What Is A Main Panel Upgrade (MPU)

What Is A Main Panel Upgrade?

WHAT – A main panel upgrade (MPU) is a new main service panel (MSP). The MSP is the meter panel located on the side of your home where all of your individual branch circuits are located. It is also the point of interconnection with your utility company. Remember when the bathroom lights flickered and turned off because the hair dryer and straightener were on at the same time? The MSP is where you went to reset the breaker.

WHY – When going solar, main panels are upgraded for numerous reasons often boiling down to the size of the solar and battery system. Most MSP’s are limited to 40 amps of over production – often called the “120% rule”. The 120% rule explained: 200 amp rated MSP x 120% = 240 amps, less the main breaker of 200 amps leaves 40 amps for solar. If a solar system is rated to generate anything more than 40 amps, the main service panel will need to be upgraded (or DeRated – see next blog post).

Another reason for an MPU is the existing electrical hardware in the house is simply not fit for solar. This includes aging hardware, failing hardware, inadequate space for the solar and battery, etc. Also, a main panel upgrade is a great way to future proof your home for future electrical needs. The world is rapidly becoming more electrified and homes do not have adequate electrical hardware or amperage in place to service modern electrical systems. Just think about adding two electric vehicles in the next decade and how that might have an impact on a 50 year old MSP.

HOW – Our in-house staff conducts a detailed load calculation and analysis. This is done so we have a clear idea of the need and ultimate scope of the MPU. Sunriver Solar then works with your utility company and building department to get the appropriate permits and approvals prior to the MPU. A date will be scheduled with the utility company to turn off your power. Sunriver Solar will be on site the same day to remove your old main service panel and install the new one. All circuits will be wired in an appropriate manner per building code. A building official from the county building department will then inspect the work (same day) and sign off and place a green tag on the new main panel. After the work is inspected and “green tagged”, Sunriver Solar will call the utility company to have them turn your power back on. An MPU can be completed in half a day. However, we always tell our customers to plan for a full day without electricity because so many independent, busy, parties are involved.

WHO – Any solar customer can be a candidate for a main panel upgrade. If you are evaluating your own solar project and it aligns with the information above, you are likely a strong candidate for a main panel upgrade. Please be sure to ask your solar provider any questions. Be sure you understand the amperage rating of the new main service panel, the number of circuits that can be installed, and WHY an MPU is even necessary in the first place. Note that not all solar customers need an MPU, so ask questions.


Leave A Comment

Working hours
Monday 7 AM–4:30 PM
Tuesday 7 AM–4:30 PM
Wednesday 7 AM–4:30 PM
Thursday 7 AM–4:30 PM
Friday 7 AM–4:30 PM
Saturday Closed
Sunday Closed
Our location
Social profiles