220V outlet wiring

[faresos]

I'm working on a project overseas that the building will utilize 480V and 208V system. However, the client wants to provide a 220V outlets through out the facility just in case if they need to bring local tools which operates on 220V. I have two questions:

1. Does the tool care if the input voltage (220V) is line to neutral or line to line?
2. I have been looking to find a step down transformer (480V to 220V) or step up transformer (from 208V to 220V) but not having a good luck. Does any one know if there a such thing? The only thing I was able ti find is 230V, would 220V tool works on 230V?

Thanks in advance

 

[Besoeker]

I'm working on a project overseas that the building will utilize 480V and 208V system. However, the client wants to provide a 220V outlets through out the facility just in case if they need to bring local tools which operates on 220V. I have two questions:

1. Does the tool care if the input voltage (220V) is line to neutral or line to line?

Shouldn't.

2. I have been looking to find a step down transformer (480V to 220V) or step up transformer (from 208V to 220V) but not having a good luck. Does any one know if there a such thing?

You can get pretty much any ratio transformer built to order. If you want. We routinely do. If you go that route you need to tell the manufacturer things like frequency, expected ambient conditions, and type of enclosure (if any) required.

The only thing I was able ti find is 230V, would 220V tool works on 230V?

Probably but check supply frequency. It might matter.

Where overseas if you don't mind me asking?

 

[faresos]

south Korea

 

[Besoeker]

south Korea

Then 60Hz.
And local tools should be OK.
Have you checked on getting a 480V to 220V transformer made locally?
Obviously, it can be done.

 

[faresos]

Then 60Hz.
And local tools should be OK.
Have you checked on getting a 480V to 220V transformer made locally?
Obviously, it can be done.

Not really. My thought was most equipment will have a tolerance of 10% plus or minus then I could use 208V outlet which will have 5% less voltage variation.

 

[Besoeker]

Not really. My thought was most equipment will have a tolerance of 10% plus or minus then I could use 208V outlet which will have 5% less voltage variation.

Maybe a bit marginal.
220 less 10% is 198.0V
208 less 5% is 197.6.V

If it was my project, I'd get a transformer made to do the job.

 

[esobocinski]

My thought was most equipment will have a tolerance of 10% plus or minus then I could use 208V outlet which will have 5% less voltage variation.

Are you talking power tools, or "everything else" that gets brought into an office to support normal life?

Most appliances sold in South Korea (that don't have 60 Hz AC motors) are designed to also be sold in most of Europe without modification, so appliances are designed to be interoperable at 220 to 240 volts nominal. (The EU is nominally 230 volts, but intentionally specifies enough tolerance so that existing 220 and 240 volt systems in Europe are compliant). Meanwhile, 208 volts nominal isn't a primary voltage anywhere; it's only found as three-phase line-to-line in North America and a few small countries that copied us. You'd therefore be pretty sure that local appliances would work on 230 volts, not so sure on 208 volts. It's no accident that even the Type F sockets used in South Korea are the same as almost everywhere in mainland Europe.

Big disclaimer: I'm only passing on what I know; I'm completely uncertified to recommend anything in this situation.

Why can't you ask the client? It's their tools that get fried if there's a misunderstanding. I'd think you would want them to sign off on the solution anyway.

 

[blargh]

Originally Posted by faresos
I'm working on a project overseas that the building will utilize 480V and 208V system. However, the client wants to provide a 220V outlets through out the facility just in case if they need to bring local tools which operates on 220V. I have two questions:

1. Does the tool care if the input voltage (220V) is line to neutral or line to line?

​

Shouldn't.

On a related note, since I've had a similar situation lurking in the back of my mind: would a 220V L-N circuit require only one fuse (OCPD), with a 220V L-L circuit requiring two fuses?

 

[gareth0127]

only one fuse required L-N circuits but good practice to use double pole breaker

 

[gareth0127]

and yes L-L def needs one device in each phase

 

[kwired]

only one fuse required L-N circuits but good practice to use double pole breaker

Why? We have 277 volt L-N loads in many places in USA, Almost always just a single pole breaker.

400/230 systems found in other countries are the same thing with just a little lower voltage, and usually 50Hz frequency instead of 60.

 

[Joethemechanic]

I was wondering about breaking the neutral too. I really only have seen that in K & T installations.

I'm assuming a N-G bond?

 

[Dennis Alwon]

On a related note, since I've had a similar situation lurking in the back of my mind: would a 220V L-N circuit require only one fuse (OCPD), with a 220V L-L circuit requiring two fuses?

I think that two fuses would be non compliant in most cases, at least here in the US.

 

[jim dungar]

400/230 systems found in other countries are the same thing with just a little lower voltage, and usually 50Hz frequency instead of 60.

Nominal 400Y/230V 60Hz is becoming common in IT server rooms, now that so many power supplies accept voltages from 100 up to 240V. So I expect we will here more questions about 230V L-N.

 

[gareth0127]

Why? We have 277 volt L-N loads in many places in USA, Almost always just a single pole breaker.

400/230 systems found in other countries are the same thing with just a little lower voltage, and usually 50Hz frequency instead of 60.

Im basing this on my experience in UK oil refineries so maybe doesnt apply in most applications on this particular forum. Surely it is better to break all conductors in the event of a fault or during an isolation?

 

[blargh]

I think that two fuses would be non compliant in most cases, at least here in the US.

Why would that be? The situation I'm picturing is a machine with a 208Y/120 supply, with 100~240 VAC devices connected up L-L to keep current down and better balance the phase loads. I'd think that any ungrounded conductors would have to be fused.

 

[Twoskinsoneman]

Why would that be? The situation I'm picturing is a machine with a 208Y/120 supply, with 100~240 VAC devices connected up L-L to keep current down and better balance the phase loads. I'd think that any ungrounded conductors would have to be fused.

I believe his comment was directed at the two fuses for L-N circuits.

240.22 Grounded Conductor. No overcurrent device shall
be connected in series with any conductor that is intentionally
grounded, unless one of the following two conditions is met:
(1) The overcurrent device opens all conductors of the circuit,
including the grounded conductor, and is designed
so that no pole can operate independently.
(2) Where required by 430.36 or 430.37 for motor overload
protection.

 

[kwired]

Im basing this on my experience in UK oil refineries so maybe doesnt apply in most applications on this particular forum. Surely it is better to break all conductors in the event of a fault or during an isolation?

If you are talking hazardous locations then NEC does require simultaneous disconnection of grounded conductor in some locations. Does not require it for controls just disconnecting means.

You will find contactors marked something like "above 240 volts break all lines" - that is manufacturers instructions and not a general NEC requirement.