| 1831 | Australia | Ocon Services Pty Ltd | Lakes Business Park, 2B Lord Street, Botany NSW 2019 | +61 1300 626644 | www.ocon-services.com.au | | |
| 1832 | Australia | Off Grid Solar Kits | | +61 1300 883847 | www.offgridsolarkits.com.au | SMA Solar Technology AG, Selectronic Australia Pty Ltd, Schneider Electric SA | |
| 1833 | Australia | Off The Grid Electrical | | +61 409 285911 | www.offthegridelectrical.com.au | | |
| 1834 | Australia | Off-Grid Electrician | Sydney, NSW | +61 1300 361102 | offgridelectrician.com.au | | |
| 1835 | Australia | Off-Grid Energy Australia | 3/62 Pym St, Dudley Park, SA 5008 | +61 1300 334839 | www.offgridenergy.com.au | | |
| 1836 | Australia | Ogden Power | 1 Stokes St in Alice Springs | +61 8 89534211 | ogdenpower.com.au | | Win Win Precision Technology Co., Ltd. |
| 1837 | Australia | OHM Electrical Services Pty Ltd (QLD) | 33 Murcot St., Brisbane, QLD 4119 | +61 422 949107 | www.ohmelectrical.com.au | | Hanwha Q CELLS GmbH, Trina Solar Limited, Jinko Solar Holding Co., Ltd. |
| 1838 | Australia | Olympic Solar | PO Box 444, Prospect SA 5082 | +61 8 83445414 | www.olympicsolar.com.au | | |
| 1839 | Australia | Omega Solar and Batteries | 5A Appaloosa Court, Mudgeeraba 4231 | +61 1300 663422 | https://omegasolarandbatteries.com.au | LG Electronics, Inc. | |
| 1840 | Australia | OmniSolar Services | PO Box 6, Buderim, QLD, 4556 | | omnisolar.com.au/ | | |
| 1841 | Australia | Ondemand Data & Electrical | Newport, Melbourne, VIC | +61 433 700111 | https://www.ondemandelec.com.au | | |
| 1842 | Australia | One Earth Electrics | Saint Georges Terrace, Perth, WA 6000 | +61 417 782019 | https://www.oneearthelectrics.com | Yaskawa - Solectria Solar, SMA Solar Technology AG, Fronius International GmbH, ReneSola Ltd., Enphase Energy, Inc. | |
| 1843 | Australia | One Eco | 4/23 Essington Street Mitchell ACT 2911 | +61 413 582506 | www.oneeco.com.au | | |
| 1844 | Australia | One Flash Electrical | Tamworth, NSW | +61 411 537301 | www.oneflashelectrical.com.au | | |
| 1845 | Australia | One Point Electrical and Communications | Burrum Heads, 38, Louise Drive, 4659 | +61 43 5950723 | onepointec.com.au | | |
| 1846 | Australia | One Power Solar & Electrical | 4/17 Oak Ave Miami, QLD 4220 | +61 1300 568589 | onepower.com.au | | |
| 1847 | Australia | One Source Contractors | 9/43 Station Avenue, Darra, QLD, 4076 | +61 1300 103215 | https://onesourcecontractors.com.au | | |
| 1848 | Australia | One Stop Solar | PO Box 2, Buddina, QLD 4575 | +61 1300 206951 | https://onestopsolar.com.au | SMA Solar Technology AG, SolarEdge Technologies, Ltd., Fimer S.p.A., SolaX Power Network Technology(Zhejiang) Co.,Ltd. | |
| 1849 | Australia | Onshore Electrical Solutions | 50 East Ter, Kensington Gardens, SA, 5068 | +61 488 068779 | https://onshoreelectricalsolutions.com.au | | |
| 1850 | Australia | Onsite Electrical Pty Ltd | | +61 412 871622 | www.onsiteelectrical.com.au | | |
| 1851 | Australia | OnSolar | 204 Clarence Street, Sydney, NSW 2000 | +61 1300 889175 | https://onsolar.com.au | SMA Solar Technology AG, Sungrow Power Supply Co., Ltd. | |
| 1852 | Australia | Open Electrical | PO Box 107, Mount Gravatt 4122 | +61 423 197484 | www.openelec.com.au | Trina Solar Limited | SMA Solar Technology AG, KACO New Energy GmbH, Enphase Energy, Inc., ABB Italy S.p.A., Schneider Electric SA |
| 1853 | Australia | OPT Energy | 9/9 Woolboard Road, Port Melbourne, VIC 3207 | +61 3 96060987 | optenergy.com.au | SMA Solar Technology AG, Fronius International GmbH, SolaX Power Network Technology(Zhejiang) Co.,Ltd. | |
| 1854 | Australia | Optimal Power Solutions Pty Ltd | 1/95 Hope Street, Brunswick, VIC, 3056 | +61 770 58649862 | www.optimal-power-solutions.com | | |
| 1855 | Australia | Optimus Energy | 26 Humphries Tce, Kilkenny SA 5009 | +61 1300 881118 | www.optimusenergy.com.au | SMA Solar Technology AG, Fronius International GmbH, Enphase Energy, Inc., AISWEI New Energy Technology (Jiangsu) Co., Ltd. | Xiamen Hopergy Photovoltaic Technology Co., Ltd |
| 1856 | Australia | Orana Energy Systems Pty Ltd | 100a, Talbragar Street, Dubbo, NSW, 2830 | +61 2 68852295 | www.oranaenergysystems.com | | |
| 1857 | Australia | Origin Energy Ltd. | | +61 3 86353485 | www.originenergy.com.au | | |
| 1858 | Australia | Orion Electrical & Lighting Design | P.O. Box 234, Craigieburn VIC 3064 | +61 1300 295803 | https://www.orionelectricalandlightingdesi... | | |
| 1859 | Australia | OSE Electrical | | +61 421 376206 | https://www.oseelectricalservices.com | | |
| 1860 | Australia | Oslec Electrical | 91, Research Road, Pooraka, SA, 5095 | +61 1300 495045 | oslec.com.au/ | SMA Solar Technology AG, Fronius International GmbH, AISWEI New Energy Technology (Jiangsu) Co., Ltd., GoodWe Power Supply Technology Co., Ltd. | |