What is the law concerning Exempt employees working outside of their job category? My organization is a sub-contractor. The prime wants to cross-utilize employees on the work effort.

They, the prime, plan on requiring the "subs" to cross utilize our personnel to assist on hourly non-exempt work. If we do that my understanding is that it cannot be more than 10% of the total time within the pay period. I am I correct?

The 10% is not a hard and fast one. You need to look at the whole picture and the totality of the individual's duties and responsibilities. The classification would also not change pay period by pay period.

Let's see if I can ask the question with more clarity. If I have 50 Exempt employees, how much of their time can I have them engaged in doing non-exempt employee work.

I have a team of analyst(exempt) that are going to be required to execute the duties of an electronic technician's (SCA, non-exempt hourly employee) work.

There is no set time limit. If their duties are totally changing over to nonexempt ones, then obviously you need to reclassify them. If they are just pitching in to help with some of the tasks nonexempt employees perform, but retaining their exempt responsibilities then they can remain exempt. There is no hard and fast rule that says after they perform X number of hours of nonexempt work they must be treated as nonexempt.

If it isn't clear call the DLSE and get their opinion.

got it, thank you

One other thing. The question sort of assumes that each and every one of these currently Exempt employees is spending 100% of their current job doing nothing but Exempt tasks. I have never seen an organization where that was true. What the OP is really talking about is adding more Non-Exempt tasks to those NE tasks that the Exempt employees are already performing. At some point a "tipping point" occurs and the Exempt employees are no longer Exempt, either for the current pay period, or for more or less permanently. That tipping point will occur differently for each employee because each employee currently has a different mix of Exempt and NE tasks associated with their current job. And the risk is that a disgruntled employee will file an overtime claim with state DOL.

The Exempt classification is determined by looking at all tasks performed by the employee. The employer can pretend that there are two different jobs involved if they want to, but that is not how the law looks at it.