Step down transformer

[augie47]

IMO, using a 4/0 is a waste as a smaller conductor would still give you a reasonable voltage drop plus the transformer will likely have taps to compensate far any drop.

Minor note: You mention Sch 40 PVC. More than likely you would need Sch 80 to meet 300.5(D)

 

[Rock86]

IMO, using a 4/0 is a waste as a smaller conductor would still give you a reasonable voltage drop plus the transformer will likely have taps to compensate far any drop.

Minor note: You mention Sch 40 PVC. More than likely you would need Sch 80 to meet 300.5(D)

Agreed. I ran the numbers through southwire voltage drop calculator and got a much smaller conductor size.

Double check your values.

 

[Roscoe]

Yeah, I thought about using number one or number two but my load calculators kept throwing me tat 2/0 and 4/0 which seemed kind of large, especially being that it’s 480 V on the primary side on the secondary. It’s 208 3 phase on my 45 KV transformer, I was just trying to keep the voltage drop down to minimum of 1%. I’ve never done a large scoreboard like this before. I was just trying to be extra cautious. I wasn’t sure how sensitive the equipment is. To voltage drop.

 

[Roscoe]

IMO, using a 4/0 is a waste as a smaller conductor would still give you a reasonable voltage drop plus the transformer will likely have taps to compensate far any drop.

Minor note: You mention Sch 40 PVC. More than likely you would need Sch 80 to meet 300.5(D)

The only schedule 40 will be underground in between my concrete pad, where my two service disconnects will be one for the transformer and one for the scoreboard. I will have schedule 80 coming out of the load side disconnect attaching to schedule 40 PVC underground till it reaches the post for the scoreboard Then I will switch over to rigid conduit until I reach the catwalk and then I will switch over to metallic seal tight for their load center

 

[electrofelon]

Yeah, I thought about using number one or number two but my load calculators kept throwing me tat 2/0 and 4/0 which seemed kind of large, especially being that it’s 480 V on the primary side on the secondary. It’s 208 3 phase on my 45 KV transformer, I was just trying to keep the voltage drop down to minimum of 1%. I’ve never done a large scoreboard like this before. I was just trying to be extra cautious. I wasn’t sure how sensitive the equipment is. To voltage drop.

Most things draw vastly less than nameplate or what the manufacturer says. I can't imagine the thing drawing anywhere near 120 amps at 208 3 phase.