I don't wrap mine, but it is a personal preference. Your going to want to go by the internal meat temp instead of time. At 275 they may take a little longer than 4 hours depending on how thick they are. I check mine with a thin instant read therm, and we like them around 195, but if you want fall off the bone ribs then you would want to take them up to 200-205. I also spritz mine with a combo of apple juice & brown sugar every 45 minutes or so. But I have an offset & it will recover real fast. If your electric takes a long time to get back to temp you may want to just forget the spritzing & wrap them in foil after about 3 hours. I use my rub, brown sugar, & butter in the foil along with a little apple juice or water. Leave them in the foil for at least 1 hour or until the IT is around 190 degrees. Then sauce them & either finish them on a hot grill for just a couple of minutes, or back in the smoker for 1/2 hour or so, until you reach the IT your looking for.
Good luck! Check out my PERFECT RIBS Thread in my signature line, it may give you some ideas.
Al