I work in the media. Tends to vary where you go but casual to business casual is the norm. Just don't come to work looking like a slob is the norm. I tend to dress business casual. Only the big wigs dress formal.
On the job site.. its Fire retardant coveralls, hard hat, steel toe boots, saftey classes.. plus additional safety stuff as required.
When i go to the office.. ususally jeans and either t-shirt or a polo. Depends on what i'm doing there.. If i assist our tech group.. jeans and t-shirt.. if i work on final job paperwork..i'll wear jeans and polo. Normal office staff wear business casual.
No code per se, but I always wear chinos and a collared (Land's End) type of shirt.
I would not go in with clothing that is all in tatters or ripped. As to jeans, they do allow them, but I prefer only very soft denim, which is getting harder to find.
I'm a lawyer and have my own firm. I am in court pretty much every day, so therefore I wear a suit and tie every day. I decided to go business casual on Friday a few months ago and got busted by one of the senior Judges for not having "proper attire for a lawyer". I was filing papers with the prothonotary on a Friday afternoon. Oh well, at least I can take my tie off when i am in the office.