Conduit for dual SMA Inverters going to one breaker box

[khanh dam]

Below is my proposed conduit layout for an OUTSIDE dual inverter system.
I plan to use 1" EMT with pull through elbows and raintight fittings.
Since there is no such thing as a "T" connector I used a 6x6" PVC junction box instead.

Does this seem like a good way to run all the wires? Red indicates the AC wires. The DC wires are in the black conduit runs.

Last system I did had the 200A breaker box in the middle of the 2 inverters, but can't do that at this house and having both inverters on same side makes it harder to run all the wires.







sunnyboy conduit layout.png

[SunEagle]

I guess my question is can you connect 12000 watts of inverters to a 200Amp panel? I would think you will exceed the maximum allowed amperage that 12kw can generate at 240 volts.

[khanh dam]

it's a 10KW array, the inverters are undersized..

[solarix]

Doesn't matter what size the array is - the NEC and your utility go by inverter output rating. The biggest inverter you can back feed into a 200A panel (without derating its main breaker or doing a line side tap) is 7.7kW.
Also, your utility is going to want a single disconnecting means on the AC side. You need to put in a load center box to combine the inverter's output to feed a single AC disconnect feeding the backfed breaker.

[khanh dam]

thanks for response. main breaker will be de-rated to 150A so no issue with back feeding it. Never heard of needing to combine 2 AC disconnect switched into a single one. Last one I did in Florida passed with dual ac breakers, but maybe I did it wrong back then. What part of NEC covers that?

[khanh dam]

690.14 says up to 6 disconnect switched can be used. Am I interpreting that incorrectly?690.14.png

[solarix]

Its not a code rule, but is required by most utilities. Check on the interconnection requirements for yours...

[PVAndy]

Its not a code rule, but is required by most utilities. Check on the interconnection requirements for yours...

The more common way to do it is a small sub panel with 2 40A breakers and then one disco into main panel

If you use 2 disconnects you would need to label them as 1 of 2. And 2 of 2

Andy

[SunEagle]

The more common way to do it is a small sub panel with 2 40A breakers and then one disco into main panel

If you use 2 disconnects you would need to label them as 1 of 2. And 2 of 2

Andy

It still comes down to what the AHJ wants and will approve.

[Lynx]

The residential electric code does not apply to utilities. They can require things in addition to local codes. The state negotiates the rules with the utilities.

you mention outdoor but not “what” is outdoor. EMT is not approved for outdoor use last I checked. You could use PVC though in many cases.
The size pipe is dictated by the size and number of conductors. There are tables in the NEC.

[khanh dam]

EMT is fine for outdoor use as long as you use rain tight fittings. AHJ approved it. Ironically I might tear it all out and reloate it under the ground mount pergola so I don't have to spend $1000 on rapid shut down stuff.

[PVAndy]

The residential electric code does not apply to utilities. They can require things in addition to local codes. The state negotiates the rules with the utilities.

you mention outdoor but not “what” is outdoor. EMT is not approved for outdoor use last I checked. You could use PVC though in many cases.
The size pipe is dictated by the size and number of conductors. There are tables in the NEC.

NEC does not allow EMT in "WET" locations. On a roof or the side of a building is not a wet location. You must use couplings rated for outdoor use. We use EMT all the time between arrays on roof and building exteriors/ Also note all DC conductors on buildings need to be in metallic conduits or have metallic sheathing.

Andy