Sunday, September 21, 2014
The SolarEdge system is nice in that the microinverters (SolarEdge calls them "optimizers") only output 1 volt each when the inverter is shut down. I'm not saying you wouldn't get a nice shock if you put your tongue on the wires, but it's not going to kill you. So it's nice and safe to work around.
Today, we worked on getting all the array wiring hooked up. Each panel gets an optimizer installed on it. You can mount them on the racking, but we chose to mount them in one of the pre-drilled holes on the panels. Since we have 32 panels, we had to mount 32 optimizers.
Each optimizer has 4 wires coming out of it: the 2 short wires receive the wires from the panel to which the optimizer is attached (one positive and one negative). The longer wires are used to connect the optimizers together in a "string". Our design called for 2 strings of 16 panels each, where String 1 will connect in to Inverter 1 and String 2 goes to Inverter 2. Starting with the first panel, you connect the negative wire from optimizer 1 to the positive wire on the second optimizer. Rinse and repeat until they are all tied together. These wires use MC4 connectors, which are the standard for solar installations. They just click together and it's failsafe, since one end is a male end and other female. There's no way, really, to connect the wrong wires together.
Since we know that each optimizer outputs 1 volt, then we can easily use a voltmeter to test each string of panels to make sure everything is working properly. With 16 panels, we should get 16 volts. Looks like it's working!
We used special clips called SunRunner clips to organize the wiring under the panels and make it nice and neat. If you click and biggify the picture aove, you can see some of these clips to the right of the voltmeter as well as the MC4 connectors.
Finally, we needed to drive the ground rod and then run the ground wire across the front of the panel. There's a special connector on each support that holds the ground wire tight as it runs across the array. Using a neighbor's Hilti, we drove the rod down in the ground and then connected the solid copper ground wire to the rod with an acorn clamp. From there, stranded copper ran from the ground and into a junction box where it will then go into the conduit and into the house.
We just have to finish up that junction box wiring and then we're pretty much ready for the city to inspect everything. I'll show you that tomorrow.