Electrical Panel Upgrade

The ability for a home owner to make improvements in their home may depend on the size of their electrical panel. In most jurisdictions the minimum size electrical panel is 150 amps. Many appliances in your home require dedicated circuits. The more appliances one has in their home the larger the panel needs to be. The expression "heavy-up" refers to increasing the capacity of the electrical panel from its current size to a larger size. Heavy-up could also mean changing your fuse panel to a circuit breaker panel. It is important to note there are some home insurance companies that will not insure homes with fuse panels. This is because homeowners could possibly install the wrong fuse (larger) in the fuse holder allowing more current to flow through the electrical circuit. When an electrical wire (eg. size 14awg will carry 15 amps) is over fused and is able to carry more current for which the wire is rated. This conductor could overheat and possibly start a fire. Many appliances are required to be on dedicated circuits so that the circuits will not become over loaded and "trip" the circuit breaker. When the breaker trips it is a safety precaution. It means the wire is carrying more current than what it is rated for and the breaker trips to protect the wire from overheating and fire. Breakers will also trip when the current is shorted to ground.
There are three basic parts to the heavy-up. They are the service cable, the breaker panel and the grounding. All three comprise the heavy-up process and all three are important and must be completed in order for the heavy-up process to be complete. Please remember the heavy-up process will require an electrical permit and only a licensed electrical contractor can obtain an electrical permit from the jurisdiction in which they are licensed. You should ask to see the electrical permit before allowing the contractor to start the work and definitely have the permit before you make the final payment. The service entrance cable (SEC) runs from the top of the house to the power company meter and on to the electrical panel. This wire is rated for the same size as your new electrical panel. If your service is being increased to 200 amps, your service cable must be rated at 200 amps also. The second part of the job is the electrical panel. The electrical panel must have a main breaker. This is to protect the SEC feeding the new panel. The new panel will likely have the ability to hold 40 single pole breakers. This is an important item to check on your contract. Some panels may only hold 20 breakers. Once the panel is full the only way to get additional circuits is to use tandem breakers which are more expensive or to install a sub panel which is substantially more expensive. The 40 space panel is slightly more expensive than a 20 space panel but worth the investment. You certainly want room for future expansion. The last item and possibly the most important of the heavy-up is the grounding. Although somewhat technical I will keep the explanation simple. The grounding system has two basic functions one to protect against lightning strikes and two to protect against faults. The two grounding conductors must be continuous without splice and as short as possible. The first ground is from the electrical panel to a ground rod. Other methods are acceptable but the ground rod is the most popular. The second ground is from the electrical panel to the main cold water cut off connection. Some jurisdictions require the gas line to also be grounded. This is another reason why using a licensed contractor and obtaining an electrical permit is important. In addition to having a licensed contractor who should know what they are doing you will also have an electrical inspector check the final installation.
The final person you will be dealing with is your power utility company. They will make the final connections in the meter socket and at the top near the roof. The cables will be temporarily spliced together by the electrical contractor so you will have power but the power company will make the permanent connections. This process may take a while depending on the time of year and the power company.  Your electrical contractor may be able to help you if the process is taking too long. The temporary splices may be unsightly but the electrical contractor will make them safe. I am sure you will not hurt their feelings if you question him on the safety of the splices.

There are different scenarios in doing a heavy up but the one I have described above is the most common. Of all heavy up scenarios possible the one described above would cover at least 85% of all installations. Another reason to work with a licensed contractor and to obtain a permit is that any deviation from above the contractor would know how to handle the change and the inspector would know what to look for. Always contact your local jurisdiction to find out if the contractor submitting the bid is licensed in that jurisdiction. Remember this is your home and your first priority is safety.