3 Phase 208 to Single Phase 208

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naplespete57

naplespete57

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Eastern Kentucky
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Project Manager in Conveyor Industry
Title: Compatibility Check: Using 2 Legs of a 3-Phase Panel for Single Phase 208 Equipment - Potential Risks?

Hello everyone,

I have a question regarding the compatibility of a specific piece of equipment with our electrical setup. We have an expensive piece of equipment that requires single-phase 208V power supply. Currently, we have a 3-phase panel, and we are considering using two of the legs from the panel to power this equipment.

I understand that 3-phase power is 120 degrees out of phase, while single-phase power is 180 degrees out of phase. Although this setup is commonly used, I want to ensure that there are no potential risks of damaging the equipment or causing it not to function correctly. Will be reaching out to the manufacturer's rep as well.

Has anyone had experience using a similar configuration? Are there any concerns or precautions we should be aware of to protect our equipment?

Any insights or advice you can provide would be greatly appreciated. We want to ensure the safety and proper functioning of our equipment, and we value your expertise in this matter.

Thank you in advance for your assistance!

(Note: If you have specific technical knowledge on this topic, please feel free to share your insights.)
 
Done all the time, nothing to worry about.

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In fact doing it any other way is what I would be hesitant about. If you derived a new 208 source via a transformer, you would have to decide where to ground it and every option would make "funky" line to ground voltages.
 
Question back to the original poster: is this equipment specifically designed and sold for the North American market, or is it something designed for a different market and then imported?

If designed for North America and specified for 208V, then you will have no problem using two legs of a three phase 208/120V supply. Essentially the only way you get a useable 208V here is as two legs from 208/120, so no one would design specifically for a different 208V configuration.

If you are talking a foreign import, then anything is possible and you need to be extra careful double checking that the system is compatible. You need to figure out what the equipment was really intended to use, and then see if what is available in North America actually matches in the relevant particulars.

-Jon
 
naplespete57 said:
I understand that 3-phase power is 120 degrees out of phase, while single-phase power is 180 degrees out of phase. Although this setup is commonly used, I want to ensure that there are no potential risks of damaging the equipment or causing it not to function correctly. Will be reaching out to the manufacturer's rep as well.
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Single phase power has multiple meanings.
1. An individual line-to-neutral circuit, with only one ungrounded conductor.
2. The 3-wire 120/240V split phase system. Common for single and duplex homes
3. A 240V circuit derived from the two ungrounded conductors of the above system.
4. A 2-wire circuit derived from two phases of a 3-phase system.
5. A 3-wire circuit derived from two phases and the neutral of a 3-phase WYE system. Common for supplying each apartment dwelling unit, with phases staggered among the various dwelling units throughout the complex.

In general, a 208V load built for the US Market, is meant to run off a circuit of either type 4 or 5, described above (usually type 5), which is exactly as you described in your OP. Where you could run into trouble, is if you were using a (usually 240V) load built for the rest-of-world, where it "expects" that one of its supply conductors is the neutral. 230/400V wye systems or something similar, is common for the rest of the world, so a device with a nominal voltage from 220V to 240V built for the rest-of-world, is likely meant to be wired phase-to-neutral, unless it is built to be indifferent to this issue.
 
Carultch said:
4. A 2-wire circuit derived from two phases of a 3-phase system.
5. A 3-wire circuit derived from two phases and the neutral of a 3-phase WYE system. Common for supplying each apartment dwelling unit, with phases staggered among the various dwelling units throughout the complex.
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We call 4 & 5 it 208 'open Wye' around here.

winnie said:
Question back to the original poster: is this equipment specifically designed and sold for the North American market, or is it something designed for a different market and then imported?
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If it is foreign it wont say 208 on it as the US and Canada were the first and are the last places using 208.
winnie said:
If you are talking a foreign import, then anything is possible and you need to be extra careful double checking that the system is compatible. You need to figure out what the equipment was really intended to use, and then see if what is available in North America actually matches in the relevant particulars.

-Jon
Click to expand...
Sage advice there.
 
Carultch said:
5. A 3-wire circuit derived from two phases and the neutral of a 3-phase WYE system. Common for supplying each apartment dwelling unit, with phases staggered among the various dwelling units throughout the complex.
Click to expand...

I've been promoting 'psingle phase' for #5.
 
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