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. 

DOE Zero Energy Ready Home Notes

The U.S. Department of Energy (DOE) Zero Energy Ready Home National Program Requirements includes in Exhibit 1, Mandatory Requirements, Item 7 Renewable Ready, that all homes must meet the requirements in the Consolidated Renewable Energy Ready Home (RERH) Checklist.

The RERH Checklist requires builders to:

  • 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)

 

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

  1. 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.
  2. Hire a licensed electrician certified by the local jurisdiction to install the electrical equipment associated with the electrical service panel.
  3. 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.
  4. Record the location of the future PV system and all of its components on relevant architectural diagrams to be provided to the homeowner.

Electrical service panel with dedicated breaker for future PV system

Figure 1. Electrical service panel with dedicated breaker for future PV system. Reference

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.

Average daily solar radiation per month

Training

Right and Wrong Images

None Available

Presentations

  1. Zero Energy Ready Home Training
    Author(s): Rashkin
    Organization(s): DOE

Videos

None Available

CAD Images

None Available

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:

  1. 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;
  2. Location does not have significant natural shading (e.g., trees, tall buildings on the south-facing roof, AND
  3. Home as designed has adequate free roof area within +/-45° of true south as noted in the table below.

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. This guide can be accessed on the DOE Zero Energy Home program website at http://www1.eere.energy.gov/buildings/residential/pdfs/rerh_pv_guide.pdf.

2009 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.

2012 IECC

Section R 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.

2009 IRC

Follow the requirements for solar water heating systems found in the 2009 IRC Section M2301 Solar Energy Systems.

2012 IRC

Follow the requirements for solar water heating systems found in the 2009 IRC Section M2301 Thermal Solar Energy Systems.

2009 International Mechanical Code (IMC)

Follow the requirements for solar water heating systems found in the 2009 IMC, Chapter 14, Solar Systems.

2012 International Mechanical Code (IMC)

Follow the requirements for solar water heating systems found in the 2012 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.

Case Studies

  1. Author(s): PNNL, ORNL
    Organization(s): PNNL, ORNL
    Publication Date: December, 2010

    Case study about a 20-unit community of energy-efficient duplexes in Massachusetts that incorporated solar water heating and photovoltaics.

References and Resources*

  1. Author(s): DOE
    Organization(s): DOE
    Publication Date: April, 2017

    Standard requirements for DOE's Zero Energy Ready Home national program certification.

  2. Author(s): Aldrich
    Organization(s): CARB, Steven Winter Associates
    Publication Date: March, 2013
    Brochure on specifications for PV systems.
  3. Author(s): Brooks, Dunlop
    Organization(s): NABCEP
    Publication Date: March, 2012
    This Photovoltaic (PV) Installer Resource Guide is an informational resource covering basic requirements for PV installations intended for individuals pursuing the Photovoltaic Installer Certification credential offered by the North American Board of Certified Energy Practitioners (NABCEP).
  4. Author(s): BSC
    Organization(s): BSC
    Publication Date: June, 2006
    Report aiming to "de-mistify" technology and economic considerations of residential PV systems.
  5. Author(s): EPA
    Organization(s): EPA
    Publication Date: January, 2011

    The RERH specifications and checklists take a builder and a project design team through the steps of assessing a home’s solar resource potential and defining the minimum structural and system components needed to support a solar energy system.

Contributors to this Guide

The following authors and organizations contributed to the content in this Guide.

Last Updated: 06/08/2017

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