ElectricalAdvice

Rough-In Continued

With the home runs installed, the panelboard installation is almost complete. We have the panelboard mounted in the wall, roughly 60" to the center off the finished floor. This allows for easy access to everyone for utilizing the circuit breakers when necessary, such as a problem with a tripped circuit breaker. Tripping circuit breakers due to overloaded circuits should not happen in a new house, it is the electrician’s job to ensure that overloaded circuits not occur at any time, for any reason, with the designed-in-place circuitry he crafts. But they sometimes do and for that reason, and the safety of the maintenance people, there are a whole set of do’s and do not’s for the electrical panelboard installation and related service equipment.
An area designated as space for the electrical panelboard must have these attributes:
An adequate horizontal space (side to side) of not less than 30", or 2'-6". The panelboard can be mounted anywhere within this 30" horizontal space, although in most cases it is mounted near the center of this space. Above and below the actual foot-print of the panelboard a space of 14-1/4" or greater width, by the depth of the panelboard enclosure itself (usually 3-1/2" - 4") is reserved space for the electrical wiring. In this zone, which extends from floor to structural ceiling, no other system is allowed to penetrate or pass through this space. That means no heating ducts or pipes, no plumbing pipes, no vacuum system pipes, no telephone or alarm wires, no cable tv wires, or speaker wires, notta thing, Nuttin! But that is not all.
For the safety of the installer, the maintenance people and the homeowner, working space for panelboards and other electrical device and/or equipment installation is such:
In the space from floor to structural ceiling in the area defined as 30" (2.5') wide and 36 inches (3') deep and 80" (6.5') there shall be no other obstructions to the electrician (or anyone for that matter) working on a panelboard installation. If a usable space for the panelboard is available that meets the 6.5' height clearance requirement, it is best to utilize it. NO other obstructions is a reference to any bookshelves, desks, work benches and the like, that could be built under, or around the electrical equipment. No Can Do!
The thinking is that the user, leaning over a work bench or bookcase is in peril of falling into the live electrical parts, left exposed while under going any number of electrical tasks, including testing and resetting a blown circuit breaker. The idea is to allow the person room to stand in front of the equipment without banging his head, bending over, or squatting on one knee. Logical, don’t you think?
The next item that we consider for installation on the electric service, is the device that keeps track of all of electricity you use in your household, the receptacle if you will, for the electric meter. This socket, described as having two line and two load terminal jaws, or opposing parts that close to hold fast a connection between itself and the flat spade terminals of the electric meter, and a terminal buss for the Grounded or Neutral Conductor. These meter sockets or pans as they are also known to some, are rated for voltage and amperage, for residential work the most common are 100 amp and 200 amp versions and sometimes in the bigger homes a 400 amp model.
Housed most often in a steel enclosure, usually raintight since it will be mounted on the exterior of the building, or out in the weather. Line and Load lugs (connection tabs) are mounted on an non-conductive ceramic yoke to keep them insulated from the grounded connection made at the neutral buss, which is fastened directly to the steel enclosure. The two top terminals are the Line or the street side of the electric meter, the two bottom terminals are the load side. The neutral conductors are not metered, the connection for the neutral is made on a two-terminal strip, as mentioned, which is fastened to the steel enclosure, making it part (electrically) of the grounding electrode system. For the purpose of an additional connection, there is an additional lug on the neutral buss, for the connection of the grounding electrode conductor.

Photo / Meter Socket

Since we sometimes do overhead cables to the street for power, from a telephone pole and we sometimes do underground cabling to a pole, a hand hole or transformer vault, the raintight meter enclosure must be adaptable for these two uses. Some companies make a single, overhead meter socket and sell you a blank plate to use when you are going underground and don’t need the top knockout; others make both an overhead and underground socket for each use.
In the overhead version of the socket, there is a large hole at the top of the enclosure which will have four mounting holes for the meter hub, or raintight collar; which at once closes in the gaping hole and allows a threaded hub for the insertion of a rain tight PVC connector, or terminal adapter.

I use Poly-Vinyl-Chloride (PVC) Schedule 40 conduit for all of our service installations, it allows for a better installation, with longevity in mind. Also, when you have to re-shingle, or re-side your home, the conduit is much easier and safer for the subcontractor, be they roofer, siding installer, or painter. At this point in our house, I will use the 2" PVC, Schedule 40 conduit between the panelboard, located in the laundry / back entry, to the meter socket, located on the back of the house.

The panelboard is mounted between two wall studs, on an interior partition, this mandates that I enter the enclosure from the bottom, and shoot outdoors through and within the wood stud wall, with the 2" conduit. Directly below the panelboard, I glue a male terminal adapter (fancy word for 2" PVC connector) on a 90 sweep fitting. Adding a lock nut and plastic bushing inside the enclosure I tighten fast the lock nut with a screw driver and a hammer. Turning the 90 sweep to face the opposing stud, in this case to the rright or outside of the building I mark the centerpoint of the sweep end, and bore a 2-9/16" hole. I continue boring 2-9/16" holes through adjoining studs until I reach the exterior sheathing and stop. With a smaller, 1/4" drill bit, I continue boring through the exterior sheathing and shingles or clapboard siding, until I am through all of the material. I can then locate, on the exterior, where that 1/4" bit came through, lining up a pilot bit for a 2-9/16" hole saw to continue the larger size through the last of the siding and sheathing. By doing this, we eliminate tear-out of the shingles, caused on the outside of the house from the brawn of the larger, more destructive wood-boring bit. It may be necessary to adjust the height of the horizontal holes for the conduit so that they better match the position of the hole and it’s relation to the shingle courses on the outside of the building.
All this done, we can then calculate the size of the grounding electrode conductor, and the bonding jumper for bonding; to make one - electrically, the water pipes and the electrical service ground. One conductor, the bonding jumper, must be sized in accordance with NEC rulings in relation to the size of the service entrance conductors. The Grounding Electrode Conductor is sized according to a prescribed table in alignment with the total amperage of the Electric Service.
In both cases, these cables for the ground and the bond, must be in-place in this service, because the panelboard is mounted on an inside partition and accessing it later on will not be easy, once the finish (wallboard, etc.) is applied.
In our house, for the Bonding Jumper I run a #4 stranded bare copper (as opposed to solid conductor) to a cold water pipe, and I attach it with an approved grounding clamp at the pipe and attach it to the neutral buss in the panelboard. For the Grounding Electrode conductor, because I am using two ground rods for grounding electrodes, I run a # 6 stranded bare copper and attach it to the two rods, unbroken if possible, with an acorn ground clamp and the neutral buss in the panelboard.

Photo of Ground Clamps and Ground Rods