Dual Phase

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Besoeker3

Besoeker3

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Retired Electrical Engineer
"Dual phase — alternately known as split phase — is basically the same thing as single phase. Dual phase consists of an Alternating Current (AC) with two wires. In the United States, the typical power setup in households consists of two 120 V power wires — a phase A and a phase B, which are out of phase by 180 degrees."

From Google., not just me.................:)
 
120-0-120 from a center tapped transformer is single phase.
120-0-120 which is neutral and two hots from a three phase wye source is NOT single phase and the line to line voltage is 208 volts. These two neutral to hot voltages are 120 (not 60) degrees out of phase and can be used to create the third hot to neutral leg to make full three phase.
This 2 of 3 situation can be used to feed a single phase panel.but that does not make it single phase.
A three wire MWBC from this panel will always have current on the neutral unless only 208V loads are connected. Which is not really an MWBC.

Sent from my Pixel 4a using Tapatalk
 
Besoeker3 said:
"Dual phase

From Google., not just me.................:)
Click to expand...
But not a standard term in the electrical industry in the US.

It has been a few years, but I do not recall ever seeing this term used in a electrical power systems textbook or professional paper.
 
Just because a word or phrase is in the dictionary doesn’t mean people use it.

For example we all call this # a “hash tag”, right? There is another word for it in the dictionary, an “octothorp”. Has ANYONE EVER hear another person use the term octothorp?
 
GoldDigger said:
120-0-120 from a center tapped transformer is single phase.
120-0-120 which is neutral and two hots from a three phase wye source is NOT single phase and the line to line voltage is 208 volts. These two neutral to hot voltages are 120 (not 60) degrees out of phase and can be used to create the third hot to neutral leg to make full three phase.
This 2 of 3 situation can be used to feed a single phase panel.but that does not make it single phase.
A three wire MWBC from this panel will always have current on the neutral unless only 208V loads are connected. Which is not really an MWBC.

Sent from my Pixel 4a using Tapatalk
Click to expand...
That's exactly as I see it Mr GoldDigger. I appreciate your clarity on this point.
 
GoldDigger said:
120-0-120 from a center tapped transformer is single phase.
120-0-120 which is neutral and two hots from a three phase wye source is NOT single phase and the line to line voltage is 208 volts. These two neutral to hot voltages are 120 (not 60) degrees out of phase and can be used to create the third hot to neutral leg to make full three phase.
This 2 of 3 situation can be used to feed a single phase panel.but that does not make it single phase.
A three wire MWBC from this panel will always have current on the neutral unless only 208V loads are connected. Which is not really an MWBC.

Sent from my Pixel 4a using Tapatalk
Click to expand...
The ANSI standards consider it single phase, that is good enough for me.
 
Jraef said:
Just because a word or phrase is in the dictionary doesn’t mean people use it.

For example we all call this # a “hash tag”, right? There is another word for it in the dictionary, an “octothorp”. Has ANYONE EVER hear another person use the term octothorp?
Click to expand...
Nope. Just the number sign.
 
Center-tapping a secondary doesn't change anything except available voltages. It's still only single-phase.

Looking at either line from the neutral point exhibits a difference of polarity, as we debated a while back.
 
Jraef said:
Just because a word or phrase is in the dictionary doesn’t mean people use it.

For example we all call this # a “hash tag”, right? There is another word for it in the dictionary, an “octothorp”. Has ANYONE EVER hear another person use the term octothorp?
Click to expand...
No, but I have used it myself on occasion. Only I spell it "octothorpe".
FWIW, some dictionary entries cite the first known use in 1971, so it is not one of those archaic Old English words.
 
Besoeker3 said:
"Dual phase — alternately known as split phase — is basically the same thing as single phase. Dual phase consists of an Alternating Current (AC) with two wires. In the United States, the typical power setup in households consists of two 120 V power wires — a phase A and a phase B, which are out of phase by 180 degrees."

From Google., not just me.................:)
Click to expand...
Note that for me in the US all of the first page entries for "dual phase" refer to dual-phase steels. I have to Google "dual phase power" to get the entry you cite. And it absolutely cannot, under current NEC, consist of TWO wires. The neutral wire must also be present at the service.
I suppose the article does not consider the neutral to be a "power" wire, but just try delivering power at 120V without it.
The description much more commonly used in the US is split-phase. (Split by the neutral?)
 
Jraef said:
Just because a word or phrase is in the dictionary doesn’t mean people use it.

For example we all call this # a “hash tag”, right? There is another word for it in the dictionary, an “octothorp”. Has ANYONE EVER hear another person use the term octothorp?
Click to expand...
Before hash tag that was usually called pound sign.
 
Jraef said:
... we all call this # a “hash tag”, right? There is another word for it in the dictionary, an “octothorpe”. [sp] Has ANYONE EVER hear another person use the term octothorpe?
Click to expand...
Yes. Ham radio, autopatch, touch tones, phone phreaking, DTMF.

I've also heard it (mistakenly) called an "octophobe".

octothorpe - Everything2.com

Ralph Carlsen explains the origin of the word octothorpe (or octothorp) in his note to the Telecom Digest journal. The word was invented in the 1960s by...
everything2.com everything2.com
 
GoldDigger said:
No, but I have used it myself on occasion. Only I spell it "octothorpe".
FWIW, some dictionary entries cite the first known use in 1971, so it is not one of those archaic Old English words.
Click to expand...
I typed that on my phone, IOS corrected it to remove the "e" at the end.

Long live our Apple overlords!.
 
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