Dry Stacked Block Wall Electrical Considerations

Main power distribution

Start with electrical supply. I have an outside electrical meter and main disconnect switch as shown below. Then a 200A service cable carries the power from the disconnect switch over to the house circuit breaker. As seen in the left picture, my electric supply via underground cable enters the bottom of the main disconnect switch panel. The switched leaves the top of the switch panel and passes through PVC conduit in the attic to the indoor circuit breaker box pictured on the right.

The circuit breaker panel is recessed into the 2-inch wall insulation, the 1×4 mounting boards (actually 3/4-inch thick) and the 1/2-inch sheet rock. This adds up to a 3-1/4-inch box recess. I then added a 1/2-inch plywood sheet between the sheet rock and the recessed circuit breaker panel. This results in 3-3/4-inch breaker box recess which allows the breaker box cover to remain flush with the surface of the plywood as seen in the pictures. This plywood panel also allows access to the cables into and out of the circuit breaker panel top.

My TV antenna cables and telephone cables are also located next to the outside disconnect switch box for easy connection to the required earth ground stake near the disconnect switch box. This disconnect switch box also contains circuit breakers to feed a 60A service to my work garage.

House power distribution

All house power cabling exits the breaker panel vertically up into the attic. Each cable drops down from the attic to the switch or outlet box. The cable is buried in the wall insulation foam and exits the foam at the desired location. This location will have a 1×6-inch board screwed to the wall and the box is installed in that board. Box mounting brackets extend the box face 1/2-inch beyond the 1×6 board so the box is flush with the sheet rock.

Dry stacked block wall electrical considerations picture.
Dry stacked block wall electrical considerations switches.

As shown in the picture below, with multiple ganged switches you have to use a horizontal 1×6-inch board. I also place the kitchen counter top electrical outlet boxes in horizontal 1×6-inch boards because the outlet location didn’t line up with the vertical boards holding the foam in place. Here you can also see where I mounted the vertical wires going into the attic within the rigid foam and place foil tape to keep them in there.

Dry stacked block wall electrical installation picture.

Wiring common electrical precautions

I have found through bad experience a problem the electrical code does not address. It has to due with wire dressing inside the electrical box. Codes require about 6-inches of wire excess within each box. Code also requires a loop of wire outside the box. Check with you inspector on these two issues so you meet code when finished.

The excess wire inside the box must be dressed properly. Prevent the black wire from pressing against the ground wire and/or the white wire which may also be common. When the black wire is presses against the ground wire or white wire, it will become a short over time. The black wire insulation is pliable and the conductor will penetrate the insulation and cause a short circuit when constant pressure is applied. Ensure the black wire is never pressing tightly against any other wires inside the box, nor touching the sides of a metal electrical box.

Another possible electrical short

Another problem I ran into was a short inside the actual wire as it came off the 500-foot spool. After the sheet rock was installed and power applied, one circuit had a problem. It kept tripping the circuit breaker. After checking with a milli-ohm meter I determined that the short was near the associated light switch. I had to cut open the sheet rock to find the short within the new wire cable about 3-feet above the light switch.

I installed a junction box to remove that section of wire that was shorted. Because of this I now recommend that you check for wire shorts before installing the sheet rock!

For more info on residential electrical code, start here.

Dry stacked block wall electrical installation typical plan.