why fuse is not used in neutral...
Answers were Sorted based on User's Feedback
Answer / suresh
Fuse is used to protect the equipment from abnormal
condition, equipment or load is always connectected before
the nuetral point,flow of current is from phase to neutral,
so there will be no use to connect the fuse on the nuetral
side.nuetral side current value is zero.
Is This Answer Correct ? | 77 Yes | 17 No |
Answer / mangesh salunkhe
neutral comes in star connected systems. As per kirchoffs
current theorem current comming at any junction is curent
going out from that junction. if we apply this law in star
connected systems we could find out that under normal
condiations current flowing in neutral is zero 0. in such
systems many a times neutral is connected as neutral path.
under normal conditions with rated voltage, pf equipment
draws rated current and consumes. hence we could find that
for balanced systems in neutral there is zero current. But,
under fault conditions (e.g. phase to ground fault at
equipment end) the current drawn from system is several
times than rated. this high current drawn from phase
conductors. if we allow this current to flow our system is
already damged but we also damages other networs connected.
hence to stop this current in short curcuit conditions we
use fuse in phase. once supply is disconnected thers no use
disconneting neutral!
Is This Answer Correct ? | 12 Yes | 6 No |
Answer / sankar
then why in dc fuses are used in both positive and negative..
Is This Answer Correct ? | 7 Yes | 3 No |
Answer / sowmya
Neutral is grounded one so there is no need connect the fuse to the neutral.
Is This Answer Correct ? | 8 Yes | 4 No |
Answer / stm619
In addition to above , also pls note the following
if the fuse is placed in neutral, because the circuit can complete or obtain a conduction pathway either by the neutral or earth. For a condition which have a fuse placed in neutral can only disconnect for an excess current which is completed through the neutral only. So the circuit result in non disconnection, if the current flows through earth or if there any electric shock, which is also a conduction through phase and earth. But for a fuse connected in phase, for any conduction path the complete current flows only through the fuse, as it is the current source.
And a fuse should can completely disconnect the circuit or it can isolate the load and wiring from the live supply source by its burn off or remove. Since neutral is not a live conductor coming from the source, disconnecting a neutral line can only open the circuit and prevents the current flow, but the live phase carries a potential and always provides a live supply at the conductors or to the load. Also during a maintenance or repair the current carrying conductors cannot be isolated by taking out the fuse.
Thus fuse connected in phase can provide all over protection and So for safety reason, a fuse should not be used in the neutral.
Is This Answer Correct ? | 5 Yes | 2 No |
Answer / tushar gawas
as the supply is alternating in nature,hence if anyone
return path gets disconnected under fault condition the
supply gets disconnected.since phase carries vtg which
melts fuse element under fault condition so fuse is used in
phase.
Is This Answer Correct ? | 7 Yes | 5 No |
Answer / jetho balani
fuse is used to isolate the supply source, since neutral is not LIVE conductor coming from the source so it is not required to isolate in case of any kind of fault, therefore fuse is not used in neutral
In DC Source both +ve & -ve terminals are LIVE therefore fuse is used in both
Is This Answer Correct ? | 5 Yes | 3 No |
Answer / shimbhu singh
Kyonki yah puri dharma wahn nhi kar salta or yah niyam keep virudh bhi h
Is This Answer Correct ? | 2 Yes | 2 No |
Answer / avs
The main function of fuse is to prevent continuous flow of faulty current through the system. Whenever there is an over current flowing through the fuse element for a certain period of time, the fuse element melts and disconnects the circuit to prevent continuous flow of faulty current. Hence it is desirable to flow entire faulty current through the fuse element during any faulty condition that means it is desirable to insert a fuse unit at that point of the circuit through which entire current will flow even in the faulty condition. Now let us assume the situation where fuse element is inserted into the neutral path of the circuit. In that case in earth fault condition of the circuit, even the neutral fuse is blown out, the phase of the circuit will still get neutral or earth path through the fault of the system and hence there will be still huge current drawn from the supply by the system even after neutral fuse is blown out. Hence the faulty portion of the system is not at all isolated from the mother system although the neutral fuse is melted and disconnected.
Neutral is nothing but the return path of the current through the load. If the fuse unit inserted on phase is disconnected there will be no further current drawn from the source by the circuit, hence there will be no return current through the neutral path also. Hence after disconnecting the fuse unit of live phase, there will be no further need of disconnecting neutral path from the source. Hence there is no need of inserting fuse unit in the neutral path.
In three phase system, the neutral only carries the summation of the currents in three live phases and maintains the star point of the system at earthed potential. If a fuse element is inserted into the neutral path of a three phase system and accidentally it is disconnected then the star point will no longer be at earth potential instead it would be floating which is not desirable for three phases with neutral earthed system.
From safety point of view, fuse unit should not be inserted in neutral even in the single phase system because the single phase load is off either phase or neutral fuse is blown out. If only neutral fuse is blown out, there will be still a live voltage on the faulty equipment and hence by mistake if anyone touches the life conducting part of the equipment by thinking that the equipment is totally dead, he will get saviour electrical shock.
These are the reasons for which fuse unit is not provided in neutral.
Is This Answer Correct ? | 0 Yes | 0 No |
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