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What Size Wire for 100 Amps at 150 Feet?

At 150 ft, a 100 A feeder changes character: the default result upsizes to 2 AWG copper or 1/0 AWG aluminum because voltage drop, not termination ampacity, governs.
Load
100 A
Distance
150 ft
Band
100 A feeder
Defaults
Non-continuous, 75 C lugs, 86 F, 240 V single-phase

Computed Starting Point

Ampacity and voltage drop under common defaults for this amp and distance.

MaterialComputed sizeOCPDUsable ampacityGoverning constraintDefault check
Copper2 AWG100 A115 AVoltage dropPasses defaults
Aluminum1/0 AWG100 A120 AVoltage dropPasses defaults
What Size Wire for 100 Amps at 150 Feet? under common non-continuous defaults: THHN or XHHW-2 insulation, 75 C terminations, 86 F ambient, 240 V single-phase and no more than three current-carrying conductors.

What 150 ft ChangesAt 150 ft, voltage drop becomes the governing constraint for both materials under the page defaults. That means the extra conductor size is buying voltage performance, not extra breaker capacity. If the measured route is actually closer to 100 ft, the previous page may hold; if it is closer to 200 ft, plan for another jump.

Run the wire size calculatorCheck voltage drop alone

Zero-Length vs This Distance

If the distance-adjusted size is larger, voltage drop governed under these defaults.

CaseCopper sizeCopper constraintAluminum sizeAluminum constraint
Ampacity only (0 ft)3 AWGTermination rated 75 C1 AWGTermination rated 75 C
150 ft (this page)2 AWGVoltage drop1/0 AWGVoltage drop
Copper and aluminum sizes for 100 A with no distance entered versus 150 ft one-way.

Adjacent Distances at This Amp

Neighboring published lengths for 100 A under the same defaults.

DistanceCopper sizeAluminum sizeCopper constraint
100 ft3 AWG1 AWGTermination rated 75 C
150 ft (this page)2 AWG1/0 AWGVoltage drop
200 ft1 AWG2/0 AWGVoltage drop
100 A copper and aluminum starting sizes across neighboring distance pages.

150 ft Is the First Jump Length

100 A feeder context for 100 A at 150 ft.

A 150 ft 100 A run is the classic detached garage or shop feeder where the straight-line distance looked safe, but the measured conductor path is long enough for voltage drop to take over.

This page is not just the 100 ft answer with a different number. Under the same defaults, both copper and aluminum move one size above the zero-length result, and the next 200 ft page moves again.

What Changes This Long-Run Answer

Checks that matter for distance-governed sizing in this amp band.

  • Measure the installed route

    A trench that looks like 120 ft on the plan can become 150 ft after panel location, sweeps, risers and equipment offsets are included.

  • Do not reuse the 100 ft conductor

    Under these defaults, 100 ft is termination-governed while 150 ft is voltage-drop-governed. The smaller 100 ft answer is not the same page.

  • Check 200 ft before buying

    If the final route may grow, price the next distance before ordering. The adjacent table shows another conductor jump at 200 ft.

  • Separate drop from ampacity

    A 2 AWG copper or 1/0 aluminum result here does not authorize a larger breaker. It is still a 100 A feeder answer under the stated defaults.

100 A at 150 ft FAQs

What size wire for 100 amps at 150 feet?
Under the defaults on this page, the starting result is 2 AWG copper or 1/0 AWG aluminum. Voltage drop is the governing constraint for both materials.
Why does 150 ft change the 100 A wire size?
Length does not change ampacity, but it does change voltage drop. At 150 ft in this default 240 V model, drop forces an upsize from the zero-length 100 A result.
Is 150 ft too far for a 100 A feeder?
Not automatically. It is far enough that voltage drop has to be checked, and under these defaults it changes the conductor size. The real route, voltage and load profile still decide.