sunny boy inverter?

[mudhole]

i just read this, since i am running MC4 wire to the inverter , i am not "required" to use conduit? am i reading that correctly? basically my inverter is directly underneath the array.

The general rule states that the DC source and output circuits from a PV array shall be contained in metal raceways, MC cable that complies with 250.118(D), or metal enclosures from the first point of penetration to the first readily accessible disconnecting means. One of the clarifications addresses that this requirement is intended for the DC circuits only — not any AC circuits associated with the inverter’s output. The inclusion of MC cable was new to 2011, so be sure to make sure your AHJ is accepting that change if you plan to use this wiring method.

[mudhole]

nevermind...another rookie mistake, confused MC connectors for MC cable, can i just run the DC cables through the roof with pvc conduit to the inverter?

[Ampster]

That is a question for the AHJ. I don't know the specific answer for your jurisdiction. I have seen commercial solar farms do it without conduit in California. But those were protected by a fence. There are some NEC provisions about exposed wiring within reach of a human. Conduit fill table may also be different for exterior. Then there is the requirement for metal conduit that ma apply..

[mudhole]

how tight do you want the panels on the roof, touching?

[Ampster]

how tight do you want the panels on the roof, touching?

It depends on thermal expansion. Most clamps allow for thermal expansion and define how tight the panels are based on the bolt diameter. On my patio cover it was easier for me to clamp from below so I have no space between my panels but I don't recomend that unless one has a few panels. . The entire length of that system is only 7 panels and my temperatures vary from 30 degrees to perhaps 120 degrees for the panels. I have not notice any stress from thermal expansion. Your mileage may vary

[mudhole]

is there any disadvantage to running 1 mppt input at around 300v dc in and the other feed around 180 v dc in? (the dc input range for the inverter is 125-550v per mmpt input)

also just trying to sequence everything, i have the inverter installed on the wall, i have all the rails up, all i need to do is put the solar panels up , clamp them in and plug them in...(i still have to run the ac out to the disconnect). do most people cover up the solar panels as you plug them in? i read that somewhere, but all the videos just show people plugging them in as they go...

[mudhole]

well crap, my solar extension cables are not going to be in until monday, i assume that i can still wire all the panels and just leave the leads to the inverter "hanging" wrapped in electrical tape and tucked under last panel just in case it rains?

[Mike90250]

Do not allow the un-connected MC-4 connectors to get wet. When mated, they have O ring seal to keep parts dry, but if the innards get wet, they quickly corrode,

[Ampster]

is there any disadvantage to running 1 mppt input at around 300v dc in and the other feed around 180 v dc in? (the dc input range for the inverter is 125-550v per mmpt input)

........ do most people cover up the solar panels as you plug them in? i read that somewhere, but all the videos just show people plugging them in as they go...

I don't know the specifics of your inverter. My inverter has two inputs but actually only one MPPT channel so in my case it would not make any difference. My inverter has a much higher minimum voltage than yours. Did you decide on that configuration using your inverters string sizing tool?

The following is not based on any in depth knowledge of an actual MPPT curve but I would prefer to have one string running at a higher voltage than two strings at lower voltages. That is assuming that there is a safe margin at the top so on a clear sunny day at low temperatures the max voltage will not be exceeded. The only other reason some people have two strings on separate channels is if they have different orientations. In that case the MPPT curves would be different for each string depending on the time of day.

As far as plugging them in, I just make sure the breaker is off so there is no load to create a spark and damage the contacts.

[mudhole]

1. my sunnyboy inverter diagram for split 240 shows only ground coming via home panel (house ground), i thought i read somewhere where you dont want your equipment on separate earth grounds?

2. my disconnect does not have a neutral ground lug, do i need to get another type disconnect with L1, L2 , N and ground?

[mudhole]

nevermind number 2, i went and purchased the correct one.

to clarify my question number 1 the instructions from sma, it says to ground the AC out on a lug and the rails/panels to a lug on the inverter as well, do i also run a special ground rod for all the equipment?

[Ampster]

1. The house ground presumably connects to your earth ground at the main panel. You can have multiple devices or wires connected to your earth ground but not multiple earth grounds

2. There is no need to switch the neutral. The neutral is never switched in 120 volt circumstances and the same logic applies. If you saw switchgear with three legs, it was probably for three phase motors.

[mudhole]

ok, so no ground rod at the panels, just run them via the ground through the inverter to the panel.

[Ampster]

ok, so no ground rod at the panels, just run them via the ground through the inverter to the panel.

Yes, but pay attention to the wire gauge requirement. If I recall, many jurisdictions require at least 8 AWG. Any splices need to be crimped so they are more permanent.

[mudhole]

i have the sunny boy 5.0 -41, i am confused with the installation book, is the multi function relay necessary to compete the install?