Mike Dolt Enterprises
Mike Dolt Enterprises
User: Whitman Solar
Asked on: Thursday, March 24, 2011 at 12:33 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:13 am EDT
Question: We design commercial PV systems and for the most part central inverter types. We have done a few string inverter designs and have a question about Equipment Grounding Conductors.If we have a roof top array consisting of a DPW rack system all connected together and it is serving as a grounding electrode by using WEEB clips, and we have 3 string inverters for that array, how many equipment grounding conductors should be run? Should there be one for each inverter, and how does the DPW rack effect the size of the conductor? Do we need to separate the rack for each inverter?Thanks
Number of Equipment Grounding Conductors (EGCs)
Based on the provided information, you should run one EGC for each string inverter.
DPW Rack System
The DPW rack system, when properly connected, can serve as a grounding electrode. The WEEB clips create a continuous grounding path between the rack components, which is connected to the grounding system at the main electrical service panel.
EGC Size
The size of the EGC is determined by the maximum current that can flow through it. In this case, it is the maximum short-circuit current that could flow through the inverter. The table below provides the minimum EGC sizes based on the maximum short-circuit current:| Maximum Short-Circuit Current | Minimum EGC Size
| ---|--- |
| Over 30A to 60A | 6 AWG |
| Over 100A to 200A | 2 AWG |