I have a small florescent light in my kitchen. I am going to replace it because the cover is broken. I noticed they did not have an electrical box behind it. It is just attached with butterfly anchors. I'm guessing it doesn't have a box because the electrical connections are made inside the light fixture. I'm debating on whether to replace it with a similar light or buy a vanity type light. Should I add a new work electrical box?
Unless the new fixture completly encloses the wire splices like the original one did, you need to add a Jbox. Splices need to be contained in a fire resistant enclosure because they are the weak point in the system.
If the wirenut splice becomes loose it will arc, spark and cause a fire. If this happens, you want to contain it.