Hello, I want to install new circuits in my basement and I want to do
it off of an electrical sub panel. The subs i see are only 1 phase.
How to I tap into the main box? Do i still use a double pole
breaker? Single pole breakers only go upto 30 amps. I want to run 4
separate circuits off the new box. Thanks.

On Jan 30, 3:52 am, wrote:
Hello, I want to install new circuits in my basement and I want to do
it off of an electrical sub panel. The subs i see are only 1 phase.
How to I tap into the main box? Do i still use a double pole
breaker? Single pole breakers only go upto 30 amps. I want to run 4
separate circuits off the new box. Thanks.

I had the same idea to power a tankless water heater but found it
better for My place to upgrade to a larger,higher amp panel..
Members here might need more info as to what Your existing set-up
is to give You the best help;;What amp is the main in Your box? Is the
existing panel full or are there unused circuits? Are You adding 15
amp circuits? 20 amp? larger? What amp is the service from the meter
outdoors? Do You have specific uses in mind for the new circuits so
the amp draw can be estimated or just general use?
I'm not a Sparkie but am interested after My recent upgrades..
Dean

As Dean said, you need to furnish a lot more info. When you say that subs
you see are only 1 phase, you're correct, it's rare for a residential
service to have 3 phase. Are you looking to connect a machine that requires
3 phase or just not familiar with the terminology? You will need to know the
size of the existing service and some idea of what's attached to it
currently. You'll also need to provide details of what you're looking to
connect in the basement, to determine the feeder and panel size. BTW single
pole breakers do come in larger than 30 amp, however its usually more
practical to build the device to operate at 240 volt and keep the amperage
lower



wrote in message
oups.com...
Hello, I want to install new circuits in my basement and I want to do
it off of an electrical sub panel. The subs i see are only 1 phase.
How to I tap into the main box? Do i still use a double pole
breaker? Single pole breakers only go upto 30 amps. I want to run 4
separate circuits off the new box. Thanks.

On Jan 30, 1:52 am, wrote:
Hello, I want to install new circuits in my basement and I want to do
it off of an electrical sub panel. The subs i see are only 1 phase.
How to I tap into the main box? Do i still use a double pole
breaker? Single pole breakers only go upto 30 amps. I want to run 4
separate circuits off the new box. Thanks.


OP-

I believe you mean "legs" ..........or do you really mean
phases...????

I suggest using a Square D QO Load Center..the one I'm thinking of has
8 breaker slots (100 or 125 amp rating; I think) & is feed 220V ( 2
legs) via a double pole breaker from the main.

Now you have sub panel that is mini version of your main...two legs,
across which you have 220V when you use a double pole breaker.

If you really mean phases & you're trying to get 3 phase power out of
a residential service you're sol unless you buy a phase converter.


but I'm pretty sure the first part of my answer will get the job done
for you, since it seems like you're just looking for more amps for a
heavier drawing load....and the way to get that is on a 220v circuit.

cheers
Bob

On 30 Jan 2007 01:52:21 -0800, wrote:

Hello, I want to install new circuits in my basement and I want to do
it off of an electrical sub panel. The subs i see are only 1 phase.
How to I tap into the main box? Do i still use a double pole
breaker? Single pole breakers only go upto 30 amps. I want to run 4
separate circuits off the new box. Thanks.


When I meet up with a person who wants put in a sub, I quickly ask
why?

There might be better solutions. Now since you said you want more
circuits, has a service calc been done?

tom @ www.BlankHelp.com

On Tue, 30 Jan 2007 11:41:30 -0500, wrote:

On 30 Jan 2007 01:52:21 -0800, wrote:

Hello, I want to install new circuits in my basement and I want to do
it off of an electrical sub panel. The subs i see are only 1 phase.
How to I tap into the main box? Do i still use a double pole
breaker? Single pole breakers only go upto 30 amps. I want to run 4
separate circuits off the new box. Thanks.


Actually most sub panels do use 2 hot legs (240v and 120v),
don't confuse that with the term, "single phase". That is really one
"phase", center tapped to give you two 120v circuits.

It can be one phase or two, depending on your reference point.
However, either way it's not three.

You use a 2 pole breaker in the main panel and be sure to run a 4 wire
feeder to the sub. Buy the extra ground bus kit. Leave the bonding
screw off the neutral bar, connected to the white wire in the fereder
and it stays insulated. The bare/green wire in the feeder goes to the
supplimental bar and that is where your ground wires go.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

Step one: For just 4 circuits, you'd be better off just home running all 4
back to the main panel. Lots less hassle and discussion. If you're out of
room on the main panel, then put the sub panel right next to the main and
see step one.

--
Steve Barker


wrote in message
oups.com...
Hello, I want to install new circuits in my basement and I want to do
it off of an electrical sub panel. The subs i see are only 1 phase.
How to I tap into the main box? Do i still use a double pole
breaker? Single pole breakers only go upto 30 amps. I want to run 4
separate circuits off the new box. Thanks.

On Tue, 30 Jan 2007 21:01:59 -0500, wrote:

On Tue, 30 Jan 2007 13:54:52 -0600, Mark Lloyd
wrote:

Actually most sub panels do use 2 hot legs (240v and 120v),
don't confuse that with the term, "single phase". That is really one
"phase", center tapped to give you two 120v circuits.

It can be one phase or two, depending on your reference point.
However, either way it's not three.

This is still singe phase. The fact that it is center tapped does not
add a phase.

Making that center tap the reference point (which seems logical since
it's grounded) and examining the voltages on the other 2 conductors,
you now have 2 points out of phase with other. 2 phases.

I even looked up the definition of "phase" again. Nothing about it
excludes 180-degree separation.

"Two phase" does exist but most people will never see it.
That has the phases shifted by 90 degrees and uses 4 circuit
conductors..

I haven't really seen it, but have read about it.

That's definitely 2 phase. That does not limit "2 phase" to that. That
would be like saying that the definition of "money" is "$15" (allowing
no other amounts to qualify).

There's also 4-phase, and I have seen that but only for driving
stepper motors.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

On Jan 30, 7:09 pm, Mark Lloyd wrote:
On Tue, 30 Jan 2007 21:01:59 -0500, wrote:
On Tue, 30 Jan 2007 13:54:52 -0600, Mark Lloyd
wrote:

Actually most sub panels do use 2 hot legs (240v and 120v),
don't confuse that with the term, "single phase". That is really one
"phase", center tapped to give you two 120v circuits.

It can be one phase or two, depending on your reference point.
However, either way it's not three.

This is still singe phase. The fact that it is center tapped does not
add a phase.

Making that center tap the reference point (which seems logical since
it's grounded) and examining the voltages on the other 2 conductors,
you now have 2 points out of phase with other. 2 phases.

I even looked up the definition of "phase" again. Nothing about it
excludes 180-degree separation.

"Two phase" does exist but most people will never see it.
That has the phases shifted by 90 degrees and uses 4 circuit
conductors..

I haven't really seen it, but have read about it.

That's definitely 2 phase. That does not limit "2 phase" to that. That
would be like saying that the definition of "money" is "$15" (allowing
no other amounts to qualify).

There's also 4-phase, and I have seen that but only for driving
stepper motors.
--
Mark Lloydhttp://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore,
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

As previously posted 2 phase power is very rare now days. Typical
service panels are a 3 wire single phase system. It is very common to
incorrectly refer to this as "two phase". Follow the link for an
explanation. http://en.wikipedia.org/wiki/Split_phase

On 30 Jan 2007 22:31:27 -0800, "Eric9822"
wrote:

On Jan 30, 7:09 pm, Mark Lloyd wrote:
On Tue, 30 Jan 2007 21:01:59 -0500, wrote:
On Tue, 30 Jan 2007 13:54:52 -0600, Mark Lloyd
wrote:

Actually most sub panels do use 2 hot legs (240v and 120v),
don't confuse that with the term, "single phase". That is really one
"phase", center tapped to give you two 120v circuits.

It can be one phase or two, depending on your reference point.
However, either way it's not three.

This is still singe phase. The fact that it is center tapped does not
add a phase.

Making that center tap the reference point (which seems logical since
it's grounded) and examining the voltages on the other 2 conductors,
you now have 2 points out of phase with other. 2 phases.

I even looked up the definition of "phase" again. Nothing about it
excludes 180-degree separation.

"Two phase" does exist but most people will never see it.
That has the phases shifted by 90 degrees and uses 4 circuit
conductors..

I haven't really seen it, but have read about it.

That's definitely 2 phase. That does not limit "2 phase" to that. That
would be like saying that the definition of "money" is "$15" (allowing
no other amounts to qualify).

There's also 4-phase, and I have seen that but only for driving
stepper motors.

As previously posted 2 phase power is very rare now days.

Leaving out the important words that you are referring to a PARTICULAR
2-phase system.

Typical
service panels are a 3 wire single phase system. It is very common to
incorrectly refer to this as "two phase". Follow the link for an
explanation. http://en.wikipedia.org/wiki/Split_phase

That does SAY that, but fails to consider that the word "phase"
already has a meaning.

BTW, what definition of "phase" are you using?

I'm noticing the parts of my post that you ignored.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

On Wed, 31 Jan 2007 23:11:50 -0500, wrote:


service panels are a 3 wire single phase system. It is very common to
incorrectly refer to this as "two phase". Follow the link for an
explanation. http://en.wikipedia.org/wiki/Split_phase

That does SAY that, but fails to consider that the word "phase"
already has a meaning.

BTW, what definition of "phase" are you using?


I suppose you can call single phase AC two phase you want but it will
only tag you as an amateur around electrical professionals.

Of course it has NOTHING to do with what I want. It has to do with
what the WORD "phase" actually means.

BTW, I never said I don't call it "split phase". I just said it was 2
phase also.

Just to be sure we're still talking about the same thing, it's AC from
a center-tapped transformer secondary with the center tap grounded?

Are you using a definition of "phase" that DOESN'T apply to the
120/240VAC electrical system? What it that definition?

BTW, here is one definition:

************************************************** *******

3. A measure of how far some cyclic behavior, such as wave motion,
has proceeded through its cycle, measured in degrees or radians. At
the beginning of the phase, its value is zero; at one quarter of its
cycle, its phase is 90 degrees (?/2 radians); halfway through the
cycle its value is 180 degrees (? radians), and so on. ? The phase
angle between two waves is a measure of their difference in phase. Two
waves of the same frequency that are perfectly in phase have phase
angle zero; if one wave is ahead of the other by a quarter cycle, its
phase angle 90 degrees (?/2 radians); waves that are perfectly out of
phase have phase angle 180 degrees (? radians), and so on. See more at
wave.

************************************************** ********

Source: American Heritage Science Dictionary (c) 2002

Of course it's a lot easier to understand than to explain.

AC is definitely "cyclic behavior", and when you examine the 2
nongrounded conductors at he same time you see the cycle at 2
different points. You can measure the voltage between the HOT wires of
2 different 120V outlets (120V hot to neutral). You get either 0V or
240V. That's enough to tell you something's going on.

120V is not the same as 120V (measured at different outlets). What's
different about it?
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

All that sounds fine, however when you are referring to residential and
commercial electrical services in the US, they are generally referred to as
single phase and three phase



"Mark Lloyd" wrote in message
...
On Wed, 31 Jan 2007 23:11:50 -0500, wrote:


service panels are a 3 wire single phase system. It is very common to
incorrectly refer to this as "two phase". Follow the link for an
explanation. http://en.wikipedia.org/wiki/Split_phase

That does SAY that, but fails to consider that the word "phase"
already has a meaning.

BTW, what definition of "phase" are you using?


I suppose you can call single phase AC two phase you want but it will
only tag you as an amateur around electrical professionals.

Of course it has NOTHING to do with what I want. It has to do with
what the WORD "phase" actually means.

BTW, I never said I don't call it "split phase". I just said it was 2
phase also.

Just to be sure we're still talking about the same thing, it's AC from
a center-tapped transformer secondary with the center tap grounded?

Are you using a definition of "phase" that DOESN'T apply to the
120/240VAC electrical system? What it that definition?

BTW, here is one definition:

************************************************** *******

3. A measure of how far some cyclic behavior, such as wave motion,
has proceeded through its cycle, measured in degrees or radians. At
the beginning of the phase, its value is zero; at one quarter of its
cycle, its phase is 90 degrees (?/2 radians); halfway through the
cycle its value is 180 degrees (? radians), and so on. ? The phase
angle between two waves is a measure of their difference in phase. Two
waves of the same frequency that are perfectly in phase have phase
angle zero; if one wave is ahead of the other by a quarter cycle, its
phase angle 90 degrees (?/2 radians); waves that are perfectly out of
phase have phase angle 180 degrees (? radians), and so on. See more at
wave.

************************************************** ********

Source: American Heritage Science Dictionary (c) 2002

Of course it's a lot easier to understand than to explain.

AC is definitely "cyclic behavior", and when you examine the 2
nongrounded conductors at he same time you see the cycle at 2
different points. You can measure the voltage between the HOT wires of
2 different 120V outlets (120V hot to neutral). You get either 0V or
240V. That's enough to tell you something's going on.

120V is not the same as 120V (measured at different outlets). What's
different about it?
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

On Thu, 1 Feb 2007 16:36:55 -0500, "RBM" rbm2(remove
wrote:

All that sounds fine, however when you are referring to residential and
commercial electrical services in the US, they are generally referred to as
single phase and three phase


Yes they are. I was never arguing about that.



"Mark Lloyd" wrote in message
.. .
On Wed, 31 Jan 2007 23:11:50 -0500, wrote:


service panels are a 3 wire single phase system. It is very common to
incorrectly refer to this as "two phase". Follow the link for an
explanation. http://en.wikipedia.org/wiki/Split_phase

That does SAY that, but fails to consider that the word "phase"
already has a meaning.

BTW, what definition of "phase" are you using?


I suppose you can call single phase AC two phase you want but it will
only tag you as an amateur around electrical professionals.

Of course it has NOTHING to do with what I want. It has to do with
what the WORD "phase" actually means.

BTW, I never said I don't call it "split phase". I just said it was 2
phase also.

Just to be sure we're still talking about the same thing, it's AC from
a center-tapped transformer secondary with the center tap grounded?

Are you using a definition of "phase" that DOESN'T apply to the
120/240VAC electrical system? What it that definition?

BTW, here is one definition:

************************************************** *******

3. A measure of how far some cyclic behavior, such as wave motion,
has proceeded through its cycle, measured in degrees or radians. At
the beginning of the phase, its value is zero; at one quarter of its
cycle, its phase is 90 degrees (?/2 radians); halfway through the
cycle its value is 180 degrees (? radians), and so on. ? The phase
angle between two waves is a measure of their difference in phase. Two
waves of the same frequency that are perfectly in phase have phase
angle zero; if one wave is ahead of the other by a quarter cycle, its
phase angle 90 degrees (?/2 radians); waves that are perfectly out of
phase have phase angle 180 degrees (? radians), and so on. See more at
wave.

************************************************** ********

Source: American Heritage Science Dictionary (c) 2002

Of course it's a lot easier to understand than to explain.

AC is definitely "cyclic behavior", and when you examine the 2
nongrounded conductors at he same time you see the cycle at 2
different points. You can measure the voltage between the HOT wires of
2 different 120V outlets (120V hot to neutral). You get either 0V or
240V. That's enough to tell you something's going on.

120V is not the same as 120V (measured at different outlets). What's
different about it?
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

"Mark Lloyd" wrote in message
...
On Thu, 1 Feb 2007 16:36:55 -0500, "RBM" rbm2(remove
wrote:

All that sounds fine, however when you are referring to residential and
commercial electrical services in the US, they are generally referred to
as
single phase and three phase


Yes they are. I was never arguing about that.

I think the main problem may be that there is also a "two phase" power
system which uses two phases separated by 90 degrees. It is no longer common
in power distribution as it has been replaced by 3 phase systems but is
still used in specialized applications.

The center tapped system is included in the category of "single phase power"
but you do hear even electricians refer to "the other phase" or "the
opposite phase". It is even weirder when you have a three phase delta system
with one side center-tapped and grounded. It is one of those unfortunately
ambigious situations where the language is sometimes not precise enough to
clearly describe the situation. People have been disagreeing and arguing
this point forever and probably will continue forever. It is not a
disagreement about the facts, but only "What is the nameof it?".

Don Young


"Mark Lloyd" wrote in message
. ..
On Wed, 31 Jan 2007 23:11:50 -0500, wrote:


service panels are a 3 wire single phase system. It is very common to
incorrectly refer to this as "two phase". Follow the link for an
explanation. http://en.wikipedia.org/wiki/Split_phase

That does SAY that, but fails to consider that the word "phase"
already has a meaning.

BTW, what definition of "phase" are you using?


I suppose you can call single phase AC two phase you want but it will
only tag you as an amateur around electrical professionals.

Of course it has NOTHING to do with what I want. It has to do with
what the WORD "phase" actually means.

BTW, I never said I don't call it "split phase". I just said it was 2
phase also.

Just to be sure we're still talking about the same thing, it's AC from
a center-tapped transformer secondary with the center tap grounded?

Are you using a definition of "phase" that DOESN'T apply to the
120/240VAC electrical system? What it that definition?

BTW, here is one definition:

************************************************** *******

3. A measure of how far some cyclic behavior, such as wave motion,
has proceeded through its cycle, measured in degrees or radians. At
the beginning of the phase, its value is zero; at one quarter of its
cycle, its phase is 90 degrees (?/2 radians); halfway through the
cycle its value is 180 degrees (? radians), and so on. ? The phase
angle between two waves is a measure of their difference in phase. Two
waves of the same frequency that are perfectly in phase have phase
angle zero; if one wave is ahead of the other by a quarter cycle, its
phase angle 90 degrees (?/2 radians); waves that are perfectly out of
phase have phase angle 180 degrees (? radians), and so on. See more at
wave.

************************************************** ********

Source: American Heritage Science Dictionary (c) 2002

Of course it's a lot easier to understand than to explain.

AC is definitely "cyclic behavior", and when you examine the 2
nongrounded conductors at he same time you see the cycle at 2
different points. You can measure the voltage between the HOT wires of
2 different 120V outlets (120V hot to neutral). You get either 0V or
240V. That's enough to tell you something's going on.

120V is not the same as 120V (measured at different outlets). What's
different about it?
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

On Thu, 01 Feb 2007 22:07:32 -0500, wrote:

On Thu, 01 Feb 2007 12:39:16 -0600, Mark Lloyd
wrote:

On Wed, 31 Jan 2007 23:11:50 -0500, wrote:


Just to be sure we're still talking about the same thing, it's AC from
a center-tapped transformer secondary with the center tap grounded?

Are you using a definition of "phase" that DOESN'T apply to the
120/240VAC electrical system? What it that definition?

There is only one secondary winding so it is single phase. The center
tap does not change that.

Yes, there is one winding. That doesn't keep the reference point (for
measuring voltages) from being in the middle (center tap), and
different phases being measurable depending on which end of that
winding you measure at.

The center tap is actually in the center, meaning the voltage will be
the same which ever end you measure. What is different if not phase?
If nothing was different, you could put a wire between those points
(the ends of the winding) and have no current flow (so your 240V
appliances couldn't be working).
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

On Thu, 1 Feb 2007 21:49:38 -0600, "Don Young"
wrote:


"Mark Lloyd" wrote in message
.. .
On Thu, 1 Feb 2007 16:36:55 -0500, "RBM" rbm2(remove
wrote:

All that sounds fine, however when you are referring to residential and
commercial electrical services in the US, they are generally referred to
as
single phase and three phase


Yes they are. I was never arguing about that.

I think the main problem may be that there is also a "two phase" power
system which uses two phases separated by 90 degrees. It is no longer common
in power distribution as it has been replaced by 3 phase systems but is
still used in specialized applications.

The center tapped system is included in the category of "single phase power"
but you do hear even electricians refer to "the other phase" or "the
opposite phase". It is even weirder when you have a three phase delta system
with one side center-tapped and grounded. It is one of those unfortunately
ambigious situations where the language is sometimes not precise enough to
clearly describe the situation. People have been disagreeing and arguing
this point forever and probably will continue forever. It is not a
disagreement about the facts, but only "What is the nameof it?".

Don Young

Right.

I'd find that 3-phase delta system confusing too.



"Mark Lloyd" wrote in message
...
On Wed, 31 Jan 2007 23:11:50 -0500, wrote:


service panels are a 3 wire single phase system. It is very common to
incorrectly refer to this as "two phase". Follow the link for an
explanation. http://en.wikipedia.org/wiki/Split_phase

That does SAY that, but fails to consider that the word "phase"
already has a meaning.

BTW, what definition of "phase" are you using?


I suppose you can call single phase AC two phase you want but it will
only tag you as an amateur around electrical professionals.

Of course it has NOTHING to do with what I want. It has to do with
what the WORD "phase" actually means.

BTW, I never said I don't call it "split phase". I just said it was 2
phase also.

Just to be sure we're still talking about the same thing, it's AC from
a center-tapped transformer secondary with the center tap grounded?

Are you using a definition of "phase" that DOESN'T apply to the
120/240VAC electrical system? What it that definition?

BTW, here is one definition:

************************************************** *******

3. A measure of how far some cyclic behavior, such as wave motion,
has proceeded through its cycle, measured in degrees or radians. At
the beginning of the phase, its value is zero; at one quarter of its
cycle, its phase is 90 degrees (?/2 radians); halfway through the
cycle its value is 180 degrees (? radians), and so on. ? The phase
angle between two waves is a measure of their difference in phase. Two
waves of the same frequency that are perfectly in phase have phase
angle zero; if one wave is ahead of the other by a quarter cycle, its
phase angle 90 degrees (?/2 radians); waves that are perfectly out of
phase have phase angle 180 degrees (? radians), and so on. See more at
wave.

************************************************** ********

Source: American Heritage Science Dictionary (c) 2002

Of course it's a lot easier to understand than to explain.

AC is definitely "cyclic behavior", and when you examine the 2
nongrounded conductors at he same time you see the cycle at 2
different points. You can measure the voltage between the HOT wires of
2 different 120V outlets (120V hot to neutral). You get either 0V or
240V. That's enough to tell you something's going on.

120V is not the same as 120V (measured at different outlets). What's
different about it?
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

wrote in message
...
On Fri, 02 Feb 2007 15:13:46 -0600, Mark Lloyd
wrote:

. It is even weirder when you have a three phase delta system
with one side center-tapped and grounded. It is one of those
unfortunately
ambigious situations where the language is sometimes not precise enough
to
clearly describe the situation. People have been disagreeing and arguing
this point forever and probably will continue forever. It is not a
disagreement about the facts, but only "What is the nameof it?".

Don Young

Right.

I'd find that 3-phase delta system confusing too.


It is just a garden variety single phase 120/240 transformer that they
add a second one to and trick motors into thinking it is 3 phase.
Generally they don't use the 3d transformer to make a true delta.
If they wanted to spend that much money you would get 3p wye.
You see it in light industrial areas where most of the load is single
phase on a big 1p transformer and a second only supplies the "red" leg
for the 3p load. (actually identified orange) As long as you never put
L/N loads on the 208v red leg it works fine.
I have seen a lot of the two transformer open delta and three transformer
wye services, but I have also seen quite a few three transformer closed
delta systems. It seems to depend on the relative loads. The open delta
seems to be used where the three phase load is fairly light and the closed
delta where there is a heavy three phase load but 120/240 single phase
service is also required. It may be a regional thing and I think the delta
connection is becoming rarer and is being replaced with a separate single
phase transformer where 120/240 is required.

Don Young

Don Young wrote:

wrote in message
...

On Fri, 02 Feb 2007 15:13:46 -0600, Mark Lloyd
wrote:


. It is even weirder when you have a three phase delta system

with one side center-tapped and grounded. It is one of those
unfortunately
ambigious situations where the language is sometimes not precise enough
to
clearly describe the situation. People have been disagreeing and arguing
this point forever and probably will continue forever. It is not a
disagreement about the facts, but only "What is the nameof it?".

Don Young

Right.

I'd find that 3-phase delta system confusing too.


It is just a garden variety single phase 120/240 transformer that they
add a second one to and trick motors into thinking it is 3 phase.
Generally they don't use the 3d transformer to make a true delta.
If they wanted to spend that much money you would get 3p wye.
You see it in light industrial areas where most of the load is single
phase on a big 1p transformer and a second only supplies the "red" leg
for the 3p load. (actually identified orange) As long as you never put
L/N loads on the 208v red leg it works fine.

I have seen a lot of the two transformer open delta and three transformer
wye services, but I have also seen quite a few three transformer closed
delta systems. It seems to depend on the relative loads. The open delta
seems to be used where the three phase load is fairly light and the closed
delta where there is a heavy three phase load but 120/240 single phase
service is also required. It may be a regional thing and I think the delta
connection is becoming rarer and is being replaced with a separate single
phase transformer where 120/240 is required.

Open delta lowers the transformer power factor so the the transformers
have to be derated - probably why open delta is generally light loads.
Wye is easier to balance which is a good reason to use it instead of
delta. (You can also get wye with 2 transformers in a Scott or T
connection.)

--
bud--

On Fri, 02 Feb 2007 20:41:33 -0500, wrote:

On Fri, 02 Feb 2007 15:13:46 -0600, Mark Lloyd
wrote:

. It is even weirder when you have a three phase delta system
with one side center-tapped and grounded. It is one of those unfortunately
ambigious situations where the language is sometimes not precise enough to
clearly describe the situation. People have been disagreeing and arguing
this point forever and probably will continue forever. It is not a
disagreement about the facts, but only "What is the nameof it?".

Don Young

Right.

I'd find that 3-phase delta system confusing too.


It is just a garden variety single phase 120/240 transformer that they
add a second one to and trick motors into thinking it is 3 phase.
Generally they don't use the 3d transformer to make a true delta.
If they wanted to spend that much money you would get 3p wye.
You see it in light industrial areas where most of the load is single
phase on a big 1p transformer and a second only supplies the "red" leg
for the 3p load. (actually identified orange) As long as you never put
L/N loads on the 208v red leg it works fine.

That reminds me that there's a lot about 3-phase systems that I don't
know.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy