Aluminum Feeder Freight for a 200 Amp Service Lateral
Service-lateral freight: large aluminum conductors, short run, high weight per foot.
Formula SSC-2026.1
K method · SSC-2026.1
Minimum size
250 kcmil · 127.0 mm²
Single conductor set
Voltage drop
1.70 V
0.71% · end 238.3 V
Power loss
339 W
I²R at the operating current
Required ampacity
200.0 A
Each conductor 205 A
Material estimate
$1,173.50
3 conductors + RMC
Conductor weight
42.1 lb
19.1 kg · approximate insulated weight
Circle diameters track circular mils. The drawing is a schematic, not a conduit-fill layout.
| Item | Net | Waste | Order | Unit price | Line total |
|---|---|---|---|---|---|
| aluminum 250 kcmil · 127.0 mm² | 50 ft one way | cuts excluded | 3 conductors | USD | $936.00 |
| RMC conduit | 50 ft | — | 50 ft | USD | $237.50 |
| Material | Minimum size | mm² | Drop | End voltage | Loss |
|---|---|---|---|---|---|
| aluminum | 250 kcmil · 127.0 mm² | 127.0 | 0.71% | 238.3 V | 339 W |
| copper | 3/0 AWG · 85.0 mm² | 85.0 | 0.64% | 238.5 V | 308 W |
| Distance | Minimum size | Drop | Percent | End voltage |
|---|---|---|---|---|
| 50 ft | 250 kcmil · 127.0 mm² | 1.70 V | 0.71% | 238.3 V |
Show the deterministic formula
Single phase: Vdrop = 2 × K × I × D / cmil. Three phase: Vdrop = 1.732 × K × I × D / cmil. K is 12.9 for copper and 21.2 for aluminum. D is one-way feet.
Percent drop = Vdrop ÷ source voltage × 100. Green is 3% or less, amber is 3 to 5%, and red is over 5%. Power loss is I²R on the current-carrying conductors.
The smallest conductor that meets both the ampacity (125% when continuous) and the drop limit is selected. Ampacity does not include bundling or temperature correction.
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Project: Aluminum Feeder Freight for a 200 Amp Service Lateral
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This sheet is an estimate for ordering and layout discussion. It is not a sealed design. Confirm the quantities with a licensed local professional and the authority having jurisdiction before you buy or build.
Engineering notes
The lateral is 200 A, 240 V, 50 ft, aluminum, in rigid conduit. Ampacity governs. The weight uses about one-third of the copper weight per foot for the same size, which is still a heavy coil at 250 kcmil and above. This is a planning weight for the order, not the utility's reel. Confirm 310.12 and the utility spec before you buy the lateral.
Code reference
NEC Table 310.16 and the serving utility specification. Dwelling service reductions in 310.12 are not applied automatically.
Field questions
- Why is the run only 50 feet?
- Service laterals are short, so the lesson is ampacity and coil weight, not a long-run voltage drop.
- How is aluminum weight estimated?
- The same-size copper weight is multiplied by 0.33. It is an allowance for the lighter metal, not a mill certificate.
- What if two parallel sets are recommended?
- The note will say so. Weight and cost both use the set count. Paralleling has its own NEC rules.