Factual error: Several problems surround the electrocution death and the investigation. First, there is the insinuation that the boots should have protected the victim from the electrocution because of the rubber soles. Regular shoes and standard work boots will not protect anyone from electric shock. You are still grounded. You have to wear special electrician's boots to insulate you from electric shock. These boots cost about triple standard work boots. Second, the CSI crew found a nail embedded in the boot. They theorized that is how the boots were grounded out. The problem there is the nail had to be pushed all the way through the sole and through the insole for it to work (the close up of the boot showed the nail in all the way). Even if the nail was barely through the insole, the victim would have felt the nail poking him at every step. With the nail all the way through, he wouldn't have even walked two steps before puncturing his foot on the nail. Third, there is the nail itself. When Grissom is examining the boots trying to find why they failed (failed to prevent the electrocution), he poses the question "What is the most common item found during construction?" The answer is a nail, and the nail in the boot appears to be a roofing nail. The construction site is for a multi-story prison. Nails aren't used in the construction of multi-story urban buildings: concrete and steel are. Carpenters come in after the building is erected and work on the interior, but there are no roofing nails.
Factual error: In the episode where the worker got electrocuted in a construction site the main character, before replaying the victim's fall, says that "terminal velocity is 9.8 seconds squared". What he should have said was that acceleration due to gravity is 9.8 meters per second squared.
Factual error: When they are explaining why a nail was hammered into the electrocuted workman's boot, it is said that cars are protected from lightning strikes because they are insulated from the ground by their tires. Actually, tires conduct electricity, because they contain carbon (see: http://cartalk.cars.com/Columns/Archive/1994/November/11.html). Cars are actually protected from lightning by the Faraday Cage effect, which is explained on http://www.physics.gla.ac.uk/~kskeldon/PubSci/exhibits/E3/. Not a mistake CSI scientists would make.
Factual error: Grissom sets up a little experiment to see if the deceased's blood is conductive to electricity. All are amazed when the blood does conduct electricity. All blood is naturally conductive. As a matter of fact, cardiac output is measured as a function of blood conductivity.
Answer: He doesn't have the authority to arrest him - when anyone is arrested in the show, a police officer does it. Also he tells Ty that he is going to be submitting his case findings to Ty's insurance company, who would no doubt contact the IRS, who then would have him arrested for fraud etc.