Go direct to your local search engine on your mobile or desktop computer and, sure enough, you will be able to locate a guide book on regulations pertinent to your area or county. You will also be able to tap into regulations that are enforceable across the state. Call it house rules for your business, but there will be rules that your dc commercial electric services provider should be obliged to follow. And good that you studiously went through the guidebook.
But then went right back to your workshop or your house and tampered with the wires anyhow. That just goes to show that you did not read through the basic rules of what to do and what not to do with electrical installations. Understandably, and good that you have these, you may have concerns. But you need to understand and appreciate that those domains that you are powerless to handle are best left to the electrical contractor, provided of course, that he is a registered and regulatory recognized service provider.
DIY enthusiasts who think themselves quite handy and useful around the house may turn out to be a jack in the box of a different kind. Tamper with those loose wires just once more and you could find yourself blowing more than a fuse. This is always dangerous. Only qualified electricians have any business going behind circuitry boards, detaching them and rewiring them. Leastways if you allow them to get on with their work they do know what they are doing.
And if they are licensed and registered, they are more than likely accredited too. By the regulatory authorities no less. And you can be sure too that they know all the rules and regulations. Off by heart.