Problem: Sound and noise leaking through electrical receptacle / switch / outlet / boxes.
Cause: Unsealed, back-to-back electrical receptacles as shown in Figure 6a.
Figure 6a - Unsealed Back-To-Back Electrical Boxes
- Offset the receptacles from each other along the wall at least 16 inches (400 mm) as shown in Figure 6b. Keep holes as small as possible. Seal the openings with acoustic sealant. Insulate the cavity, including behind the electrical boxes.
Figure 6b - Offset Electrical Boxes
- In existing housing, seal the outlets as much as possible if they have already been installed, or use foam gaskets. If necessary, open up and block off with dense insulation and sealed blocking.
- Extend internal blocking to guard against leaks around electrical boxes and at the foot of a double stud wall.
- Use sound-absorbing materials inside walls and floors as shown in Figure 6c. The structure can be designed so that leaking sound must travel through a great deal of sound absorbing material.
Figure 6c - Use Sound Absorbing Materials Between Electrical Boxes.
It should be noted that the installation of back-to-back electrical boxes as shown in Figure 6a is the easiest method for the electrical contractor and hence is the least expensive. So, the method shown in Figure 6a is most common. Very few architectural plans will specify any back-to-back separation between electrical boxes.