329Deductions from earnings not to exceed earnings
(1)The amount of a deduction allowed under this Part may not exceed the earnings from which it is deductible.
(2)If two or more deductions allowed under this Part are deductible from the same earnings, the amounts deductible may not in aggregate exceed those earnings.
(3)If deductions allowed otherwise than under this Part fall to be allowed from the same earnings as amounts deductible under this Part, the amounts deductible under this Part may not exceed the earnings remaining after the other deductions.
(4)Subsections (1) and (2) do not apply to a deduction under section 351 (expenses of ministers of religion), and subsection (3) applies as if such a deduction were allowed otherwise than under this Part.
(5)This section is to be disregarded for the purposes of the deductibility provisions (see section 332).
(6)See also section 380 of ICTA (which provides that where a loss in an employment is sustained, relief may be given against other income).