I'm running #6awg indoor cable for a battery back up. The electrical room is 100 ft away. What is the code? Do I need to run it in conduit in a commercial building? Or can I run the cable without conduit?

Sorry for the delay in responding.

We need some help here. Your term, "Indoor wire" is to vague. We need to know the type of cable being used. It should be printed on the outside of the sheath.

Just curious, are you a licensed electrician? I ask because most states require that you be licensed before you can do commercial electrical work. Unless you have been trained on the equipment. For example an alarm company installer.

Daniel, this is a risk reward thing...if you try to do this and you do it wrong, what will be the cost?
Is this cost high enough to hire a professional to do it correctly the first time?
(sounds like you could use help)

Your cable description needs to be a bit more specific. For example, in some installations you may use shielded cable without conduit, unless there is a risk of damage, then you could run it partially within the pipe. Local codes also govern cable protection and installation requirements, as well as the NEC issues. It is however your responsibility to make sure it is done correctly.