Sheet E-104: Zone 7 Medium-Voltage One-Line — Utility PCC, One Radial Trunk, Six Transformers

What this sheet shows

E-104 is the Zone 7 medium-voltage single-line, marked not to scale, for a 12.47 kV, 3-phase, 60 Hz service taken as the utility input per the service agreement. The column headings are the handoff: utility side, owner radial trunk, buried MV drop, OEM package. MVS7-SRC is the zone source at PCC-7, with the upstream recloser drawn on the utility side of a vertical line labeled PCC boundary. The owner trunk, tagged Z7-OH, then feeds six identical paths: loadbreak cutout FCO7-01 through FCO7-06, buried drop MV7-UG-01 through MV7-UG-06, OEM switch and fuses XFP7-01 through XFP7-06 (detail 1 / E-106), internal run MV7-INT-01 through MV7-INT-06, and transformer T7-01 through T7-06. Each transformer is marked 12.47 kV delta / 480Y-277 V at 2500 / 2600 kVA. AUX7-IF leaves the bottom of the same trunk, labeled auxiliary protected feeders rather than another of those six paths.

Design intent you can read off the sheet

The PCC is a drawn boundary with the duties written on it. Protection, metering and lockable service isolation are marked BY UTILITY. Existing utility apparatus may satisfy those functions, and no additional recloser is specified, so the upstream-recloser symbol stays on the utility side of the line. Past that line the owner has one radial overhead trunk, Z7-OH, and the sheet states there is no medium-voltage zone tie. Each of the six paths has its own cutout, and every tap leaves that same trunk: the cutout is the per-path device, and Z7-OH is the common one. PCC position and route length are not fixed here; they follow utility-approved access and a site survey. The two feeders come from the same substation — Zone 7 per the service agreement, Zone 8 at 8 MW — and the upstream recloser remains by the utility. Mechanical and auxiliary transformer feeders are additional. The sheet says thirteen paths are critical power only, and the closing note says the 13 critical paths do not include auxiliary transformers. This drawing shows six Zone 7 transformers and states the thirteen-path count without drawing all thirteen devices on this sheet. Zone 8 is named only as the other feeder. The same boundary question is taken up in the electrical architecture notes.

Conductor and protection schedule

The schedule prints two currents and means them differently. The trunk design-current basis is 341.2 A at 12.47 kV and 0.95 power factor, and that line calls the figure the input limit per the service agreement. The transformer primary is a separate line: 115.7 A at 2500 kVA and 120.4 A at 2600 kVA. Nothing on the sheet adds the path primaries and calls that total the trunk rating. The overhead conductor is 336.4 kcmil ACSR Linnet; the same line names site thermal, sag and fault checks and does not give their outcome. Each drop is 3 × 1/C 15 kV shielded aluminum, with 1/0 AWG stated as the initial size and a burial and fault check named beside it. At the tap, each cutout is 3 × 1P, a 15 kV / 200 A holder. The sheet then says the holder rating is not the fuse-link rating, and that link selection follows full TCC coordination, so 200 A cannot be copied off this drawing as the fuse. Riser, termination, bonding and the OEM integral arrangement are sent to detail 1 / E-106.

Status

Published at Design Development — Public Edition P1 status (title block: 2026-09): a reference design for study and evaluation, not a construction issue, carrying its open items as sheet notes. An OEM general arrangement and data sheet dated 08 SEP 2026 leaves a 2500/2600 kVA discrepancy; the capacity study uses 2500, and both numbers stay on every transformer block so the pair remains visible. The drop conductor is an initial size. No fuse-link ampere rating is printed. PCC position and route length follow utility-approved access and a site survey. The interfaces the sheet lists, and does not close, are utility PCC, grounding and isolation; site route, soil and fault level; and protection curves. AUX7-IF is drawn as a stub for auxiliary protected feeders. Its load / count / protection line names a schedule, and the last note says the auxiliary feeder schedule remains open.

Sheet guide — the devices on this drawing

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