# Current in the neutral wire of 3 phase system

Discussion in 'Electrical | Electronics | Communications' started by avm, Jan 7, 2009.

1. ### avm Apprentice

When a 3 phase system is balanced, what will be the current in the neutral wire ?

#1
2. ### ashuashi Apprentice

Engineering Discipline:
Electrical
Practically there is no balanced 3 phase system. Ideally in 3 phase balanced system neutral current will be "ZERO".

regards,

#2
3. ### avm Apprentice

I was also of your opinion. But i have seen in a book that the neutral current in a three phase balanced system is one third of the phase current. that is why i posed the question.

#3
4. ### ashuashi Apprentice

Engineering Discipline:
Electrical
This case is for Star connection & delta connection when Line current & Phase current come into picture.

Check for phase current & Line current details. Your doubt will be resolved.

#4
5. ### sauravgoswami Rookie

Engineering Discipline:
Electrical & Electronics
first of all nuetral point is a null point,though it not an ground ,well theoritacally it should be ZERO,but practically its not possible so watever network you are considering you should try to keep it close to zero.

#5
6. ### laxman7m Newbie

Ideally, the current in the neutral wire is ZERO

#6
7. ### ashuashi Apprentice

Engineering Discipline:
Electrical

#7
8. ### avm Apprentice

Thank u all who have contributed to the discussion...............................

#8
9. ### baja Apprentice

Engineering Discipline:
Electrical & Electronics
Neutral carries sum of three currents.
In a 3 ph system currents whose magnitude and angle are
1. I (0)
2. I (120)
3. I (240)

if we add all three we get zero..

#9
10. ### manoj_2all Apprentice

Engineering Discipline:
Electrical
Neutral is the point at which all the three phase’s current meets and the algebraic sum of current becomes zero in case of “Balanced Load Condition”.

I = I1 + I2 + I3 = 0

When ALL phase has balanced load, neutral should be ZERO volt in respect to earth. Be careful the word “Balanced”, which means, if there is an unbalanced phased (due to load), the neutral will no longer be ZERO volt in respect to earth. When there is more than ZERO volt between neutral and earth, then there will be current flow through these 2 points (Leakage Current).

Even for most of the time, neutral and earth has ZERO volt between them; they should never be connected together or be used interchangeably.

Neutral: Return path of current flow in order to make a closed circuit [Return Path Conductor].

Earth: Path for Leakage current [Short Circuit / Fault Current / Crack in Insulation] in the circuit to protect Human & Equipment Safety.

#10
11. ### QuarkToo Apprentice

zero and there is no need for a neutral wire if it is truly balanced. The neutral wire keeps voltage spikes from occurring in an unbalanced system. It is unlikely that you will find a balanced system in the real world.

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12. ### hetal prajapati Apprentice

nutral is only in star connection no nutral wire in delta am right?

#12
13. ### sasuke Apprentice

Engineering Discipline:
Electrical & Electronics
I [FONT=&quot]though Ineutral = I1 + I2 + I3. and not zero. should have current as neutral are return path of the phase current right? [/FONT]

#13
14. ### saurabh2486 Apprentice

Engineering Discipline:
Aerospace
theoretically it will be 0 but practically it will show readings close to 0 as there might be some losses

#14
15. ### prabim Newbie

Why excessive neutral current dot desirable in power distribution systems?

#15
16. ### debskolmodin Newbie

Engineering Discipline:
Aerospace
If 2 currents on phase A and B are 16 A and phase C is 10 A what is the current on the neutral? Thanks in advance for your help.

#16

Engineering Discipline:
Electrical & Electronics
i think it may be 4 or 8
because difference current flows in neutral to balance

#17
18. ### Arp Apprentice

Engineering Discipline:
Electrical
do the phasor sum of current not scalar

#18