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new service phase rotation

Merry Christmas
M

malachi constant

Senior Member
Location
Minneapolis
Project in the midwest, new construction of a municipal building. Reports from the site are that the electrical contractor wired the building counterclockwise and folks are expressing concern. The building system includes paralleled generators and a docking station for portable genset / load bank testing.

I am the engineer on the project, and know that the physics works just fine so long as everything up and down the line is wired the same way. What I don't know is how common or uncommon CW vs CCW is, and what concerns if any I should have. I've been around 25 years and have never even heard this question asked, so just am not sure what is typical or how big of a deal it is. Anything you all can teach me here is appreciated.
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
What do you mean by the contractor wired everything CCW? Did they swap two of the phases from the POCO?
 
M

malachi constant

Senior Member
Location
Minneapolis
infinity said:
What do you mean by the contractor wired everything CCW? Did they swap two of the phases from the POCO?
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The email to me reads: "it was brought up this morning about the building being wired counterclockwise, which is apparently not the industry standard". That's all I know. I imagine the utility is wired standard. I have a meeting with them in a bit and will try to understand the situation.
 
J

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
malachi constant said:
The email to me reads: "it was brought up this morning about the building being wired counterclockwise, which is apparently not the industry standard". That's all I know. I imagine the utility is wired standard. I have a meeting with them in a bit and will try to understand the situation.
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In my 50 years, I have never considered there being an industry standard rotation.

I have been in facilities where there has not been a consistent rotation standard from one room to the next.
 
H

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
malachi constant said:
The email to me reads: "it was brought up this morning about the building being wired counterclockwise, which is apparently not the industry standard". That's all I know. I imagine the utility is wired standard. I have a meeting with them in a bit and will try to understand the situation.
Click to expand...
Utility can be either way, most I have found have been CCW. It can be up to the electrical contractor to do a power down, and swap it to a desired rotation, but is extremely rare to change what the poco has delivered.
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
IMO there is no standard. As long as the EC kept the phasing the same as the incoming service there is no issue. I doubt that the POCO would even entertain changing anything on their end.
 
Z

zbang

Senior Member
Location
Roughly 5346 miles from Earls Court
Same here, never checked or cared about the utility rotation, only that the motors spin the right way and however you guess, you'll be wrong 70% of the time :ROFLMAO: . (It does become fun when 3-phase power tools are shuffled around to different shop locations and not all of the receptacles are wired the same direction.)
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I see 3ph as delivered by the utility as arbitrary. You have to wire each and every piece to rotate correctly.

I never assume that all of the equipment will rotate the same direction just because I wire them the same.
 
H

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
As long as the system rotation is turning the motor the correct way I wouldn't worry about it. Make the generator turn the motor the correct way also.
It's not like you are soft transitioning.
 
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