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Home My WebLink AboutLA208905 - APPROVED - PE Stamped Plan Set 76 North Meadowbrook Drive Scott E. Wyssling, PE Alpine, UT 84004 Coleman D. Larsen, SE, PE office (201) 874-3483 Gregory T. Elvestad, PE swyssling@wysslingconsulting.com December 15, 2022 Current Insight 2852 W. Amini Way South Jordan, UT 84095 Re: Engineering Services Englund Residence 9464 183rd Court, Lakeville, MN 15.200 kW System To Whom It May Concern: We have received information regarding solar panel installation on the roof of the above referenced structure. Our evaluation of the structure is to verify the existing capacity of the roof system and its ability to support the additional loads imposed by the proposed solar system. A. Site Assessment Information 1. Site visit documentation identifying attic information including size and spacing of framing for the existing roof structure. 2. Design drawings of the proposed system including a site plan, roof plan and connection details for the solar panels. This information will be utilized for approval and construction of the proposed system. B. Description of Structure: Roof Framing: Prefabricated wood trusses at 24” on center. All truss members are constructed of 2x4 dimensional lumber. Roof Material: Composite Asphalt Shingles Roof Slope: 37 degrees Attic Access: Accessible Foundation: Permanent C. Loading Criteria Used • Dead Load o Existing Roofing and framing = 7 psf o New Solar Panels and Racking = 3 psf o TOTAL = 10 PSF • Dead Load o Existing Roofing and framing = 7 psf o New Solar Panels and Racking = 3 psf o TOTAL = 10 psf • Live Load = 20 psf (reducible) – 0 psf at locations of solar panels • Ground Snow Load = 50 psf • Wind Load based on ASCE 7-16 o Ultimate Wind Speed = 115 mph (based on Risk Category II) o Exposure Category C Analysis performed of the existing roof structure utilizing the above loading criteria is in accordance with the 2020 Minnesota State Building Code (2018 IRC), including provisions allowing existing structures to not require strengthening if the new loads do not exceed existing design loads by 105% for gravity elements and 110% for seismic elements. This analysis indicates that the existing framing will support the additional panel loading without damage, if installed correctly. Page 2 of 2 D. Solar Panel Anchorage 1. The solar panels shall be mounted in accordance with the most recent Ironridge installation manual. If during solar panel installation, the roof framing members appear unstable or deflect non-uniformly, our office should be notified before proceeding with the installation. 2. The maximum allowable withdrawal force for a 5/16” lag screw is 235 lbs per inch of penetration as identified in the National Design Standards (NDS) of timber construction specifications. Based on a minimum penetration depth of 2½”, the allowable capacity per connection is greater than the design withdrawal force (demand). Considering the variable factors for the existing roof framing and installation tolerances, the connection using one 5/16” diameter lag screw with a minimum of 2½” embedment will be adequate and will include a sufficient factor of safety. 3. Considering the wind speed, roof slopes, size and spacing of framing members, and condition of the roof, the panel supports shall be placed no greater than 48” on centers. 4. Panel supports connections shall be staggered to distribute load to adjacent framing members. Based on the above evaluation, this office certifies that with the racking and mounting specified, the existing roof system will adequately support the additional loading imposed by the solar system. This evaluation is in conformance with the 2020 Minnesota State Building Code (2018 IRC), current industry standards, and is based on information supplied to us at the time of this report. Should you have any questions regarding the above or if you require further information do not hesitate to contact me. Very truly yours, Scott E. Wyssling, PE Minnesota License No. 57927 Concept Approval ONLYSubject to Field Inspection Inspector Date 2020 MN Bldg Code 12/16/2022dpfannenstein Please provide a copy of the City Approved plans on site at final inspection. Signed 12/15/2022 For each roof plane with a photo-voltaic array, two pathways not less than 36" wide shall be provided from the lowest roof edge to ridge on the same roof plane as the array,on an adjacent roof plane, or straddling the same and adjacent roof planes. Not fewer than one pathway shall be provided on the street or driveway side of the house. Concept Approval ONLYSubject to Field Inspection Inspector Date 2020 MN Bldg Code 12/16/2022dpfannenstein Not less than an 18" clear setback is required on both sides of a horizontal ridge. AC WIRE CALCULATIONS - MATERIAL: COPPER & TEMPURATURE RATING: 90°C REQUIRED CONDUCTOR AMPACITY: INVERTER OUTPUT CURRENT X = OF INVERTER'S MAX CURRENT PER 690.8(A)(3) X 125% PER 690.8(2)(A) CORRECTED AMPACITY CALCULATIONS: AMPACITY X TEMPURATURE DERATE FACTOR X CONDUIT FILL DERATE = DERATED CONDUCTOR AMPACITY DERATED CONDUCTOR AMPACITY CHECK: MAX CURRENT PER 690.8(B)(2)(2) < DERATED CONDUCTOR AMPACITY CONDUIT SCHEDULE SINGLE LINE DIAGRAM PV-3 PROJECTSUMMARY REVISIONSELECTRICAL CALCULATIONS TAG ID 1 2 3 REQUIRED CONDUCTOR AMPACITY CORRECTED AMPACITY CALCULATION CERATED CONDUCTOR AMPACITY CHECK AC WIRE SIZING CALCULATIONS BASED OFF FOLLOWING EQUATIONS >> x 15 30=x15.00 0.871.25 15.00 0.871.25 48 0.871.25 x x <= = = 1 26.10A 26.10A18.75A 34.80A 34.80A18.75A 65.25A 65.25A60A = = = 18.75A 1 x 15 40=xx x <118.75A 48 x 1 75=xx x <160A TAG ID 1 2 3 CONDUIT SIZE CONDUCTOR NEUTRAL GROUND NONE (2) #10 AWG PV WIRE PERBRANCH CIRCUIT NONE (1) #6 BARE COPPER WIRE (6) 10 AWG THHN/THWN-2 NONE (1) 10AWG THHN/THWN-2 (2) 6 AWG THHN/THWN-2 (1) 8 AWG THHN/THWN-2 (1) 10AWG THHN/THWN-2 MIN 3/4''EMT OR EQUIV MIN 3/4''EMT OR EQUIV GRID-TIED SOLAR POWER SYSTEMErik Englund 9464 183rd Court, LakevilleMN, 55044 1 CASE # 6830 INSTALLER: CENTAURI SYSTEMS LLC PHONE: 763-229-9046 3922 VAN BUREN ST NE MINNEAPOLIS, MN 55421 NOTES 1. the design shall meet National Electric Code (NEC codes) requirements 2. ALL TESTING SHALL BE PERFORMED BY QUALIFIED PERSONNEL, WITH PROPER PERSONAL PROTECTIVE EQUIPMENT 3. AC DISCONNECT SHOULD BE LOCATED IN A READILY ACCESSIBLE LOCATION WITHIN 10' OF THE MAIN SERVICE METER 4. 24/7 UNESCORTED KEYLESS ACCESS SHALL BE PROVIDED FOR THE METERS AND AC DISCONNECT 6. Inverter and Modules conform to and are listed under UL 1703 7. Conductors exposed to sunlight and wet locations shall suitable and listed per NEC article 300.6(C)(1) and 310.10(C) 8. Non splicing lugs will be used Site details Racking configuration Iron ridge rx 100 rails, flashfoot 2 attachment points PV System (38) 400 watt modules total (15.2 KW dc total) Inverter Details Enphase IQ8A microinverters aggregate kW AC nameplate rating of system: 13.262 kw individual kW AC nameplate rating of each inverter: 349 VA AC Voltage of the DER System: 240v number of phases of the inverters: 1 PHASE Number of phases of the DER system: 1 PHASE PV-4 PROJECTSUMMARY REVISIONS