Dual multiplus and main panel grounding on offgrid

[cyberwombat]

I know there's been some questions like this before but I wouldn't mind a check. I have an offgrid only system (currently no AC in and 120V single phase only) with dual 24/3000/120V multiplus in parallel. I am working on my main panel wiring (200A Siemens). I've added a jumper between L1/L2 and have a 60A main breaker. My plan is to have a single ground rod connected to a a ground bus bar (PVs are far away but bond to the EMT then the busbar). My understanding is that the Multis bond neutral to ground in inverter mode. I am a bit unsure how to handle my ground in the panel. Is simply having the ground wire from the multis enough or do I need to create a dedicated ground wire going to the ground bus bar?

 

[timselectric]

What you have drawn is correct.

 

[timselectric]

All of your conductors are way oversized.
Which isn't a bad thing, just expensive.
But are not likely to fit in the lugs. So will require pin reducers everywhere.

 

[robbob2112]

You say your PV panels are far away connected to a bus bar that is connected to EMT connected to the inverters without a direct wire doing the job?

Everything I have read so far says don't depend on the EMT for any grounding, run a separage EGC along with the PV wires and use it for ground out there. EMT can corrode or get bad connections and in that case you can loose your ground at the array or have high impeadence which amounts to the same thing.

 

[cyberwombat]

You say your PV panels are far away connected to a bus bar that is connected to EMT connected to the inverters without a direct wire doing the job?

Everything I have read so far says don't depend on the EMT for any grounding, run a separage EGC along with the PV wires and use it for ground out there. EMT can corrode or get bad connections and in that case you can loose your ground at the array or have high impeadence which ammounts to the same thing.

Ah thanks for that. Will explore further

 

[cyberwombat]

What you have drawn is correct.

That makes me so happy . Which conductors do you think will not fit?

 

[timselectric]

You say your PV panels are far away connected to a bus bar that is connected to EMT connected to the inverters without a direct wire doing the job?

Everything I have read so far says don't depend on the EMT for any grounding, run a separage EGC along with the PV wires and use it for ground out there. EMT can corrode or get bad connections and in that case you can loose your ground at the array or have high impeadence which ammounts to the same thing.

Completely agree.
And, I wouldn't use EMT under ground, either.

 

[timselectric]

That makes me so happy . Which conductors do you think will not fit?

All , except for the battery conductors.

 

[Partimewages]

Just an example.
3000 watts @ 120 volts = 25 amps. #10 is good for 30 amps.
6000 watts @ 120 volts = 50 amps #6.

 

[cyberwombat]

Completely agree.
And, I wouldn't use EMT under ground, either.

So PVC pipe for the PV cables? (about 120'). Would you then run a separate ground wire in there as well? I have 6AWG now going to the MPPT. I have EMT there now and also between equipment shed and house/panel (about 20').

 

[timselectric]

So PVC pipe for the PV cables? (about 120'). Would you then run a separate ground wire in there as well? I have 6AWG now going to the MPPT

Yes PVC.
Yes, ground wire.
Sized according to the PV amperage.
In left column.

 

[robbob2112]

Don't forget to pull an extra set of wires in there in case you want to add another array and do lookup the maximum size/number of conductors inside the PVC to get the right size. And think hard about going up one size in wire in case you want to add a few panels to the existing array.
This will save frustration when pulling the wires through by not being to tight and allowing space for the heat. Generally in a buried situation the ground takes care of that.

 

[cyberwombat]

G

Don't forget to pull an extra set of wires in there in case you want to add another array and do lookup the maximum size/number of conductors inside the PVC to get the right size. And think hard about going up one size in wire in case you want to add a few panels to the existing array.
This will save frustration when pulling the wires through by not being to tight and allowing space for the heat. Generally in a buried situation the ground takes care of that.

Good point. Thank you