voltage drop?

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T mcc

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Location
tennessee
Occupation
Electrical Superintendent
I have some long feeders to buildings that are single phase 240V. It shows on one line that the parallel feeds are maintained from meter to MCB at meter stack then long run on all in excess of 700' to Disconnect on building and from that to MLO on panel. My question is this if they are being run for voltage drop and nothing else, why can they not be one set from meter to MCB and from disconnect to panel MLO. The long distance is where the parallel wires should be taking care of the voltage drop.
 

Dennis Alwon

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Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I have some long feeders to buildings that are single phase 240V. It shows on one line that the parallel feeds are maintained from meter to MCB at meter stack then long run on all in excess of 700' to Disconnect on building and from that to MLO on panel. My question is this if they are being run for voltage drop and nothing else, why can they not be one set from meter to MCB and from disconnect to panel MLO. The long distance is where the parallel wires should be taking care of the voltage drop.
It is possible that it can be but if it is drawn that way you are obligated to comply. It would appear the long runs are the only area where parallel conductors would be needed if in fact it is just for VD.

I suspect you would need to do a vd calculation and show that it can be done
 

GoldDigger

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Location
Placerville, CA, USA
Occupation
Retired PV System Designer
If the parallel feeds include the service drop as well as meter to MCB, it may be that POCO is requring that to avoid unnecessary VD (and power waste) on their side of the meter, and are simply continuing on to the service point.
If POCO feels it is necessary, I would definitely question the single set on the long feeder.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
If the parallel feeds include the service drop as well as meter to MCB, it may be that POCO is requring that to avoid unnecessary VD (and power waste) on their side of the meter, and are simply continuing on to the service point.
If POCO feels it is necessary, I would definitely question the single set on the long feeder.
But of course short runs of conductors with appropriate ampacity do not contribute significantly to Vd.
 
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