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I am pretty sure you know what you are doing, but I have some questions, so here goes.
You are saying that even though you and I have breakers between our generators and the utility that we are not protecting the utility?
I must have missed that requirement and the inspector missed it to when I installed the generator about fuses.
Things are getting complicated to be a standby generator owner and scary too boot.
Just recently I took a look at the contactor in my TS, not a great deal of pitting.
Now about the TS, if the contacts welded in my TS, utility could not be fed as the utility contacts are open, or so I thought.
I mean after all the contactor is a common, Normally open, Normally closed unit.
Welded contacts would prohibit the utility from being back fed as I see it because.....
The generator is on the Normally open side of the contactor.
Once utility energizes the control circuit would tell the generator that utility was up.
The generator would stop running and the welded contact would keep utility isolated on the Normally closed set of contacts.
It would not back feed to utility unless someone wired the TS wrong.
TS wiring: Common feeds the circuits, NC feeds Common from utility, NO feeds common from the generator.
Now tell me how the TS contactor fed the utility with power from the generator when the NC contacts were never in contact with the generator feed.
Add to that, how could a set of fuses stopped the problem?
 

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also the safety thing will be the utility company could see a back feed during an outage
from some one who's not running an interlock or whos auto transfer switch (ats) failed to knife out the grid during an outage.
That's just not possible... Any approved transfer switch is break-before-make, so you can't have the utility and generator power interconnected.

Illegal backfeeding, however, should be detected and dealt with most severely!
 

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I agree with you tabora,
You are dead on right about BREAK before MAKE and add to that the TS has switches on the side of the main contactor that add security to the system.
My ATS is rated at 150 amps and it has been in use for eleven years without any excess of pitting.
I am sure that an excessive load could weld the contacts, but who puts 150+ amps on the TS before switching it?
Most generators on a 150 amp TS only can put 90+ amps into the system at full load. (ie: 20 KW)
Generac would be in a world of hurt if they were manufacturing a product that could back feed generator to utility on failure.
I am going to question IowaGold's assessment that the TS was at fault unless it came unglued and fell apart while in use and then I would have to see it to believe my eyes.
But then this guy could have had a back feed system the we do not know about and IowaGold is not explaining it to us.
 

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Illegal backfeeding, however, should be detected and dealt with most severely!

not only do I approve of this message (as the politicos say) I am a victim of such a situation, except this happened to be an improperly connected battery string., Luckily it was only around 100 vdc. Doesn't sound like much, I know. It knocked any sense I ever had outta me, felt worse than the few 208/240 vac hits I'd experienced.
Please, Safety First!
 

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That was rather interesting. The contacts on the sides of all transfer switches are either for coil clearing, position reporting be it local or remote, or form C for many, many other uses.
 

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not only do I approve of this message (as the politicos say) I am a victim of such a situation, except this happened to be an improperly connected battery string., Luckily it was only around 100 vdc. Doesn't sound like much, I know. It knocked any sense I ever had outta me, felt worse than the few 208/240 vac hits I'd experienced.
Please, Safety First!
That is an impressive (in a bad way) event.

I work with 48 VDC routinely and that is already quite impressive.

DC requires very careful use and equipment decisions.
 
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