Do you need a disconnect at a ground-mounted array?

Is there any code requirement that states you need a PV disconnect at the location of a ground mount? Or can the disconnect be remote next to the inverters and a plaque showing where it is at the ground mount?
 

ggunn

PE (Electrical), NABCEP certified
Is there any code requirement that states you need a PV disconnect at the location of a ground mount? Or can the disconnect be remote next to the inverters and a plaque showing where it is at the ground mount?
If the inverters are remote from the array, then no, I don't think you have to have a disco at the array, though it might be a good idea. You don't need a placard, either; that's for AC sources.
 

tortuga

Senior Member
The outside feeder is covered under 225 (however a disco is not required at the supply end).
A DC disconnect is required where it first enters the structure it supplies 225.32.
I personally would put one on the pole, but don't see anything other than 690.13(A) requiring you to put one there.
 

ggunn

PE (Electrical), NABCEP certified
The outside feeder is covered under 225 (however a disco is not required at the supply end).
A DC disconnect is required where it first enters the structure it supplies 225.32.
Most inverters have integrated DC disconnects, so they have that covered, if it's even required in this case. If the inverters are on an outside wall, the DC never enters the building.
I personally would put one on the pole, but don't see anything other than 690.13(A) requiring you to put one there.
So would I.
 

electrofelon

Senior Member
The outside feeder is covered under 225 (however a disco is not required at the supply end).
A DC disconnect is required where it first enters the structure it supplies 225.32.
I personally would put one on the pole, but don't see anything other than 690.13(A) requiring you to put one there.
If AC were run out to the ground mount, I would say per 225 we might need a disconnect. I say might because of the revised definition of "structure" and "equipment" is now not a structure. It's a bit gray to me. Its really just academic tho as most inverters have AC disconnects, and a combiner panel will usually have less than 6 throws if MLO.

Just for completeness, one thing I have done is use 230.40 exception 3 to serve a ground mount. In that case of course there needs to be service disconnect.
 

ggunn

PE (Electrical), NABCEP certified
If AC were run out to the ground mount, I would say per 225 we might need a disconnect. I say might because of the revised definition of "structure" and "equipment" is now not a structure. It's a bit gray to me. Its really just academic tho as most inverters have AC disconnects, and a combiner panel will usually have less than 6 throws if MLO.
The six handle rule does not apply to a combiner, AC or DC, MLO or no, as long as it doesn't connect directly to the service conductors with no disco between it and them.
 

electrofelon

Senior Member
The six handle rule does not apply to a combiner, AC or DC, MLO or no, as long as it doesn't connect directly to the service conductors with no disco between it and them.
Hmmm, well the 6 handle rule doesn't apply to the article 690 disconnects, but would apply to any article 225 or 230 requirements. Do you concur with that statement? Is there a way to NOT classify the AC conductors going to a combiner panelboard at a ground mount as a article 225 feeder?
 

jaggedben

Senior Member
If we are talking DC, I think it's doubtful we have any 'feeders'. 690 defines DC circuits in ways that exclude all parts of other circuits that are definitely feeders, and Chapter 6 takes precedence over Chapter 2.

If we are talking AC, it's a little more complicated, as there is no way to make sense of the definition of inverter output circuits without acknowledging that parts of it can also be service conductors or feeders at the same time. It would be hard to argue against an AHJ who wants to enforce 225, especially since 225.32 contains two article-specific exceptions that aren't for 690.
 

ggunn

PE (Electrical), NABCEP certified
Hmmm, well the 6 handle rule doesn't apply to the article 690 disconnects, but would apply to any article 225 or 230 requirements. Do you concur with that statement? Is there a way to NOT classify the AC conductors going to a combiner panelboard at a ground mount as a article 225 feeder?
If an MLO AC combiner is connected directly to service conductors, then the number of handles is of course governed by the six handle rule, but if there is a disco between it and the service conductors, then there is only one handle. I have PV systems in place with 30 or more inverters (one has 42) feeding MLO AC combiners in line side interconnections, but they all have a disco between the combiner and the service, so there is only one handle.
 

electrofelon

Senior Member
If we are talking DC, I think it's doubtful we have any 'feeders'. 690 defines DC circuits in ways that exclude all parts of other circuits that are definitely feeders, and Chapter 6 takes precedence over Chapter 2.

If we are talking AC, it's a little more complicated, as there is no way to make sense of the definition of inverter output circuits without acknowledging that parts of it can also be service conductors or feeders at the same time. It would be hard to argue against an AHJ who wants to enforce 225, especially since 225.32 contains two article-specific exceptions that aren't for 690.
I agree. Similarly, as I have complained in the past, it's also not always possible to differentiate between a supply side connection and a load side to a 230.40 exception 2 install
 
2017 NEC 690.15: Isolating devices shall be provided to isolate PV modules, etc. from all conductors that are not solidly grounded. This would require an isolating device at the array. Isolating device is defined as something like a disconnect, but not requiring an interrupting rating.
 

ggunn

PE (Electrical), NABCEP certified
2017 NEC 690.15: Isolating devices shall be provided to isolate PV modules, etc. from all conductors that are not solidly grounded. This would require an isolating device at the array. Isolating device is defined as something like a disconnect, but not requiring an interrupting rating.
I'm pretty sure that MC4 connectors are considered a disconnecting means for this purpose.
 

sketchy

Senior Member
We are required on AC or DC to have a disco on a separate structure, which a ground mount is considered to be.
 

tortuga

Senior Member
If we are talking DC, I think it's doubtful we have any 'feeders'. 690 defines DC circuits in ways that exclude all parts of other circuits that are definitely feeders,
I just had to revisit this question for I project I am working on and I'll add to this.
I still think article 225 applies but since the feeder is 'leaving' the pole I no longer think 225.31 applies :) in this case.

A pole mount PV array is a Separately Derived System that supplies a feeder to another structure 690 does not modify that.
Explanation:
Per 90.3 article 690 can subtract a specific requirement of article 225 but it must do so explicitly, which it does not do.
For example recently the 2017 NEC deleted the redundant 690.3 requirement based on "proper use of code structure per 90.3".

Code:
2014 NEC 690.3 Other Articles
Wherever the requirements of other articles of this Code and
Article 690 differ, the requirements of Article 690 shall apply
and, if the system is operated in parallel with a primary source(s)
of electricity, the requirements in 705.14, 705.16, 705.32, and
705.143 shall apply.
Article 225.1 Scope states
Code:
This article covers requirements for outside branch circuits and feeders run on or between buildings, structures, or poles on the premises.."
Table 225.3 goes on to mention article 690.

690 does define the Photovoltaic Output Circuit:
Code:
Circuit conductors between the PV source circuit(s) and the inverter or dc utilization equipment.
We have a pole mounted array and we need to run a Photovoltaic Output Circuit from the pole(s) to the inverter or dc utilization equipment.
Per the definition that is both a feeder and a 'Photovoltaic Output Circuit'.

For example there are other cases where something can meet more than one code definition a common recessed can light meets the definition of luminaire and that of an outlet.

We are required on AC or DC to have a disco on a separate structure, which a ground mount is considered to be.
sketchy: can you find out from the AHJ what specific code section they are talking about? I am curious if it really is a local code or an interpretation of 225.31.
 

electrofelon

Senior Member
I would say a PV system is NOT an SDS, particularly with transformerless inverters. The concept of an SDS never really was applied to PV systems.
 
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