Return to electrician calculators

Standard Size Calculator
for Fuses and Circuit Breakers

Section 240-6(a)
(Size up or down allowed
for 800 amperes or less.)
(Size down above 800 amperes)
Select Option
(see Note below)
Size Up
Size Down
Enter Amperes
Notes: (1) Size down for conductors
that are part of a multioutlet
branch-circuit supplying
receptacles for cord and
plug connected portable loads.
(2) Additional fuse sizes
of 1, 3, 6, 10, and 601 amperes
are not included.
Fuses can be manufactured
to almost any size.