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What Size Breaker for 250 kcmil Wire?

For 250 kcmil wire under the displayed non-receptacle defaults, the largest common breaker is 300 A for copper and 225 A for aluminum. This is a kcmil conductor page, not 250 AWG, and both results require feeder-scale equipment checks.
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250 kcmil
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Breaker Starting Point

Maximum common breaker sizes under common conditions. Derating or receptacle limits can reduce these.

MaterialConductorLargest common breakerAssumptions
Copper250 kcmil copper300 A90 C insulation, 75 C lugs, 86 F, 3 current-carrying conductors, non-receptacle circuit default
Aluminum250 kcmil aluminum225 A90 C insulation, 75 C lugs, 86 F, 3 current-carrying conductors, non-receptacle circuit default
What Size Breaker for 250 kcmil Wire? under common non-receptacle defaults: 90 C insulation, 75 C lugs, 86 F ambient, no more than three current-carrying conductors, and next-size-up checks only where eligible.

What 250 kcmil ChangesAt 250 kcmil, the result is dominated by feeder-scale constraints: lugs, raceway fill, bend space, pulling plan, voltage drop, and service or utility requirements. The page answers breaker compatibility under displayed defaults; it does not turn either material row into a full-load design rating by itself.

Check breaker and wire together

Adjacent Wire Sizes

See whether stepping one conductor size changes the maximum standard breaker.

WireCopper max breakerAluminum max breaker
4/0 AWG250 A200 A
250 kcmil (this page)300 A225 A
Largest common breakers for 250 kcmil and neighboring published wire sizes under the same defaults.

250 kcmil Moves Beyond AWG

kcmil feeder context for 250 kcmil wire.

A 250 kcmil breaker-size search is no longer an AWG branch-circuit question. It usually points to a large feeder, service equipment, a long run, or an aluminum alternative to smaller copper sizes.

Under the displayed defaults, 250 kcmil copper reaches a 300 A maximum breaker through the non-receptacle next-size-up path from 255 A usable ampacity. 250 kcmil aluminum reaches 225 A through the same path from 205 A usable ampacity.

Field Checks for This Wire Size

Checks that matter in this conductor band — not a generic breaker list.

  • Do not read this as 250 AWG

    250 here means 250 kcmil. AWG sizing stops at 4/0, and larger conductors move into kcmil labels.

  • Name both next-size-up steps

    The 300 A copper result comes from 255 A usable ampacity, and the 225 A aluminum result comes from 205 A usable ampacity. Both depend on next-size-up eligibility.

  • Check feeder load and voltage drop

    A large feeder that truly needs the full breaker rating as load ampacity can require a larger conductor. Long runs may also be voltage-drop governed.

  • Confirm large-conductor hardware

    Meter, disconnect, panel, raceway, bending space, and lug kits must accept 250 kcmil in the chosen material before the breaker result is useful.

250 kcmil Breaker FAQs

What size breaker for 250 kcmil wire?
Under the displayed non-receptacle defaults on this page, 250 kcmil copper has a 300 A maximum breaker and 250 kcmil aluminum has a 225 A maximum breaker.
Is 250 kcmil the same as 250 AWG?
No. 250 kcmil is a large conductor size measured in circular mils. AWG stops at 4/0, so 250 kcmil is not 250 AWG.
Why does 250 kcmil copper show 300 A?
The 75 C ampacity path lands at 255 A, which is not a standard breaker rating. With the page's non-receptacle default, the next-size-up path reaches 300 A.
Can I use this page as final approval for a 250 kcmil feeder?
No. Treat it as a compatibility starting point only. Feeder work still needs load calculation, terminal temperature, conductor material, raceway fill, voltage drop, equipment listings, utility requirements where applicable, and AHJ review.