Two Grounding question

[walaby]

So I know that inside the structure (house), high voltage DC PV wires need to be in metal conduit.

My original plan was PVC external transition to EMT in the house, to an IMO disconnect (which has non-metallic box) and I was planning on a separate ground from a metal EMT junction box, pass through the IMO box and connect to the ground bus bar in the inverter. Now, further research indicates that the IMO disconnect needs to be in a metal box if it is mounted inside the structure. That said, I also believe the IMO disconnect is redundant to the built in PV switch on the inverter.

First question. If I eliminate the IMO disconnect inside the house, if I run EMT to the inverter, the inverter is plastic/PVC case. Do I still need to run a separate ground to properly ground the raceway/conduit since the inverter is not in a metal case? And if so, can I run from ground screw in junction box, through conduit, and connect to ground bus bar in inverter?

Second - I am planning on ground all panels together with grounding lugs and running the ground through the PVC (outside) and then through the EMT (inside structure). Can that panel ground be connected to the ground bus bar in the inverter? There is ground connection from inverter, through AC circuit breaker, through a manual transfer switch, to the main panel ground. Or does this panel ground HAVE to go directly to the main service panel ground?

Hope this makes sense.

Thanks in advance for the help

Mike

 

[sumpower]

First question, yes you need to run a ground wire with any current carrying conductors.

If you want to use the ISO switch, you can bond the ground through the use of a bushing threaded to the EMT conduit entering and leaving the plastic housing of the switch.

https://www.platt.com/p/0169854/3-4-insulated-grounding-bushing-lay-in-lug/018997004512/34dcigbu

Question #2, ground wire at the inverter is fine, as long as there is a path (conductor/green wire) to the ground bar in the main panel.

 

[walaby]

Thanks sumpower. So for Q1, if I run separate ground from junction box, through EMT and connect to inverter ground bus that would adequately ground the EMT correct? Or should I use ground bushing at physical connection in the plastic inverter case? Or is either way acceptable?

If I choose to use the IMO box and use the bushings is the ground uninterrupted through both bushings and then continue uninterrupted, terminating at inverter ground bus bar? Think I read somewhere that it is uninterrupted but I’ve read so much lately, I could be punch drunk

Thanks for the quick response

Mike

 

[sumpower]

Use the lay-in lugs on the grounding bushings to bond the ends of the EMT to the ground wire. That way the EMT maintains a bond that has the shortest path to ground.

The ground path is uninterrupted when connecting the ground wire to the grounding bushings. This keeps the ground wire and the EMT at the same ground potential. Yes, terminate the ground wire on the ground bus at the inverter. Just be sure to have a ground wire on the inverter ground bus that is run to the ground bar at the first panel.

 

[walaby]

Thank you sir!!!!

Appreciate it.

Mike