Short answer. Only partly. Rule 39, Section 13 exempts your earnings for personal services in the four months before the levy, but only as are necessary for the support of his family. Pay beyond what the family genuinely needs, and pay outside that window, can be reached.
What the law says
So much of the salaries, wages, or earnings of the judgment obligor for his personal services within the four months preceding the levy as are necessary for the support of his family
Rule 39, Section 13 — Property exempt from execution. Read the full provision →
The exemption is a slice, not a wall
People often assume salary cannot be touched at all. The rule is narrower than that. Section 13 exempts so much of the salaries, wages, or earnings as are necessary to support the family — a quantity, not a category. Everything above that line is ordinary property and can be applied to the judgment. So the practical question is never "is my salary exempt?" but "how much of it is needed to keep my dependants fed, housed and schooled?" That is a factual question about your household, and the person claiming the exemption is the one who has to make it concrete.
Two limits built into the clause
First, the earnings must be for personal services — pay for your own work. Income that is really a return on capital, rent, or business profit is not what this clause describes, however it is labelled on paper. Second, only earnings within the four months preceding the levy are covered. Wages that accrued earlier, or savings that have already left the character of current earnings and sit in an account as accumulated funds, fall outside the words the rule uses. The exemption is designed to protect current subsistence, not accumulated wealth.
What "necessary for the support of his family" means in practice
The rule does not fix a percentage, and no honest answer can invent one. What it asks is whether the amount is needed for the family's support — food, housing, utilities, schooling, medicine and the like for those who actually depend on you. A worker earning close to subsistence may find nearly all of it protected; someone earning far above the household's needs will find the surplus exposed. Expect the creditor to test the claim, so household figures should be capable of being shown rather than asserted.
The exemption still has to be claimed
Section 13 lists what is exempt; it does not make the exemption apply by itself, and it does not tell the sheriff how much of a particular pay cheque your family needs. If earnings are garnished, the exemption and the supporting facts have to be raised. One further trap sits at the end of the section: exemptions do not apply where the judgment being enforced is for the price of the exempt thing itself, or on a foreclosure of a mortgage over it.