Electricians who fail the Texas electrical exam are able to retake the test as many times as they need until they pass. This may not be the most economical way to get your license, but it can be done. PSI exams will allow you to sign up for your re-test as soon as you need to.
Here are some things to keep in mind when you attempt to retake your electrical test:

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You will have to pay for the exam each time you take it.
This is why we strongly suggest you invest in an electrician exam prep program. A study program for the electrical exam will help you learn what you need for the electrical test and you have a greater chance of passing the test on the first attempt.
There is no waiting period.
You can reschedule your test as soon as you want. We strongly suggest you take the test within the next 7 days while the test is still fresh in your head.
Keep your Score Report from the first failed exam.

It’s important to hang on to these “fail” score reports that PSI gives you after your exam because we can tell you exactly what to focus on based on that score report.
This diagnostic report will break down the categories of the questions you missed which will help tell you what to study for the retake.
If you didn’t take a prep course or practice exam before, now is the time to do it. Learn more about this electrical practice exam program with questions like in the exam and also breaks down your results just like the test. This way you’ll see your improvement before you go sit for the real deal.
Finally, don’t get frustrated and don’t quit. 
I’ve seen guys just a point short of passing and I know it’s frustrating but hang in there. You’ll get it.
You can always find all of the rules and procedures on PSI and TDRL.

Texas Department of Licensing and Regulation

PSI Exams Online