70-Amp Dual-Pole Circuit Breaker for PV Systems
Scope
To construct a home that is Renewable Energy Ready and prepared for the installation of a future solar photovoltaic (PV) system:
- Include a dedicated 70-amp dual-pole circuit breaker
- Place the circuit breaker panel box near the future balance of system components for the PV.
- Consider space requirements and layout within the home and on the roof for solar photovoltaic system components early in the design process.
See the Compliance Tab for related codes and standards requirements, and criteria to meet national programs such as DOE’s Zero Energy Ready Home program, ENERGY STAR Certified Homes, and Indoor airPLUS.
Description
A renewable energy-ready home (RERH) is one that is built with the wiring and plumbing conduit and other components in place to facilitate the future installation of solar photovoltaic (PV) panels and/or solar water heating panels. Some energy-efficiency programs, like the U.S. Department of Energy’s DOE Zero Energy Ready Home Program, require homes to be renewable-energy ready.
To prepare for a future PV system to be connected in a home, install a dedicated double-pole circuit breaker in the electrical service panel or in a separate subpanel. The breaker is intended for protection of the PV modules and wiring from reverse current flow. The breaker should be appropriately sized for the PV array that is being installed.
How to Install a 70-Amp Dual-Pole Circuit Breaker
- To meet the requirements of the DOE Zero Energy Ready Home program, designate a dedicated space in the electrical service panel for a dual-pole circuit breaker.
- Hire a licensed electrician certified by the local jurisdiction to install the electrical equipment associated with the electrical service panel.
- Label each breaker in the service panel with water-resistant labels. The breakers dedicated for the future PV system should read, “Renewable Energy Ready Home – Solar PV Dedicated Breaker.” See Figure 1.
- Record the location of the future PV system and all of its components on relevant architectural diagrams to be provided to the homeowner.
Ensuring Success
Ensure adequate space in the electrical service panel for a dedicated dual-pole breaker, early in the design process. If possible, place the circuit breaker panel box near the future balance of system components for the PV. Confirm with local code officials early in the design process what steps are needed to guarantee that installation of PV panels will meet with local codes, homeowner's association covenants, and historic district regulations.
Protect the electrical and mechanical components of the PV system from bulk moisture, high temperatures, and direct sunlight. The utility room should be properly ventilated and maintain average indoor temperatures. Proper clearances and working spaces should also be maintained.
Climate
DOE Zero Energy Ready Home
Builders seeking to qualify a home to the DOE Zero Energy Ready Home specification are required to meet the requirements of the DOE PV-Ready Checklist, including installation of a 70-amp dual-pole circuit. Builders are exempt from the requirements contained in the PV-Ready checklist if the location, based on zip code, has less than 5 kWh/m2/day average daily solar radiation based on annual solar insolation using the PV Watts online tool. See the Compliance tab for additional exemptions.
Training
Presentations
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Organization(s): DOE
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Compliance
The Compliance tab contains both program and code information. Code language is excerpted and summarized below. For exact code language, refer to the applicable code, which may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.
DOE Zero Energy Ready Home (ZERH) Program
The DOE ZERH PV Ready Home (RERH) Checklist states
Install a 70-amp dual pole circuit breaker in the electrical service panel for use by the PV system (label the service panel) (RERHPV Guide 3.4)
Alternative: Provide a labeled slot for a double-pole breaker in the electrical service.
DOE Zero Energy Ready Home National Program Requirements Mandatory Requirement 7 (Renewable Ready) shall be met by any home certified under the DOE Zero Energy Ready Home program, only where all of the following conditions are met:
- Location, based on zip code has at least 5 kWh/m2/day average daily solar radiation based on annual solar insolation using PVWatts online tool, AND;
- Location does not have significant natural shading (e.g., trees, tall buildings on the south-facing roof, AND
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Home as designed has adequate free roof area within +/-45° of true south as noted in the table below.
Table 1. Minimum roof area within =/-45º of true south, compared to conditioned floor area
Note, if a solar photovoltaic system is included with the home, then compliance with the Consolidated RERH checklist is not required.
These requirements were adapted from the EPA’s Renewable Energy Ready Home Solar Photovoltaic Specification Guide (RERHPV Guide). For further guidance on any of the above items, this checklist notes the section of the guide.
2009, 2012, 2015, and 2018 IECC
Section 401.3 A permanent certificate shall be posted on or near the electrical distribution panel that lists types and efficiencies of water heating, heating, and cooling equipment, as well as insulation R values, and window U and SHGC factors.
Retrofit:
Section R101.4.3 (Section R501.1.1 in 2015 and 2018 IECC). Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing building to comply with this code. (See code for additional requirements and exceptions.)
2009, 2012, 2015, and 2018 IRC
Follow the requirements for solar water heating systems found in the 2009 IRC Section M2301 Thermal Solar Energy Systems (Solar Systems in IRC 2009).
Retrofit:
Section N1101.3 (Section N1107.1.1 in 2015 and 2018 IRC). Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing building to comply with this code. (See code for additional requirements and exceptions.)
Appendix J regulates the repair, renovation, alteration, and reconstruction of existing buildings and is intended to encourage their continued safe use.
2009, 2012, 2015, and 2018 International Mechanical Code (IMC)
Follow the requirements for solar water heating systems found in the IMC, Chapter 14, Solar Systems.
2014 National Electric Code (NEC)
Follow the requirements for solar photovoltaic (PV) systems found in the 2014 National Electric Code (NEC), Article 690, PV Power Systems, and Article 110, Requirements for Electrical Installations.
More Info.
Access to some references may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.
Solar Electric Ready Home = Solar Electric Ready Home
As solar photovoltaic (PV) panels come down in price, many homeowners are installing them to produce clean power and reduce their electric bills; many more homeowners are likely to want to in the future. To make it easier for homeowners to add solar electric panels in the future, builders of new homes can take steps while the home is during design and construction. At that time electrical wiring and conduit can be installed, the electric panel can be selected to ensure it has adequate space for the PV circuit, the roof can be constructed to handle the extra weight of the PV array, the home can be designed to ensure it has adequate roof space that is not shaded, and space can be provided near the electrical panel for shutoffs and inverters. The U.S. Department of Energy’s DOE Zero Energy Ready Home Program requires homes to be renewable-energy ready to receive a program label.
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