Wiring the Shop - Installing the Electrical Meter Box and Panel Boxes
I decided to hang the meter base and electrical panel boxes on a product that commercial electricians use in most of their installations - Unistrut. This is a great product and allows you to hang boxes almost anywhere on a very sturdy base. Unistrut is made of galvanized
steel and has holes in it so you can anchor it easily and with what is called "spring nuts", you can easily attached electrical boxes or anything else to it.
You will see this being used in most commercial electrical installations. It is also used to hang cables and ducting in industrial installations. I happened to have two lengths of this left over from another installation from a few years back so I grabbed it for this project. I was having to mount the meter base on the side of a tin shop and would have to build something to mount the boxes to. Unistrut is perfect for this outdoor installation. It will not rot or rust and is very strong.
To mount the boxes I used spring nuts and bolts. They make a product that is available at electrical supply places that is not generally known to the public - at least the none commercial electrical installation public. These nuts are designed to work with unistrut and allow you to attach items to this strong mounting base easily. I had seen it used before, but I couldn't think of the name. However, when I went to the electrical supply place, I fumbled around with the description of what I wanted until the guy helping me said, "unistrut" and "spring nuts". They had them in 1/8" and 1/4" sizes, so I went with ten of both sizes. So, if you are wanting to use this great mounting system, remember those names when you go to an electrical supply store. They won't have these at Lowes, by the way.
I used large, strong wood screws to mount the unistrut to the side of the building and mounted my boxes on them. I had to get 2" steel pipe to hook the boxes together and mount the boxes so that they lined up and could connect the two boxes with the steel pipe. The unistrut and spring nuts made this alignment easy.
I had decided that it would be best to pull from the far end of the building for the supply wire from the electric company. They had recommended an eye hook or to be able to pull from the weatherhead pipe. I elected to have them pull from the weatherhead pipe, so that meant I had to anchor that pipe very well indeed. I was able to use the unistrut to anchor the weatherhead 2" pipe as well.
We will see what the electric company thinks of this installation when they get here, but I believe it will hold the 100 ft. line of 3 wire cables up fine.
I also used unistrut to mount the box inside. Remember I said I had an older box? Well, after I had mounted it and ran the wire to it from the outside, I decided to do a continuity test on the main breaker. It didn't pass, so I had to get a new breaker panel after all. I wound up putting in a 100 amp Seimens panel that came with 6 breakers. That should be enough because I'm actually powering the phase converter with the main 200 amp panel on the outside of the building. So, I had to reinstall the inside breaker panel.
I got all the heavy wire ran between boxes. I was able to use the same size wire between all the boxes, even the inside panel, so I have good solid connections between all the boxes of wire that is rated to do the job.
The power company engineer told me to use a de-oxidizing goo on the connections of the aluminum wire that would help extend the life of the aluminum wires. Apparently after 8 or so years, the aluminum will oxidize and the connectivity will weaken because of this. With this product on the wires, it will reduce this from happening on the aluminum wire.
You just coat the exposed ends of the wire before you put it in the connections. You rub it in good on the bare wire and then tighten the wire into place.
With all the boxes in place and the wiring connected, I had one more task to do - installing the ground. The power company engineer made sure to tell me that I had to run a ground - external from the ground they provide from the pole. This ground is a smaller wire - #4 bare copper. It has to be connected inside the meter base - there is a screw just for it. It is also recommended all your boxes be grounded to this wire as well.
The local codes call for the bare copper wire to be attached to a rod that is driven in the ground. These are available at the supply store and can be either galvanized or copper coated solid steel. I got a copper coated rod that was 8 ft. long. Since it has been so dry here, this was going to be a task to drive this in the ground. I started with a homemade fence post driver and it was very effective until the dry ground won out over the welds in the top of the driver and the top came busting out of the top of the driver. I ended up pounding it into the ground with a small sledge hammer, which took about an hour to accomplish getting down to within 10 inches of the ground.
I then had to put the weatherhead on the top of the pole, and wrestling the heavy gauge wire around on top of the shop would have been entertaining for someone to watch. Fortunately, I won the wrestling match and that ended the installation of the power supply installation for the shop.
I double checked all my connections, making sure the ground was in the right place in all boxes and that all connections were tight. I'm glad to be through with dealing with this heavy gauge wire. All the rest of the wiring of the shop should be much easier!
Now to get the power company here.
Make sure you have a good solid installation of your boxes.
Use the correct rated wrie based on your box capacities.
If using aluminum wiring coat the connections with a de-oxidizing agent.
Make sure connections are very tight.
Make sure wires are in correct place.
Make sure your boxes are grounded properly and a ground rod is installed according to local codes.
To the right you can see the completed installation with the ground in place. The interior box is installed inside the shop and is connected directly to the main outdoor panel via an 8" long 2" diameter steel pipe.
I plan to install the phase converter outside the shop to reduce the noise level. It should fit under this panel with a cover to keep the rain out.