Sizing EGC with no overcurrent device

[Bluedog225]

I’m noodling a sketch of my system to prepare for installing my grown up arrays.

I don’t know how to size my equipment grounding conductor from the array to the power shed since there doesn’t seem to be a need for an overcurrent protection device in this part of the system.

Any thoughts on this (or my diagram) appreciated.

Thanks

 

[timselectric]

Size it for the "maximum fuse rating" on the solar panel stickers.
Times 2 , for 2p.

 

[Bluedog225]

I may expand to 4 arrays. Each the same as the two above. That is, each array will have two strings of 7 panels in series and those two strings in parallel.

The fuse rating is 15 amp. if I am reading below correctly. Therefore, for each 7s-2p array 10 awg set of current carrying wires, I’d run an egc rated for 30 amps. That is, another 10 awg wire.

Am I close?

And thanks for helping.

 

[timselectric]

That table is for the current carrying conductors.
Use this for the EGC.




#10 is still correct, for that low of OCP.
Just giving you the correct table.

 

[Bluedog225]

Got it. Thanks

Am I right in thinking that there is no OCP in this circuit?

 

[timselectric]

Got it. Thanks

Am I right in thinking that there is no OCP in this circuit?

Yes
No OCP is required. But it is recommended to have a disconnect near the SCC for service.

 

[Bluedog225]

@timselectric a follow up.

If in ultimately plan 4 arrays needing 15 amps grounding conductor each. So 60 amps.

Two questions:

1. From the Table 250.122 it looks like a 10 awg wire would handle the entire 60 amp grounding conductor requirement. So no need for multiple 10 awg runs. Just the one. Is this right?

2. In the event I add even more arrays, do I need the grounding conductors to be able to handle all arrays simultaneously? Seems like an event that would create the need to safely ground the current would not involve all the arrays at once. Or is that simply the rule and I need to follow it?

Thanks

 

[timselectric]

@timselectric a follow up.

If in ultimately plan 4 arrays needing 15 amps grounding conductor each. So 60 amps.

Two questions:

1. From the Table 250.122 it looks like a 10 awg wire would handle the entire 60 amp grounding conductor requirement. So no need for multiple 10 awg runs. Just the one. Is this right?

2. In the event I add even more arrays, do I need the grounding conductors to be able to handle all arrays simultaneously? Seems like an event that would create the need to safely ground the current would not involve all the arrays at once. Or is that simply the rule and I need to follow it?

Thanks

A single EGC is used for all current carrying conductors ran together. And is sized for the largest circuit in the run or grouping.

 

[timselectric]

If 15a is the largest circuit. A 14 AWG EGC is all that is required to cover all circuits in a single run or grouping. (Like In a conduit)

 

[Bluedog225]

That makes sense. Thanks again Tim.