sunny boy inverter?

[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,

[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?

[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...

[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]

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

[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]

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?

[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.

[Ampster]

i watched the iron ridge bonding/grounding video, i get it now, the panels are bonded to the rail via the end and mid clamps, i dont actually have to screw a lug into the panel and run the wire through it,. i just need to bond the rail via lug and any splices and run them to earth ground via 6 awg bare copper.

as far as code goes, can i use pvc conduit for both the dc and ac lines?

Check the Iron Ridge splices, they may do the bonding with the way the screws self tap. At least that was my assumption on my last self install from what I read about my particular rail. On an earlier UniRac system I self installed bonding straps were required.
Double check the code and labeling requirements but I am pretty sure the AC and DC have to be in separate conduits. Every jurisdiction has its own interpretation. In one jurisdiction where I had solar installed and did a self install, the DC had to be in EMT or Rigid and could not even be in flexible conduit. I think DC has to be labeled differently because of potential for much higher voltages.

[mudhole]

i watched the iron ridge bonding/grounding video, i get it now, the panels are bonded to the rail via the end and mid clamps, i dont actually have to screw a lug into the panel and run the wire through it,. i just need to bond the rail via lug and any splices and run them to earth ground via 6 awg bare copper.

as far as code goes, can i use pvc conduit for both the dc and ac lines?

[mudhole]

Yes, that is what I meant by, "bond each rail to ground." Did that answer your question?

I usually buy an extension cable of the correct length and cut it at the appropriate spot. Then you have two cables one with a connector for the positive and one for the negative. the cut ends each go through a cable gland into the junction box. Note, the wire length of these will be different depending on how you connect the panels and if you have a single row of panels (or an odd number of rows). If you start at one end and daisy chain then you will have one short and one long part of the extension cable if your jbox is at one end. There is a process if your panel cables are long enough where you alternate panels going down to the end and pick up the unconnected panels on the way back. I wish I had a picture which someone on another thread posted. That method saves wire.

No worries, that is how these threads become a valuable resource for others. I learned that cable saving trick just a few months ago on this forum after I had wired my single row of panels on my patio cover.

ahhh, i think i understand what you are saying with skipping, that way both leads are next to each other (connect 1,3,5,7,9 in one directions, 8,6,4,2 coming back. i will need to order 2 extensions since i am running them into separate mppt inputs.

[Ampster]

gotcha on 1 and 2, on 3 however, if the rail is coupled, i probably have to bond that?

Yes, that is what I meant by, "bond each rail to ground." Did that answer your question?

also , are there special connectors to use for the ends of the panels?, for when i am done connecting them in series, i will have a positive and a negative lead , are there specific connectors that plug in to the panel lead and then are just wire to the inverter for the dc in?

I usually buy an extension cable of the correct length and cut it at the appropriate spot. Then you have two cables one with a connector for the positive and one for the negative. the cut ends each go through a cable gland into the junction box. Note, the wire length of these will be different depending on how you connect the panels and if you have a single row of panels (or an odd number of rows). If you start at one end and daisy chain then you will have one short and one long part of the extension cable if your jbox is at one end. There is a process if your panel cables are long enough where you alternate panels going down to the end and pick up the unconnected panels on the way back. I wish I had a picture which someone on another thread posted. That method saves wire.

sorry for all these rookie questions, i have not been able to find a video that addresses these things

No worries, that is how these threads become a valuable resource for others. I learned that cable saving trick just a few months ago on this forum after I had wired my single row of panels on my patio cover.

[mudhole]

1. The AC disconnect has to be on the outside and have air gap. You will also need a breaker at the panel where that circuit attaches to the bussbar. It would be redundant and expensive to fuse the external disconnect.
2. My inverter has a DC disconnect. If yours has one you don't need another one unless required.
3. The easiest way is to buy the clips that are engineered to do the bonding of the panel to the rail. Then you only need to bond each rail to the ground.

gotcha on 1 and 2, on 3 however, if the rail is coupled, i probably have to bond that?

also , are there special connectors to use for the ends of the panels?, for when i am done connecting them in series, i will have a positive and a negative lead , are there specific connectors that plug in to the panel lead and then are just wire to the inverter for the dc in?


sorry for all these rookie questions, i have not been able to find a video that addresses these things

[Ampster]

help with the nuts and bolts of the system

1. i am running 2, 9 panel systems , roughly 300 volts each, into separate mppt inputs on the inverter, I know i need an AC disconnect, should it be fused/breaker?

2. i think i should also put in a DC disconnect before the inverter so if i ever have to do work at it, i can open the circuit, I am assuming this is typical?

3. what is the easiest way to bond the rails/panels?
..........

1. The AC disconnect has to be on the outside and have air gap. You will also need a breaker at the panel where that circuit attaches to the bussbar. It would be redundant and expensive to fuse the external disconnect.
2. My inverter has a DC disconnect. If yours has one you don't need another one unless required.
3. The easiest way is to buy the clips that are engineered to do the bonding of the panel to the rail. Then you only need to bond each rail to the ground.

[mudhole]

help with the nuts and bolts of the system

1. i am running 2, 9 panel systems , roughly 300 volts each, into separate mppt inputs on the inverter, I know i need an AC disconnect, should it be fused/breaker? ,

2. i think i should also put in a DC disconnect before the inverter so if i ever have to do work at it, i can open the circuit, I am assuming this is typical?

3. what is the easiest way to bond the rails/panels?

thanks in advance for any and all help