Wow!

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rshane

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I Recently moved to Long Island NY from Charlotte NC. I knew things would be different but holy smokes... I set my first transformer last week... boss told me to do something funny with it...I thought he was "busting my chops" as they says up here in NY;).. He told me to bond the H1 phase to the side of the can... CAN ANYONE EXPLAIN WHY THIS DIDNT BLOW UP?....
 
rshane said:
I Recently moved to Long Island NY from Charlotte NC. I knew things would be different but holy smokes... I set my first transformer last week... boss told me to do something funny with it...I thought he was "busting my chops" as they says up here in NY;).. He told me to bond the H1 phase to the side of the can... CAN ANYONE EXPLAIN WHY THIS DIDNT BLOW UP?....
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Would this happen to have been a delta transformer? Sounds like he wanted it corner grounded.
 
Assuming H1 is on the supply side of the transformer, there are almost no code complinat installations where H1 would be bonded to the transformer case at the transformer.
 
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Yes H1 is the line side of voltage.. I swear I took a thru lug and bonded the thing to the cabinet... I think I can post a picture of it here... I will snap a picture of this tomorrow and post it.. you're gonna flip out... The sales guy that we bought the transformer from tried to explain it to me but he got way over my head talking magnetic fields.. I didnt wanna sound dumb so I nodded alot and smiled.. I was hoping someone here could explain it a lil more clear... Your help would greatly be appreciated and it would help me not feel so dumb the next time around lol... tune in tomorrow and I will show you exactly what I did:)
 
rshane said:
I Recently moved to Long Island NY from Charlotte NC. I knew things would be different but holy smokes... I set my first transformer last week... boss told me to do something funny with it...I thought he was "busting my chops" as they says up here in NY;).. He told me to bond the H1 phase to the side of the can... CAN ANYONE EXPLAIN WHY THIS DIDNT BLOW UP?....[/QUOTE

It did not blow because a delta winding has no ground reference (before you ground a leg) so there is no current path (or short.)
Assuming a Delta winding on the primary side, electrically, this would not cause a problem. As earlier mentioned, corner Delta's are grounded on the secondary side for a reason. I do not recall any code that covers this. The question is, why would you want to do this?:?
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The OP does not say if this in on the MV side or the LV side, in post 5 he does say that he bonded one of the phase conductors on the primary side of the transformer, if this is on the NEC side of the service point then is is a code violation, as the transformer is part of a feeder circuit and you can't re-ground a grounded conductor, and the grounded conductor is required to be the "B" phase, if you grounded a un-grounded conductor and there is no path for fault current then you have now caused this case to be at line to line voltage to earth, if there is a fault path then it will (we hope) open the OCPD.

two things:
1. Is the feeder feeding this transformer from a grounded system?
2. Is the phase you bonded with the H1 the grounded phase of that system?

Other things would make it more clear as to what you have is, is this a 3-phase transformer?
 
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hurk27 said:
The OP does not say if this in on the MV side or the LV side, in post 5 he does say that he bonded one of the phase conductors on the primary side of the transformer, if this is on the NEC side of the service point then is is a code violation, as the transformer is part of a feeder circuit and you can't re-ground a grounded conductor, and the grounded conductor is required to be the "B" phase, if you grounded a un-grounded conductor and there is no path for fault current then you have now caused this case to be at line to line voltage to earth, if there is a fault path then it will (we hope) open the OCPD.

two things:
1. Is the feeder feeding this transformer from a grounded system?
2. Is the phase you bonded with the H1 the grounded phase of that system?

Other things would make it more clear as to what you have is, is this a 3-phase transformer?
Click to expand...

To me, H1 means the high side of a step down transformer.
Also, if the supply transformer to his transformer is a delta winding then your code violation would not apply.
 
hurk27 said:
T
two things:
1. Is the feeder feeding this transformer from a grounded system?
2. Is the phase you bonded with the H1 the grounded phase of that system?
Click to expand...

Seems like the only real logical possibilities if this thing didn't trip an OCPD when energized.
 
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