I've worked on manholes/property line boxes where the incoming low voltage (480V) utility service conductors to the manhole were much smaller than those we spliced to run to the main service switchboard. For example, the utility company ran 3 sets of 3-500MCM to the manhole and we spliced them and ran 8 sets of 3-500 MCM to our 3000A board. Why is it the utility can run so many fewer sets than the customer? Hope I'm being clear.
Utility company service entry conductors
- Thread starter aramg83
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The utilities have years of documentation and experience that they rely on for selecting conductors based on actual load and diversity and their conductors are often under different conditions (free air, etc) than the customers, but, I think the bottom line is there is far more concern about the safety of a conductor inside a building than in a man-hole or outside
area. A burning condcutor inside a building poses more threat than one in a street manhole.
area. A burning condcutor inside a building poses more threat than one in a street manhole.
M
MadWulf
Guest
Utilities do not have to comply with the NEC. They set their own rules and codes.
Augie hit it on the head. This is the same reason they can set a utility transformer that is much smaller than the service size. They know it will never be loaded 100%.
Augie hit it on the head. This is the same reason they can set a utility transformer that is much smaller than the service size. They know it will never be loaded 100%.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
They size their wires on average projected load, not possible maximum load. This works good most of the time, but I have seen them miss a couple of times on wire size and transformer size.:lol:
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