Sheet E-105: Zone 8 Medium-Voltage One-Line — One Radial Trunk to Seven Transformers

What this sheet shows

E-105 is the Zone 8 medium-voltage single-line, marked not to scale, for a 12.47 kV, 3-phase, 60 Hz service. The title line states an 8 MW utility input limit. Column headings mark the handoff: utility side, owner radial trunk, buried MV drop, OEM package. MVS8-SRC is the zone source at PCC-8, and the upstream recloser is drawn on the utility side of the vertical line labeled PCC boundary. The owner trunk, tagged Z8-OH, feeds seven paths: loadbreak cutout FCO8-01 through FCO8-07, buried drop MV8-UG-01 through MV8-UG-07, OEM switch and fuses XFP8-01 through XFP8-07 (detail 1 / E-106), internal run MV8-INT-01 through MV8-INT-07, and transformer T8-01 through T8-07. Each transformer block reads 12.47 kV delta / 480Y-277 V and 2500 / 2600 kVA. AUX8-IF leaves the trunk below those seven paths, labeled auxiliary protected feeders rather than another of those paths.

Design intent you can read off the sheet

The PCC is a drawn boundary, and the notes put the duties on the utility side of it. Protection, metering and lockable service isolation are marked BY UTILITY. Existing utility apparatus may satisfy those functions; no additional recloser is specified. Past the boundary the owner has one radial overhead trunk, Z8-OH. The sheet states there is no medium-voltage zone tie. Each of the seven paths has its own cutout, and every transformer tap leaves that same trunk: the cutout is the per-path device, and Z8-OH is the common one. PCC position and route length are not fixed on this sheet; they follow utility-approved access and a site survey. Two feeders come from the same substation: Zone 7 input per the service agreement, and Zone 8 at 8 MW. The upstream recloser remains by the utility. Mechanical and auxiliary transformer feeders are additional. The notes say thirteen paths are critical power only, and the closing line says the 13 critical paths do not include auxiliary transformers. This drawing shows seven Zone 8 transformers, T8-01 through T8-07, and does not draw all thirteen of those paths. Zone 7 is named only as the other feeder. A single radial trunk and no medium-voltage tie are the boundary drawn here; that boundary is taken up in the electrical architecture notes.

Conductor and protection schedule

The conductor schedule prints trunk duty and transformer primary current as separate lines. Trunk duty is 8 MW / (sqrt(3) × 12.47 kV × 0.95 PF) = 389.9 A. The title names an 8 MW utility input limit, and this line uses 8 MW in that quotient. The transformer primary line of the schedule carries 115.7 A at 2500 kVA and 120.4 A at 2600 kVA. Nothing on the sheet adds the path primaries and calls that sum the trunk duty. 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. Each cutout is 3 × 1P, a 15 kV / 200 A holder. The holder rating is not the fuse-link rating. Link selection follows full TCC coordination, and the sheet prints no fuse-link ampere. Riser, termination, bonding and the OEM integral arrangement are referred to detail 1 / E-106.

Status

Published at Design Development — Public Edition P1 (title block: 2026-09): a reference design for study and evaluation, carrying its open items as sheet notes. An OEM general arrangement and data sheet dated 08 SEP 2026 records a 2500/2600 kVA discrepancy; the capacity study uses 2500, and both numbers remain on every transformer block. The drop conductor is stated as an initial size. No fuse-link ampere is printed. PCC position and route length follow utility-approved access and a site survey. The design-sources block names utility PCC, grounding and isolation; site route, soil and fault level; and protection curves. The one item the sheet itself marks open is the auxiliary feeder schedule. AUX8-IF is a stub labeled auxiliary protected feeders. Its load / count / protection line names an AUX schedule, beside a blank rectangle, and the closing note says the auxiliary feeder schedule remains open.

Sheet guide — the devices on this drawing

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