Fuse for Neutral

A fuse is just a conductor. It's like adding a very short length of wire to the existing conductor.

Why do you ask?

i gave one possible diagram, which had two fuses, but they were both phases, no neutral.

http://cr4.globalspec.com/comment/816183/Re-Wiring-an-Ice-Cube-Relay-to-Latch

i could not see any neutral having a fuse, have i missed something ?

Fuses in neutrals are prohibited under British Standard 7671 on safety grounds.

The neutral is there to carry the imbalance current, which is a function of the difference between the phase loads and an expression of the single phase loads. Imbalance current is simply the vector sum of the phase currents.

Don't even think about it. Here's why. Fuses in series (because that's what you're talking about, them being on the same current path), are NOT guaranteed to blow simultaneously (even if they are the closest match), not even that the smaller value fuse will blow first (many factors control that), or that smaller value fuse will blow at all. Now imagine the neutral side positioned fuse to blow and phase side not. The whole circuitry will go to live side potential. Not much protection from a potentially faulty circuit (since it blew a fuse, right?) S.M.

Some time even switch is in open condition,there will be small current on the load side.what is the reason can explain anyone.(After open the switch(off),Floracent lamp is illuminate little bit)

Fluorescent lamps glow due to electromagnetic fields, doesn't need a current through the system...

http://www.doobybrain.com/2008/02/03/electromagnetic-fields-cause-fluorescent-bulbs-to-glow/

"Fluorescent lamps glow due to electromagnetic fields, doesn't need a current through the system..."

But electromagnetic fields are caused by currents only...!

It would be against most wiring codes. BS7671 for certain.

How do you think provision of a fuse would avoid unbalance currents? Unbalance curren is a phenomenon of unequal distribution and/or unequal utilisation of single-phase loads amongst the three phases of a three phase system.

Moreover, many Standards & Regulations in the world prohibit the provision of fuse or cut-out in the neutral. If you are from India, the Indian Electricity Rules, 1956, vide Rule No. "31. Cut-out on consumer's premises- (1)The supplier shall provide a suitable cut-out in each conductor of every service-line other than an earthed or earthed neutral conductor or the earthed external conductor of a concentric cable within a consumer' s premises, in an accessible position. Such cut-out shall be contained within an adequately enclosed fireproof receptacle.

Where more than one consumer is supplied through a common service-line, each such

consumer shall be provided with an independent cut-out at the point of junction to the

common service.

(2)Every electric supply line other than the earth or earthed neutral conductor of any system

or the earthed external conductor of a concentric cable shall be protected by a suitable cut-out

by its owner".

mohamedhajah; only if you all conductors at the same instant. perry

I am sure you are talking about a single phase system.If you need to break the neutral,you can use a 2 pole circuit breaker.

Couple of days back there was a thread (ice cube relay?.)showing fuse in phase and neutral.

It doesn't make it correct.

if u want to avoid and protect unbalance in neutral go for ELCB if its of lower rating.

Here in this drawing 2A fuse put in the both phase and neutral side for indication light.Actually it is in parallel connection,so other circuit will not be affected.Can any one suggest me this drawing is correct or not.

Fuses in neutrals are not permitted by British Standard 7671, as already stated.

Much ado about a non-situation, i do believe.

Current cannot flow through a neutral unless it also flows through a phase, right? So, if there is a fuse in the phase, it will operate and cut off the fault current....so why another fuse in the neutral? No current can flow through neutral alone can it?

BS and other codes are quite right in prohibiting a fuse in the neutral.

Due to poor Neutral earthing in Generator,Return current is possible to flow.Actually when i was checking with neutral,tester had illuminated

There need to be 'go and return' paths for the current. From what you say, there is no current in phase, but only in the neutral ??? i am perplexed. Can you please explain a little more?

I think for motor control ciruits in a panel,fuse is necessary in neutral also,as we have to physically isolate the neutral from other feeders of panel during working on this particualr feeder, from the safety point of view.The fault in other feeder will reflect on the feeder personnel ae working.(even if the working agency touches the neutral & earth by mistake he/she may get shock.)

Pls correct/clarify if I am wrong.

Then the correct thing to use is a neutral link, not a fuse. Neutral links are permitted under British Standard 7671.

yes you can use fuse if you like but to solve the unbalance current is not the good idea you need to check the phasing wire and your equipment to balance the current !

maybe your line1/neutral have 1unit motor 415acv 60amp then your line2/neutral have 3unit of 415acv 60amp motor then your line3/neutral have 5unit of 415acv 60amp each that make your current unbalance you need to make even connection !! hope this will give you hoe to balance your current !!

An <...unbalance current...> is a phenomenon that does not need a <...fuse...> for protection. It is the job of the <...neutral...> conductor to carry it.