Power distribution question

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anbm

Senior Member
Please see attached pictures, there are (2) utility pad mtg xfmrs in the yard, there is a box (grey color box between two green color xfmrs) between them,
both xfmr serve the building main switchboard, there is no record drawing, what is the box between two xfmr? Will both xfmrs feed that box, then the circuit come out of the box and power building main swbd? 02.JPG

01.JPG main underground circuit run from the box to the building main switchboard?
 

anbm

Senior Member
Looks like a primary MV voltage switch.
It is not, in some areas, the power company person said that two xfmrs secondary feed to the box (I am thinking the box as a panel), then the box will feed the building's main switchboard, does anyone have similar experience?
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Retired Electrical Engineer - Power Systems
It is not, in some areas, the power company person said that two xfmrs secondary feed to the box (I am thinking the box as a panel), then the box will feed the building's main switchboard, does anyone have similar experience?
Not so much a panel as a tap box, like a power distribution block. It is also possible it is a 'selector switch'.
 

theophilus88

Professional Architectural Engineer
Location
St. Louis, MO
Occupation
Professional Architectural Engineer
Without having much information, I would assume the following three... CT Cab, Main Switch, or Tap Box. Can someone open it up for you?
 

anbm

Senior Member
Can two xfmrs power a comon tap box? should the xfmrs be in phase to make it work? Will call power company if they can open that cabinet.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Retired Electrical Engineer - Power Systems
Can two xfmrs power a comon tap box? should the xfmrs be in phase to make it work? Will call power company if they can open that cabinet.
Yes it is possible, but unlikely. Yes the transformers would need to be in phase to allow them to be paralleled.
 

anbm

Senior Member
I would say it is most likely a CT cabinet. Look for a small conduit out of it going to a meter.
There is no meter, these two xfmr feeds a main swbd located inside the building, the swbd then feeds several meter tap cans - have sub-meters for residential units (this is a 7 floor high rise multifamily bldg).
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Paralleling transformers is not unusual. Ideally they are identical models and it must be assured that any tap changers are set identically.

POCO does not care about individual OCPD.
 
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