I'm on the customer end and we have one contractor that consistently keeps 10 electricians at the plant, right now it's closer to 25 because they have a lot of work. None of this is maintenance work, all new projects. Works well for me because I can issue a $5,000 contract as easily as a $500,000+ contract and not have to pay for mobilization, safety training, an hour of pipe bender here, 2 hours of JLG there, etc. Three benders, a threader, a few JLGs, scissor lifts, trucks, etc. are all on site and ready to go. The contractor of course keeps the same core group that knows the plant better than some of the employees. We still retain the flexibility of issuing large contracts to the same superintendent and project manager we always deal with and they can bring in additional personnel as needed. One thing to keep in mind is that loyalty may be built more toward the customer than the EC - this will vary depending on the situation but you're likely to have people jumping to work for the customer if that is a possibility.