Parking lot lighting design

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Below is the lighting design problem I am working on. I have worked through most of it but I could use some additional assistance.

Design a series lighting scheme with 15 luminaries staggered by 100 feet down a right of way, power a trailer and provide lighting for a parking lot. The trailer operates at 1 phase 120/240 V and has a 100 amp breaker panel and it is found that four luminaries are needed to provide the necessary illumination for the parking lot. There is 480 V 1P 3W coming from the substation. Currently my design has the 480 V going to a main panel and from there, feeding two sub panels. The first sub-panel has a 25 kVA step down transformer 120/240 1P 3W to power the trailer and the four 265 VA luminaries at the parking lot. The second subpanel powers the series of 15 luminaries (150 W rating each) at 480 V.

I have designed the main panel as a 225 amp panel, but I am not sure how to size the main breaker for the panel? I did calculate the individual circuit breaker from the primary of the transformer to be 80 amp and a 20 amp breaker for the series lighting load.​
 

Smart $

Esteemed Member
Location
Ohio
I don't see why you need a main panel and two subpanels when one main panel is enough...???

Also best to put the stepdown transformer at the trailer end of the run.
 
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