Fuse failures

[kwired]

The rupturing capacity of a fuse has nothing to do with lightning.In fact a fuse has nothing to do with interrupting a lightning current.My guess is the subject fuse in your case was not properly secured in its holder with the result the electromagnetic force of the lightning current displaced it .

If current flowing through the fuse is higher than fuse rating why wouldn't it blow? In the event of lightning the voltage is likely still high enough to jump the gap even after the fuse blows, then the EMF can cause further damage.

 

[SG-1]

You have got approved paper fuses?Because the problem is on heating, the paper emits conductive vapor which on being absorbed by sand makes it in turn conductive.The result is when the fuse tries to interrupt a fault current,the fault current may continue flowing through the sand even after the fuse element is broken!

The fuse is made by Bussman. That is very interesting as to why the fuse can catch fire.

 

[SG-1]

The rupturing capacity of a fuse has nothing to do with lightning.In fact a fuse has nothing to do with interrupting a lightning current.My guess is the subject fuse in your case was not properly secured in its holder with the result the electromagnetic force of the lightning current displaced it .

The fuses were properly installed in the holder & very difficult to manually remove. The ejected fuses were always in more than one piece. One end was always gone. This was less objectional than than the fence controller, charger, being blown apart. This did not happen every time, many times the fuse was successful.

 

[templdl]

The fuses were properly installed in the holder & very difficult to manually remove. The ejected fuses were always in more than one piece. One end was always gone. This was less objectional than than the fence controller, charger, being blown apart. This did not happen every time, many times the fuse was successful.

Mmm, "This did not happen every time, many times the fuse was successful." Am I missing something here? Why so many times? Usually if a fuse blows once the issue is addressed to resolve the reason the fuse blew in the first place. But it appears as though this s a regular occurance which I would take issue with. Was this addressed in the OP?

 

[kwired]

We are talking about an electric fence charger and lightning. If you have miles of fence - not uncommon at all for livestock pastures - you are going to have lightning incidents at times. You can't ground the fence - that defeats the purpose of electrifying the fence in the first place.

 

[templdl]

We are talking about an electric fence charger and lightning. If you have miles of fence - not uncommon at all for livestock pastures - you are going to have lightning incidents at times. You can't ground the fence - that defeats the purpose of electrifying the fence in the first place.

Is this a rabbit trail from the OP? Now if this is now about an electric fence did I miss the point that the fence also had a lightnng arrestor in some form or another?

 

[T.M.Haja Sahib]

The ejected fuses were always in more than one piece. One end was always gone.

There is no way to explain this other than the electromagnetic force of the lightning doing it.

..... many times the fuse was successful.

It might not be the lightning current that blew the fuse, but it might be the power frequency follow through current from the power system that might have blown the fuse.

 

[T.M.Haja Sahib]

If current flowing through the fuse is higher than fuse rating why wouldn't it blow?

The extremely short duration of lightning current does not cause the fuse to operate.

 

[T.M.Haja Sahib]

Is this a rabbit trail from the OP?

No.I did not bring up the topic of electric fence.:happyno:

 

[iwire]

I just want to say thanks to TM for starting his own thread to discuss what he wants too without side tracking another persons thread. :thumbsup:

 

[T.M.Haja Sahib]

I just want to say thanks to TM for starting his own thread to discuss what he wants too without side tracking another persons thread. :thumbsup:

I never have any intention to side track another person thread.But if so pointed out by the person concerned,I immediately would stop it because my(our) real intention is to help.....

 

[SG-1]

Mmm, "This did not happen every time, many times the fuse was successful." Am I missing something here? Why so many times? Usually if a fuse blows once the issue is addressed to resolve the reason the fuse blew in the first place. But it appears as though this s a regular occurance which I would take issue with. Was this addressed in the OP?

This was a slow painful process. After each storm some new mitigation solution was added. Many had no effect. The KTK-R always worked after the fuses were added on the 5KV side of the fence controller. That fuse would be blown too. Standard fence arrestors caused more problems, mode of failure was a dead short. The 7KV intermediate class arrestors have been in service now for several years. These storms were very severe. One wacked out the display on an indoor/outdoor thermometer. These storms would ring the bell in our heat detectors inside the house.

 

[SG-1]

There is no way to explain this other than the electromagnetic force of the lightning doing it.

I do not doubt that there were large electromagnetic forces at play.


It might not be the lightning current that blew the fuse, but it might be the power frequency follow through current from the power system that might have blown the fuse.

That was considered & a surge arrestor was placed on the 120 volt side to keep the voltage across the fuse within it's rating.

 

[T.M.Haja Sahib]

That was considered & a surge arrestor was placed on the 120 volt side to keep the voltage across the fuse within it's rating.

I have a suggestion.

Do not use the arrangement you described above.

If you do not want this fuse to blow,use one more fuse much smaller (50% or more) than it and in series with a serge arrester.When the arrester operates,only this smaller size fuse may blow, leaving the other intact.

When it does,do not forget to replace it.

In this way you may solve your problem.

 

[T.M.Haja Sahib]

The smaller series fuse should be downstream to the fuse you want not to blow.

 

[templdl]

I just want to say thanks to TM for starting his own thread to discuss what he wants too without side tracking another persons thread. :thumbsup:

Thanks, that was my point. I believe the intent of this form is not to confuse the OP but rabbit trails and diversions. And I do see that they took your suggestion and started a new thread
Although I not necessarily agree to close a thread but when the objective of the OP gets too far off base that the responses are no longer relevant to the topic of the OP, yes, I believe that the subject should be closed. Those that have changed the topic to something else should start a new thread. Again my concern is that the follow-ups get so far out of whack that the person who started the thread becomes inundated by convoluted irrelevant responses with rabbet trails.
All to often the last response of a thread have noting to do with the OP.

 

[kwired]

A fuse clears a fault after its element arcing for some time.But if its arc continues beyond a certain duration perhaps due to inappropriate higher size of its element,its cartridge might also be damaged by the arc, as the fuse failed to clear the fault. Has any one come across such a situation ? Thanks.

OP asks if someone has seen a situation where fuse fails to clear a fault before causing damage to cartridge and/or fuse holder. Someone suggests a situation where this does happen - although the interrupted current is from a lightning incident. Obviously not what the fuse was intended to protect from but not really off topic either.

 

[T.M.Haja Sahib]

Thanks, that was my point. I believe the intent of this form is not to confuse the OP but rabbit trails and diversions. And I do see that they took your suggestion and started a new thread
Although I not necessarily agree to close a thread but when the objective of the OP gets too far off base that the responses are no longer relevant to the topic of the OP, yes, I believe that the subject should be closed. Those that have changed the topic to something else should start a new thread. Again my concern is that the follow-ups get so far out of whack that the person who started the thread becomes inundated by convoluted irrelevant responses with rabbet trails.
All to often the last response of a thread have noting to do with the OP.

I agree to what you say.But it should be the OP who need to say so.Whoever else is saying such a comment is just playing a game,IMHO.

 

[Hv&Lv]

OP asks if someone has seen a situation where fuse fails to clear a fault before causing damage to cartridge and/or fuse holder. Someone suggests a situation where this does happen - although the interrupted current is from a lightning incident. Obviously not what the fuse was intended to protect from but not really off topic either.

Maybe not the same thing, but there are expulsion fuse cartriges that fail occasionally, I have had them blow in half when throwing them back in on a fault (unknown, of course).

 

[T.M.Haja Sahib]

there are expulsion fuse cartriges that fail occasionally, I have had them blow in half when throwing them back in on a fault (unknown, of course).

Did it cause any damage to the downstream equipments?

If no,I think the rupturing capacity of the fuse might have been exceeded so that even though the fuse failed catastrophically,it nevertheless caused no damage to the downstream equipments it protected.Correct?