comments/suggestion are appreciated in here

these are the loads to be powered by the GRID-TIED PV SYSTEM

1 HALLWAY LIGHTS 220 1500 6.82 20
2 HALLWAY LIGHTS 220 1500 6.82 20
3 HALLWAY LIGHTS 220 1500 6.82 20
4 GS AREA LIGHT 220 1500 6.82 20
5 GS AREA LIGHT 220 1500 6.82 20
6 GS AREA LIGHT 220 1500 6.82 20
7 LP PENT-B/6 (GSAL) 220 1500 6.82 20
8 DATA CENTER 220 1500 6.82 20
9 CONVENIENCE OUTLET 220 1260 5.73 20
10 E. DINING LOUNGE 220 1800 8.18 20


IL = 68.47 Amperes
USE : 2-22mm²THHN & 1 - 8.0 mm² in 32mm Ø
Main : 100AT, 150AF, 2P 240V 2-WIRES, 60Hz, 25 KAIC C.B.

these is our calculations on the system

Power Calculation

SUNTECH STP280-24/Vb Xantrex GT3.3 = 3300Wp
Wp: 280 W Total # of Inverters: 5
Voc: 44.8 V
Vmp: 35.2 A
Isc: 8.33 V
Imp: 7.95 A

# of Modules in Series: 10
# of Modules in Parallel: 2
# of Modules in Series: 11
# of Modules in Parallel: 3

Total number of Panels to be used: 53 pieces
Maximun Power @ STC (Pmax): 280 W
Total Power Generated: 14,840 W

Current Calculations

1. Calculating for Maximum Circuit Current

PV Maximum Circuit Current : 10.4125 A
Cable/Conductor and Overcurrent Device Ampacity Rating : 13.015625 A
Overcurrent Device Rating : 15 A


PV Maximum Circuit Current : 52.0625A
Cable/Conductor and Overcurrent Device Ampacity Rating : 65.078125A
Overcurrent Device Rating : 75 A

did i missed something?... and is this correct the connection to the grid we made
I am not that confident about this design, any comments, suggestion regarding this design are appreciated


  • Solar GuppySolar Guppy Solar Expert Posts: 1,980 ✭✭✭
    Re: comments/suggestion are appreciated in here

    Not quite sure what your loads represent ...

    As for the PV side, you should consider using less inverters, my system is about 12kW and I use a pair of Xantrex GT5.0 and one GT3.3

    Your generation will be about 50-70kWhr day depending on the time of year

    Also, on a residential service, having a second breaker panel attached to the meter is not something I have seen before and the electric company and or city/town building department might have something to say about that

    What are you trying to do and what is your location?
  • mike95490mike95490 Solar Expert Posts: 9,464 ✭✭✭✭✭
    Re: comments/suggestion are appreciated in here

    Here is a website that may assist you with load sizing calculations, chose any battery, and calculate the KWH from the final results. What you didn't show clearly, is the amount of time each load will be on.

    Here for battery sizing: (javascript required)
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    gen: ,

  • walang_problemawalang_problema Registered Users Posts: 9
    Re: comments/suggestion are appreciated in here

    good day sir, I live here in Manila Philippines...
    sir regarding the supply side connection i just followed the supply side connection from the articles of code corner MAKING THE UTILITY CONNECTION FOR LARGER SYSTEM by: JOHN WILES
    thank you sir for the advice

    sir sorry for the the drawing I was'nt able to give some of the info, the panel is not the main panel. its a lighting panel for the 3rd floor of the building.

    the meter is a submeter for the 3rd floor who occupies it...

    I am trying to design a GT PV system (no battery backup)... i just maximize the area of the the roof where the array is to be placed. 53 panels can suit the allowable area for the solar panels...

    regarding the loads sir its 17721watts 12 hrs/day all for lightings
    and 2 other convenience outlet...

    thank you sir
    have a productive day
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