grounding a small DC/AC system?

Hi Todd,

I just finished up a system similar to yours and had to answer the same question.

According to the IEC, you will use the same protective EARTH ground (ground rods, #2awg) for the entire system.  The purpose of this ground is to conduct large static charges/lightning to the Earth instead of your house.  If you have PV panels or a wind turbines mounted up on a roofline or a tower, they should have grounding rods too, preferably close to the base of the mounts - not routed back to the house!

That said, the AC neutral, which is usually tied to Earth ground at the breaker panel/disconnect, should never be tied to the DC ground.  Doing so could create a safety hazard and/or damage your gear.

Also since you have two inverters, you need to have those tied into a single disconnect so that all AC power is disconnected from loads with the flip of a single lever.  The disconnect needs to be located where the fire department can easily get to it in the event of a fire.

For my system (1200W PV/Wind, 2500W AC + DC lighting), I have an AC and two DC disconnects for each source mounted on the outside of my power shed.  Each should be clearly marked.

Maybe more than you asked, but I hope this helps.

-Gregg

Todd
Is there any other ac source in your building, or is the only ac from your inverter ?