If he makes $300 on my $700 job by collecting $1000, is this a fair exchange?
First, I am not an electrician, although I often do industrial electrical work (wiring motors, PLCs, automation equipment, electro-hydraulic servo drives and feedback devices). I also commission jobs where there may be nothing more than checking things out before having power applied and making start-up adjustments.
I subcontract to several fluid power distributors. They create the job, sell the job, and collect the money. They typically earn (yes, EARN) 30-35% of the invoiced price. They pay me promptly. I do work for them at 10% less than I do on the open market. They give me a 1099 each year. I usually was unfamiliar with the project, often with the customer.
I have seen the cost accounting in their business for many years, and feel that the arrangement is a win for all of us; I get more business and prompt payment. They get customers who universally are happy to have a knowledgeable, experienced, person performing the job ... who can explain the hows and whys of the salesman's and engineer's decisions.
YMMV, but I think they are fair.