Siemens solar-ready panels and Simovert inverters: what the sources show
Two meanings of “Siemens solar” besides panels: electrical panels with a place for a solar breaker, and the Simovert pump inverters in a Sahel water programme.
Key takeaways
- A solar-ready panel is an electrical panel with provisions for a solar breaker; it is not a solar panel.
- The simple 120 % rule on a 200 A bus with a 200 A main allows a 40 A backfed breaker; the full rule in NEC 705.12 also limits inverter current.
- The Sahel note shows 3.5 kVA Simovert-P-Solar inverters driving Grundfos and KSB pumps directly from the array.
Searches for ‘Siemens solar’ often mean something other than a module. Two of those meanings can be explained from solid sources, and we limit this page to them.
Solar-ready electrical panels
A solar-ready load centre or meter-main is an electrical panel with provisions for a solar breaker. It is not a solar panel. In the US, section 705.12 of the National Electrical Code (the ‘120 % rule’) allows a backfed solar or battery breaker on a busbar when 125 % of the inverter’s output current plus the main overcurrent device does not exceed 120 % of the busbar rating, and the backfed breaker must sit at the opposite end of the bus from the main. The simple version of the rule gives the commonly quoted figures below, which assume the inverter’s 125 % current fits the allowance.
| Bus rating | Main breaker | Largest backfed breaker (simple form) |
|---|---|---|
| 100 A | 100 A | 20 A |
| 125 A | 125 A | 25 A |
| 200 A | 200 A | 40 A |
| 225 A | 200 A | 70 A |
| 225 A | 225 A | 45 A |
The code edition adopted differs by jurisdiction, and alternatives such as a supply-side connection or a main-breaker derate exist. Leave the design to a licensed electrician.
Simovert-P-Solar inverters
The Sahel programme note lists 3.5 kVA Simovert-P-Solar inverters driving Grundfos and KSB centrifugal pumps from Siemens M50 modules (see the gas and water case files). It is the clearest example in Siemens’ documentation of a Siemens-branded solar inverter: a pump-drive inverter fed directly from the array.
What this page does not cover
Siemens also sold other PV-related products over the years, including grid inverters and, in Europe, home battery storage, and it has been a shareholder in the storage company Fluence. We do not have primary sources for them here and do not describe them; for those, go to Siemens’ and the products’ current manufacturers’ documentation.
Questions readers ask
Is a Siemens solar-ready panel the same as a solar panel?
No. It is an electrical service panel or load centre with a provision for a backfed solar breaker.
Does the 120 % rule apply to batteries too?
Yes. A backfed breaker for a solar inverter or a battery inverter falls under the same busbar-loading rule in the US code.
Can I exceed the simple-form breaker size?
Sometimes, by derating the main breaker or connecting on the supply side, but those are design decisions for a licensed electrician under the code edition in force.
Does Siemens still sell solar modules?
The modules on this site are legacy products. For current Siemens products, use Siemens’ own documentation.
Related guides
Wiring Siemens solar modules: series, parallel and bypass diodes
Wiring rules from the Siemens datasheets: maximum system voltage by model, series and parallel strings, cold-weather Voc, 6 V versions and bypass diodes.
Read more →Siemens Solar for gas wells and water pumping: installations
Siemens Solar installations for gas-well telemetry in Texas, 330 water pumping stations in the Sahel and Amazon drinking water, with component lists.
Read more →Typical Siemens solar system diagrams
Block diagrams of four PV system types from Siemens Solar’s original system page: directly connected, stand-alone, generator hybrid and grid-interactive.
Read more →Read the installation notes behind the Simovert pump systems.