Objectionable current on gas main

garbo said:
As long as Ultility companies only supply one high voltage lead to thier thousands of distribution transformers this will be a potential problem.
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don_resqcapt19 said:
That would be a singe wire earth return and is never used in populated areas. The utility uses a common conductor as the neutral for both their high voltage distribution and the secondary of the transformers that supply power to their customers.
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I would not say that is necessarily a SWER. It seems perfectly reasonable to refer to a transformer fed L-N from an MGN to have "only one high voltage lead"
 
don_resqcapt19 said:
That would be a singe wire earth return and is never used in populated areas. The utility uses a common conductor as the neutral for both their high voltage distribution and the secondary of the transformers that supply power to their customers.
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Well here in Philadelphia, the 6th most populated city, PECO had been cutting corners by only supplying one high voltage conductor to every transformer that I ever observed in last 60 years. They never connect the common center tap ( one from primary of transformer and the other to the center tap of the 120/240 volt secondary ) to any other upstream source like a poster stated months ago.
 
garbo said:
. They never connect the common center tap ( one from primary of transformer and the other to the center tap of the 120/240 volt secondary ) to any other upstream source like a poster stated months ago.
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Typically on a single bushing transformer, the other side of the MV winding is connected internally to the tank. I don't think I've ever seen one where it's connected internally to the secondary center tap. There will be a lug on the tank somewhere that the MGN lands on.
 
Well thought I'd post an update my boss went over there with the building super and killed all the breakers to all units and the current dropped to zero on the gas pipe.
 
pipe_bender said:
Well thought I'd post an update my boss went over there with the building super and killed all the breakers to all units and the current dropped to zero on the gas pipe.
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Which just shows that there's one or more parallel paths created by at least two neutral-gas bonds in the building. (And that this talk about whether utilities ground a primary conductor is off topic.)
 
jaggedben said:
Old appliances with bare neutral conductors that bond frames are only allowed to be connected to service panels, i.e. the meter pack in this case, not subpanels in the units.
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So it seems the 2023 NEC may have overlooked this case as 2023 NEC 250.140 (B) appears to allow a 3-wire connection to remain when a service is converted to a sub panel. I am not too familiar with CSST gas pipe and how its bonded, but it does seem like there is a parallel neutral path for the entire feeder if 250.140(B) in the 2023 NEC is used with a gas / electric range or a range with a connection to a metal water pipe such as a "pot filler".
 
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garbo said:
Well here in Philadelphia, the 6th most populated city, PECO had been cutting corners by only supplying one high voltage conductor to every transformer that I ever observed in last 60 years. They never connect the common center tap ( one from primary of transformer and the other to the center tap of the 120/240 volt secondary ) to any other upstream source like a poster stated months ago.
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In many cases the connection between the primary neutral and the secondary neutral is inside the transformer.
 
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