First, make sure you know all the current needs. Are you just doing to electrical infrastructure, or ALL of it. Who else is providing input to your boss? There are certain groups that will have higher priority in the building design, such as Safety & Occupational Health, Human Factors, etc. Make sure these are covered BEFORE you start planning. You don't want safety to throw up a flag if you need a power box near an eyewash station.
Next, ask what is in the business pipeline for the near and far future. You may know some of these, but not all of them...
Check industry vendors to get an idea of where the future of CNC equipment you may be using is going. What infrastructure will be needed to support these capabilities? How will the workfloor change to accommodate these machines?
Bearing these in mind, scope up your desired infrastructure. Keep in mind:
a) Boss may not be able to afford everything. Make sure it is possible to scope back your design. Be sure to also know and communicate what risks become more likely if the scale-down is needed. There will also be compromise if multiple designers present conflicting designs.
b) Remember your *ilities. Make sure changes can be implemented, because maintenance, breakdowns, and logistics happen and the world has revolutionary changes that nobody expects.