What is all included in a background investigation?

[cole256]

Hi everybody!  I was wondering what all is looked at in your background investigation if you've received an offer to work at an utility?  I already have a nuclear clearance because I'm in a union and I'm actually working at a plant right now.  I have recently received an awesome offer that could literally change my life and to be honest I'm nervous about my credit history.  I don't have a bankruptcy but my credit isn't that great and I'm pretty nervous about it.  Any information would be gladly accepted.  I was also wondering is the in processing of working at an utility the same as when you come in as a contractor?  I have a pretty big phobia of needles I was hoping they wouldn't be involved for drug testing, that it would be a urine sample as usual.  Thanks for your time!

EDIT:  After more thoroughly searching I found a couple of answers about credit