On Oct 28, 1:37*pm, "Steve N." wrote:
"JIMMIE" wrote in message

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On Oct 28, 12:49 pm, "Steve N." wrote:





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On Oct 27, 6:13 pm, "Steve N." wrote:

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On Oct 27, 3:16 pm, "Steve N." wrote:

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On Oct 27, 2:37 am, "Steve N." wrote:

"Steve N." wrote in message

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"JIMMIE" wrote in message
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On Oct 26, 10:37 pm, (Doug Miller) wrote:
In article , Sam E
wrote:
If all the loads supplied by that service are 120V loads (e.g.
blender,
toaster, light bulbs, range hood, stereo, TV, computer, etc.)
what
do
you get
when you divide that maximum power by 120V?

That would be 400A.

Exactly so.

Of course that's only in your imagination since
the math is invalid (120V is obtained by splitting the service
into
2
separate halves, each of which is only 24KW).

200A each. Total of 400A of 120V loads -- as you said.

Where in the box can you measure 400 amps? If the panel is
controlling
48KW there will be no current on the neutral because the currents
will
be balanced. The current that flows through one half of the
breaker
is
the same current that flows through the other half of the breaker.
In
this case what you have is two 200 amp breakers in series. Doug
you
have more current coming into the box than going out and that
shouldnt
happen.

The power is coming in from a transformer secondary winding that
is
center-tapped. Let's call the 3 wires
Line 1, the neutral & Line 2 (seee the link below that shows a
transformer
secondary at the bottom of the page). When you put 120V loads
across
Line
1 & neutral, they are independent of Line 2. In effect, you're
only
using
half of the transformer secondary, so you're only going thru the
Line
1
half of the main breaker. The current path is from the Line 1 side
of
the
secondary winding, thru the Line 1 side of the main breaker, thru
the
load, and back thru the neutral to the Line 1 half of the
secondary
winding.

Agree.

If you also put a 120V load across Line 2 and the neutral, then

the current path is from the Line 2 side of the secondary winding
thru
the
Line 2 side of the main breaker, thru the load, and back thru the
neutral
(in the opposite direction of current flow of the Line 1 current
thru
the
neutral) and back to the Line 2 side of the secondary winding.
Both
loads
form their own circular loops that are independent of each other,
except
for sharing the neutral (in opposite directions) to complete their
separate circuits.
Don't agree with this. If the second load on line 2 is equal to the
load already on line 1, then the current flow is in on line 1 and
back
out on line 2. No current flows in the neutral.

OK, you're right. If they're perfectly balanced. So lets make the Line
1-to-neutral load
a 200A load (0.6 ohms), and the Line 2-to-neutral load 199A (0.603
ohms).
Now we have an unbalanced current of
1 amp thru the neutral.So we have 200A thru one side of the breaker,
and
199A thru the other side. So what's the total amperage now?? Is it
200A
or
399A, or? It's all in how you look at it.

No, it not. Once again, the physical current in the service cable is
200 amps. You have 200 amps flowing IN on one hot, 199 flowing OUT
on the other hot and 1 amp flowing OUT on the neutral. The current
flowing in that circuit is 200 amps. You don't count current twice.

How much current is flowing in a simple 120W light bulb plugged into a
120Volt outlet? 1 amp. Now simply add another single wire in
parallel with one of those supplying the light bulb. The current
will be split now, with some part of it going via one wire, some via
the other. For sake of argument, let;s assume it just splits
evenly. So, now you have 1 amp coming in on one wire, 1/2 amp
leaving via one wire, 1/2 amp leaving via the second wire. How much
current is flowing in this "service" circuit to the light bulb?
There is no confusion, it's 1 amp.

It's a simple matter of applying Kirchoffs law.

In the end ,it's a matter of
total energy or kW.
200A x 120V=24000W & 199A x 120V= 23880W for a total of 47880W or
47.88kW

The key here is look at that service cable coming from the
transformer
and you have a circuit running a max of 200 amps. Agree?

With a perfectly balanced load - yes, one circuit. With a slightly
unbalanced load - then, two circuits.- Hide quoted text -

- Show quoted text -
Balanced or unbalanced matters not a wit. There is still a current
of 200 amps coming and going either way. The only difference balance
makes is which PATH that 200 amp current takes.

Umm...so you're saying that if you have a 200A load on Line1to neutral
that
you're going to have 200A going thru both sides of the 200A breaker
regardless of the load on the Line 2 to neutral side??

No, never said that.

What if you have a 200A load on the Line 1 to neutral side, and nothing
loading the Line 2 to neutral side? Are you still going to have 200A
going
thru each "leg" of the main breaker?- Hide quoted text -

- Show quoted text -
You're going to have 200A flowing from Line 1 to neutral. Again,
that is 200 amps flowing in the service cable. As I said, if it's
fully loaded, you will have a max of 200 amps flowing in the service
cable. That's 200 amps coming in, 200 amps going out. The only
difference is whether some of the current flows on the neutral or
not. If the neutral has some current, then one of the hot lines must
have less than 200 amps or you'd violate Kirchoff's law.

But you still didn't answer the question about the current flow path. If
you
have a 120V 200A load between Line 1 & neutral,and no load between Line 2
&
neutral, how much current flows thru the Line 1 side of the main breaker,
how much current flows thru the Line 2 side of the main breaker, and how
much thru the neutral?
There will be 0 amps in the neutral. The loads form two legs of a
balanced bridge, the windings in the transformer form the other two
legs, When they are balancedas you described therer will be ZERO
current in the neutral. Dont believe me check it for yourself. Make a
test circuit out of two 100 watt light bulbs connected in series, put
them across a 240VAC connection with no neutral connection then
connect the neutral between them. Measure the current in the neutral.
It will be ZERO. measure the current in each hot leg. The neutral is
only there to carry the difference between the two legs when there is
an imbalance. If the current in one leg was 100 amps and the the other
had 50 amps the neutral current would be 100 -50 + 50 amps.. When the
load is balanced and you measure the current in each leg you are just
measuring the same current twice.

Re-read the question. I'm asking about a SINGLE 120V 200A load between Line
1 & neutral, not 2 loads in series across 240V.- Hide quoted text -

- Show quoted text -

Doesnt matter if there is no current flow in the neutral, Quit trying
to reason what you dont understand and build a mock up circuit if this
really concerns you that much. I am growing very bored of talking to
people who are more interested in defending their argument than
actually trying to learn something. Any decent text that explains
Kerchov's(sp?) Law as applied to AC circuits will give you the answer.

Jimmie