While it can appear a little daunting at first, a PV system can be broken down into easily understood building blocks as follows:
1) Several PV modules are strung together
2) whose output is accumulated in a combiner box
3) whose output is sent through a DC disconnection switch
4) which is then fed to an AC inverter (that converts the DC to house/grid compatible AC)
5) that is then fed to your house service box (which is already connected to the grid)
Typically, all of these building blocks have UL and NEC compliance and use UL and NEC compliant cables and connectors to bring it all together. Not so complicated, right?