Surge protection on fuses

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hockeyoligist2

Senior Member
Friday night I got a call during a bad storm to one of our sewer plants. Lightning had Knocked out a PLC and some other things on the same line. It has surge protection and it was fused. I have never saw a fused surge protector. (new installation by a contractor) All 3 fuses (480 system) were blown and I don't know if they were blown from this surge or an earlier one. Is that a normal practice? Or did the contractor make a mistake? Seems to me if you fuse it, it may work one time then the next it is useless? It is still under warranty, so before I point fingers, I would like to know the opinions?
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
hockeyoligist2 said:
Friday night I got a call during a bad storm to one of our sewer plants. Lightning had Knocked out a PLC and some other things on the same line. It has surge protection and it was fused. I have never saw a fused surge protector. (new installation by a contractor) All 3 fuses (480 system) were blown and I don't know if they were blown from this surge or an earlier one. Is that a normal practice? Or did the contractor make a mistake? Seems to me if you fuse it, it may work one time then the next it is useless? It is still under warranty, so before I point fingers, I would like to know the opinions?

I have never seen one done this way. but I don't see how you could install anything that did not have some kind of OCPD protecting the wiring.

I would be inclined to look at the drawings for the project and see what the engineer designed. Or look at the instructions for the SS.
 

dereckbc

Moderator
Staff member
Location
Plano, TX
Dumb question, which side of the disconnect is it installed on. If ahead of the disconnect it is a Surge Arrestor, if downstream or after the disconnect it is TVSS. Two differnt sets of rules apply. It it is a Surge arrestor, then no OCPD is required but allowed. If it is a TVSS, then OCPD is required. Refer to 280 and 285
 

hockeyoligist2

Senior Member
dereckbc said:
Dumb question, which side of the disconnect is it installed on. If ahead of the disconnect it is a Surge Arrestor, if downstream or after the disconnect it is TVSS. Two differnt sets of rules apply. It it is a Surge arrestor, then no OCPD is required but allowed. If it is a TVSS, then OCPD is required. Refer to 280 and 285

It is ahead of the disconnect. Talked to the maufacturer, they said it's ok to be fused but if someone had pulled the fuses they should be responsible. No way to prove who done this. Sorry that you thought it was a "Dumb Question"! I was always told the only dumb question was one that wasn't asked! Did you have a bad day or something? I'm here to learn!


:)
 

ron

Senior Member
Knowing Dereck a bit, I will suggest that he was commenting on his own question, not yours being dumb.

Many large TVSS' are fused for self protection. They must have an acceptable withstand rating and survive long term overvoltages without catching fire, and they do that with fuses.
 

hockeyoligist2

Senior Member
ron said:
Knowing Dereck a bit, I will suggest that he was commenting on his own question, not yours being dumb.

Many large TVSS' are fused for self protection. They must have an acceptable withstand rating and survive long term overvoltages without catching fire, and they do that with fuses.


Sorry Dereck, I've been misunderstood here before myself!
 
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