[Linked Image]

Thanks to bjarney for the photo and following notes:

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This "H-frame" transformer bank about 15 miles away is still standing although the buildings have been leveled. It seems to be a 240/120V 4-wire ∆ bank that served a multi-tenant light-industrial/retail building space, probably built in the late 50s/early 60s.

The disconnected 12kV open-link fused cutouts are visible in the upper-lefthand corner. It's easy to pick out the delta-primary arrangement. The lower six spans are fed by the bank secondary in a {winding/jumpering} confinguration that was very popular at the time. Each tenant had a 120/240V 1ø 3-wire 'lighting' meter, fed from the closer lower 3 secondary spans, and a 240V 3ø 3-wire delta 'power' meter from the farther lower three spans. On the 1ø spans, note the middle conductor looks smaller, for it is bare.

Note the conductor spans [12kV and 240V] are all solid copper, whereas if presently intalled, they would be stranded ACSR {aluminum conductor/steel-reinforced} unless in a high-corrosion area like on the seacoast.

Later 240/120V 3ø services are 4-wire ∆ served through 1 meter. Dual lighting and power metering [at differing rates] disappeared ~25 years ago.

I could not see any kVA rating stenciled on the transformer cans, although they would likely have been on the other {opposite} non-bracket side that was obscured by the mid-day sun. I would guess they are ±75kVA each, for a 225kVA bank. It is routine to have a somewhat larger center transformer for serving both 1 and 3ø, but apparenty that is(/was) not the case here. Nowadays, new 240/120V 3ø service is very limited—208Y/120 and 480Y/277V are the norm.