# Three phase line currents

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#### mwdkmpr

##### Member
On a 208V three phase wye system all loads are 208V single phase. If A-B load is 200A and B-C load is 200A and there is no C-A load. What will the phase current on phase B be?

#### Smart \$

##### Esteemed Member
On a 208V three phase wye system all loads are 208V single phase. If A-B load is 200A and B-C load is 200A and there is no C-A load. What will the phase current on phase B be?
Depends on the loads' power factor, but for power factors of 1 or unity... 200A ? sqrt(3) = 346.4A.

PS: The C-A load is irrelevant.

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#### Phil Corso

##### Senior Member
Smart \$; Mwdkmpr?? Each of the 3-lines will carry current for the conditions cited in Smart \$?s post. Following is a solution using what I call the GiFiES (pronounced Jiffy?s) method, where: Gi => Given; Fi => Find; E => Equation(s); S => Solution

Given:
VAB=208∡+120
VBC=2080
VCA=208∡-120
And if PF = 1.0, or unity, then,
IAB=200∡+120
IBC=2000
ICA=0

Find:
Line-Currents, IA, IB, and IC

Equations:
IA = IAB ? ICA

IB = IBC ? IAB
IC = ICA ? IBC

Solutions
IA = 200120
IB = 346- 30
IC = 200180

Regards, Phil Corso

#### Smart \$

##### Esteemed Member
...

Equations:
IA = IAB ? ICA

IB = IBC ? IAB
IC = ICA ? IBC

Solutions
IA = 200120
IB = 346- 30
IC = 200180

Regards, Phil Corso
Looks good... but assumes the asker knows vector math. If they don't, the equations and solutions (i.e. results) look mighty confusing.

#### Phil Corso

##### Senior Member
Smart \$... you, of course, are right, that is, Line-B current is Sqrt(3) x 200A, and to solve the problem one must know complex math! The point of my answer was to identify of all three line-currrents!

Regards, Phil

#### mwdkmpr

##### Member
Thanks! Please, never grow weary of trying to educate us common folk

#### Phil Corso

##### Senior Member
Mwdkmpr... is it your supposition, then, that we uncommon folk should not use formulas? More importantly, were you enlightened (even a little)?

Phil

#### mwdkmpr

##### Member
Aw contraire, I find your fabulous formulations fascinating and electricaly enlightening!

#### Phil Corso

##### Senior Member
Mwdkmpr...
Are you interested in the formulas to use for a non-resitive load?
Phil

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