grid tie and hybrid connected

boatlagoon

I have a 3.5kw array connected to a hybrid inverter and no more roof room on the house. Everything works well so far.

I have a garage 25 metres away where I can put more panels but have no way of running a large cable between house and garage but I do have a 2.5mm existing cable (under concrete) as a power feed to said garage.

Can I connect a grid tie inverter in garage to house ie. hybrid through existing cable?

BB.

Could you setup a system "physically"? Yes...

HOWEVER, this will depend on your local building/electrical codes... I have no knowledge of UK codes.. But it appears that 2.5mm cable is rated for around 20 to 27 amps.

The maximum GT Solar inverter you could install would be (again, just guessing to get some approximate numbers):

• 20 amps * 230 volts = 4,600 Watts
• 27 amps * 230 volts = 6,200 Watts

So, anything less than 4,600 Watt GT inverter would seem to be functional for your needs.

The next issue is that you are mixing GT Solar feeds... You have one array that feeds your main breaker panel (the existing 3.5 kWatt system), and you would have a second combined Garage Loads + Solar feed. 

Many codes treat solar power feeds "differently" than normal circuits... The fact that would have two separate solar feeds to the main breaker panel--First you need to see if your code allows for more GT Solar (and your local code, your utility, etc.). I.e., if you add another 3.5 kWatt for the garage, you now have 7.0 kWatt of GT solar feeding the main panel ("legal"?). Your utility may require an "engineering review" of your neighborhood distribution system to make sure that your new GT solar does not "overload" the the local utility system.

The second is that many codes require separate GT Solar disconnects to allow the utility to shutdown your GT solar while linemen are working on the utility poles/transformers/etc. In many regions, this is no longer a requirement (acceptance by utilities that GT Solar inverters do not create any hazards for utility workers). Having two solar disconnects in different locations (i.e., one on home a second in garage)... Or two disconnects at home panel (one to disconnect home GT solar, and a second disconnect that "kills power" to your garage (i.e., also kills power to garage solar and any garage loads such as a freezer may not be ideal for you--But the disconnects will probably never to turned on by your utility in "real life").

Off hand, I think a properly designed GT solar garage installation would function well and safely--But you may have issues with local building codes and approvals that need to researched (ask questions of local building code folks, etc.).

-Bill