PV disconnect confusion

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generatorlabs

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This will be my first PV install.
I am performing the install at my own location to get some practical experience.
Gathering a list of items I will need to get the groundwork in place.

The install is straight forward. 16 Panel array with micro-inverters on each panel.
The micro-inverters are intelligent and use weather rated, summing cables to string all the units to a final junction box on the roof.
I will bring the final junction down the side of the house within PVC conduit as shown here:

Side.jpg
Here is my dilemma. The 200 Amp master breaker is on the opposite side of the house from the load center that it feeds. The feed to the load center is probably 50+ feet in length. The load center has room for extra breakers.

pt3.jpg 2016-10-07 21_22_18-Settings.jpg

The utility demands that the main home disconnect and the PV disconnect be close to each other.
However I must back-feed the PV into the system via a double pole breaker.
This is problematic because I do not have easy access to the load center from the meter side of the house.
It would also mean that the PV run would exceed 100' which seems inefficient.
Is there a way that I can put a small sub-panel next to the main breaker that will meet code?
If a sub panel is possible how does one tap the main breaker panel in way that meets code?

Thanks for any insight!
 
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You can use Polaris tap lugs and tap conductors between meter and main breaker.
Disconnect needs to be right next to tap with 10ft

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Also the utility can't tell you that you can't install your solar back feed breaker a mile away and 100ft distance is not bad you can do a voltage drop calculation but it should be fine.

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zman990 said:
You can use Polaris tap lugs and tap conductors between meter and main breaker.
Disconnect needs to be right next to tap with 10ft
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Thank you zman990....that is exactly the response I needed to hear.
The engineer who provided the original plans specifies a supply side tap but does not go into the specifics on how to accomplish this while remaining code compliant.
Experience has taught me that double tapping at a lug is never a good idea and that type of work shall not occur on my watch.
Since the idea of back-feeding a second line of service to a main breaker is new to me I really needed to see some best practices and code compliant measures to accomplish this.
A quick Google of the Polaris tap lugs shows a clean method.

zman have you used the Polaris line-up in the past? Are there any quirky conditions that inspectors look for when these items are utilized? (ie distance from breaker, distance from a loop, distance from each other)

Thanks for the info!
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zman990 said:
Also the utility can't tell you that you can't install your solar back feed breaker a mile away and 100ft distance is not bad you can do a voltage drop calculation but it should be fine.

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I agree. I am trying to prevent the necessity of making holes in sheetrock to gain a path for an interior cable run to the load center. The floorplan does not offer an easy way to get across the house.
In fact I would have to run it twice because I am running two arrays with room for adding more in the future.

So I could go with:
a) 2 power runs, 2 double pole breakers and a small outdoor load center & a fused disconnect
or
b) 2 really long power runs, 2 double pole breakers, a fused disconnect and a bunch of sheet rock work & painting.

In my opinion option B seems like unnecessary work.
 
You need to put a 12×12×6 gutter box between customer side of meter and main disconnect triple barrel lugs times 3.
L1 L2 N taped with a minimum of 60 amp disconnect fused at 60amps min fused disconnect with ten ft conductor length.
I would say have an experienced licensed electrician do the tap.
I would not attempt this as a first install.


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zman990 said:
You need to put a 12×12×6 gutter box between customer side of meter and main disconnect triple barrel lugs times 3.
L1 L2 N taped with a minimum of 60 amp disconnect fused at 60amps min fused disconnect with ten ft conductor length.
I would say have an experienced licensed electrician do the tap.
I would not attempt this as a first install.
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I absolutely will have a licensed electrician on-site to perform the final terminations.
My role is to do most of the grunt work up to that point, and to learn the proper way to do things for future installs.
The gutter box was the magical piece that seems to be missing.
I was starting to wonder if the AHJ would allow the taps to occur in here:

pt3.jpg

It would be a tight fit for sure.
Again, the engineering document does not call out a gutter box. I wish the documents provided tighter details considering how much detail they ask for to even start the drawings.
This is what I have:

Plan.jpg

Leaves room for the imagination as you can see.
 
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With the insulation piercing connectors you're less likely to need the additional box, but your electrician can offer advice on the best method. The main consideration is simply adequate space for the wiring and connectors.
 
jaggedben said:
With the insulation piercing connectors you're less likely to need the additional box, but your electrician can offer advice on the best method. The main consideration is simply adequate space for the wiring and connectors.
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IPC's are another issue that you'd better consult your AHJ about before proceeding. CPS (San Antonio), for example, does not allow them to be used for making supply side connections.
 
Where is this requirement coming from, the utility?

However I must back-feed the PV into the system via a double pole breaker.

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Is the house load center MLO? If so and you do a load side tap at the main breaker you have to make sure the combination of the panel bus rating and the main breaker rating allow it.

The cleanest way I think would be to mount a fused disconnect next to the main breaker, do a supply side tap, and you are done.
 
It looks like there is plenty of room at the bottom of the main breaker enclosure to make the splices for a supply side connection. Our electrician prefers to use qty. 3 Burndy BIBD350-2 to make the splices. This is a size larger than is necessary, but it allows you to cut out the insulation in the middle of the service wire and slide the splice connector down the insulation to the stripped section. That way you can use a 2-terminal splice connector rather than one with 3 terminals, and you don't need to cut the service conductor. It's clean, compact, and quick. Not as quick as an IPC, but I think it makes for a better installation.
 
PWDickerson said:
It looks like there is plenty of room at the bottom of the main breaker enclosure to make the splices for a supply side connection. Our electrician prefers to use qty. 3 Burndy BIBD350-2 to make the splices. This is a size larger than is necessary, but it allows you to cut out the insulation in the middle of the service wire and slide the splice connector down the insulation to the stripped section. That way you can use a 2-terminal splice connector rather than one with 3 terminals, and you don't need to cut the service conductor. It's clean, compact, and quick. Not as quick as an IPC, but I think it makes for a better installation.
Click to expand...

Nice tip. Thanks for that.
 
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