Step down transformer

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)
 
augie47 said:
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)
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Agreed. I ran the numbers through southwire voltage drop calculator and got a much smaller conductor size.

Double check your values.
 
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.
 
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augie47 said:
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)
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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
 
Roscoe said:
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.
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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.
 
electrofelon said:
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.
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Another question for you or anyone out there that could help me the transformer and strut frame will be directly behind the scoreboard on a pad. I don’t really feel that there’s anything other than putting a structure around it that would protect the switch gear and transformer. The transformer will be dead center behind a giant 4 foot diameter support column for the new scoreboard and I will have a disconnect on each side of the transformer one for the line side one for the load side, I can’t think of any ideas of how I should protect the equipment if I even need to, but they are fused disconnect so I’d hate for a soccer ball to hit that thing at full steam and knock it loose, but maybe I’m just overthinking. It is quite a distance from the Gold Coast to the scoreboard. I’d say at least 100 foot.
 
Roscoe said:
Another question for you or anyone out there that could help me the transformer and strut frame will be directly behind the scoreboard on a pad. I don’t really feel that there’s anything other than putting a structure around it that would protect the switch gear and transformer. The transformer will be dead center behind a giant 4 foot diameter support column for the new scoreboard and I will have a disconnect on each side of the transformer one for the line side one for the load side, I can’t think of any ideas of how I should protect the equipment if I even need to, but they are fused disconnect so I’d hate for a soccer ball to hit that thing at full steam and knock it loose, but maybe I’m just overthinking. It is quite a distance from the Gold Coast to the scoreboard. I’d say at least 100 foot.
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I guess I would have to see the site and setup to have an opinion on if more protection is needed. also not sure if aesthetics are an issue.
 
There’s also a fence behind it as you can see and it’s hard to see, but there’s also a 4 foot tall chain-link fence in between the existing scoreboard and the track I talk to my local official. He says I should be good. I’m just using name a 3R equipment The transformer as well as a name of 3R there’s no sprinklers out there. The only sprinklers are on the field itself, so it won’t be getting any water directly sprayed on it at the most. The only thing I could see my Inspector making me do is put a small lip over the top of the enclosures to deflect direct rainfall. I don’t see why that would be necessary, but they’ve made me do it in the past.
 
Roscoe said:
The only thing I could see my Inspector making me do is put a small lip over the top of the enclosures to deflect direct rainfall. I don’t see why that would be necessary, but they’ve made me do it in the past.
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A Type 3R enclosure is Listed for protecting against rain falling and puddles on it, so you don't need to add anything.
Some people use Type 12 equipment outdoors because it is gasketed. A Type 12 used outdoors needs a drip hood to guard against puddles.
A Type 3R/12 comes with an integral drip hood.
 
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