I was just wondering if it's still the case that solar panel installations are rated to 16 amps single phase does this apply to all single phase generators on domestic installations
Hello Kelly, just to be clear, the inverter is rated to 16 amps, but you can have up to 5.7kW of modules (panels) on some inverters, this gives you an oversizing of 155%.
Do such ratings limitations only apply to those installations intended for connection to the grid? What about a stand-alone building which is completely off-grid?
There is no limit on the capacity of a stand alone PV array. I know of one that is 20 Kw.
The 16 amps per phase is the standard limit for domestic and similar grid tied PV arrays. Much larger grid tied arrays are possible but the permission and approval process is much more complex.
There are grid tied solar farms with outputs of hundreds of kw, and AFAIK nothing prohibits anyone from building one, subject to obtaining all required permits and approvals. A dedicated substation would probably be required, and maybe reinforcement of the distribution network.
Off grid you can do what you like in terms of power, voltage, frequency (24 V DC anyone?) etc. You are as they say on your own. But if any part is to be connected to grid in a way that exports then all the requirements to be on frequency, on voltage and meet auto-shutoff times etc applies. And the power limit, so basically an approved inverter unit under 16A /phase or a lot of paperwork and testing.
There are no limits for off grid installations. Just need to engineer them soundly.
You can go over 16A/phase on grid but you need to comply with the new codes which can be expensive. In any case your local DNO can refuse any export if the system isnt suitable (e.g. because of existing generation). You do need to check.
The economics are most favourable when you displace import. Once you export the value of a kWh will drop by around 75% as you dont get credit for all the non energy charges.
