Phase and Neutral Fuse Blown

[arunkumar2k5]

Hi all,
In my System, there is an input AC filter which we have designed for the EMI purpose. WE have a 1.6A fuse on both the Phase and Neutral followed by an Capacitor ( 0.1 uf 750 V) and an Inductor. When the tester connected the AC Power ( 230 v 50Hz) to the System , There is no output from the Filter , we inspected and found that the Fuse is blown , both in Phase and in Neutral .


I know Fuse blow is common , one thing Which I couldn't explain myself is when the First Fuse Blows , there is no return path for the second Fuse . I am wondering how this could happen.

Any thoughts ????

 

[alec_t]

when the First Fuse Blows , there is no return path for the second Fuse

It is possible that arcing through metal vapour within the first fuse when it blew allowed enough current to remain flowing to blow the second fuse.

 

[Mike odom]

and/or that they both heated up and blew at the same time, which isn't uncommon, especially if they came out of the same manufacturing batch.

 

[circuitspecialists]

Is there a connection to the third wire ground in your system? Maybe a possibility of a Ground short?

 

[jpanhalt]

Is the neutral grounded in your country? In the US, where neutral is grounded, it is considered bad practice to ever fuse the neutral, because that leaves the possibility that the equipment will be shock hazard to anything else that is grounded.

John

 

[mvs sarma]

in India the neutral is grounded. any user is not Expected to use a fuse on neutral. fuse is expected only on phase wire. If isolation is needed, one should have a dual pole switx\ch for single phase and 4 way switch for 3 phase. a Fuse on neutral , if blows , becomes hazardous floating the live wire across the home.

 

[Nigel Goodwin]

Likewise, I've never heard of fusing the neutral?, it's sounds a crazy (and pointless) thing to do.

 

[picbits]

Likewise, I've never heard of fusing the neutral?, it's sounds a crazy (and pointless) thing to do.

Maybe in a product which could have the live and neutral connected either way round but I agree - not something you normally see.