand new fabrication lab.

So if we can get by without pay for an electrician to come and run new lines this transformer is just one option we are considering. The other option is to keep running routers until the tech budget has a few years to catch up with the spending.

MikeMa

· #14 · Nov 10, 2017

If it were me, I would run the routers till you can get the electrician in to do it right. I would be concerned the transformer wouldn't be able to provide clean enough power for the spindle, shortening its life considerably.

kp91

· #15 · Nov 10, 2017

Use routers, sell projects, use funds to upgrade equipment...

Sounds like a good business education as well as technical one!

Knothead47

· #16 · Nov 10, 2017

Raise money with a fund raiser. Jacks or better to open?

Gary Salisbury

· #17 · Nov 11, 2017

harrysin said:
"Going from 110v to 220v will double your current"

Are you sure about this Doug.?

Don't you mean that the current will be half not double?

Gary Salisbury

· #18 · Nov 11, 2017

Just my humble opinion but why do half-assed work? Bite the bullet and install a dedicated 220VAC circuit.

Don't forget to also do "insolated-isolated ground." It will guarantee that no noise comes back into the power line and possibly cause scrambled digital operation. That just means a special isolated ground outlet with the ground going back to the building load center. This should be a basic when installing computer-controlled equipment.

artman60

· #19 · Nov 11, 2017

Man, if I only lived closer. I would gladly trade running and wiring your 220 needs for some cnc schooling. Any vocational schools in the area that might donate the work?

Gary Salisbury

· #20 · Nov 11, 2017 (Edited)

Cherryville Chuck said:
That might be the answer Art if there is a dedicated plug with no branching. The wires at the distribution panel could be reconnected to a 220 breaker. The plug-in would then have to be changed to one that only allows 220 volt appliances.

Minor point:

1. The 110VAC line would have to be a 20AMP line (#12 wire) If it is 15AMPS, then the wire would be #14 which is probably too small for a 220VAC line.

2. The 110VAC line has a colored wire for the HOT and a white wire for the NEUTRAL and a green for GROUND. The white NEUTRAL would have to be taped a different color on both ends to be in code. White NEUTRAL wires can NOT be used to run HOT lines. Electrical codes vary from state to state but that is what NEMA says.

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