THHN / THWN OK? (Transition is to #4) or Solar Cable, Welding Cable, etc (200 ft / 1" PVC / Schedule 80)

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#10 AWG MC4 (Panels)
#4 AWG - Run to House (200 ft) (Underground & Free Air)
Disconnect or Combiner Box? (only really have 2 panel leads - Already 2S2P so 2 leads into box)
200 Ft 1" PVC (Schedule 80 "protection from physical damage / above ground" naturally is my smallest I.D.)...The rest underground is schedule 40

IS THHN OK TO USE? -- I guess my real question (Didn't Buy The Cable Yet)

just for refference (everyone asks...lol)
4 Panels (2S2P) ("Possibly" future 4 more) - https://us.qcells.com/q-peak-duo-xl-g10-bfg/
Whimpy get cha by solar generator - (150 V / 2,100 W Solar Input Max - https://oupes.com/products/oupes-mega-3-home-backup-portable-power-station-3600w-3072wh

I had asked this before but most answers were to just use #10. No. I'm not cheating (especially future) so I plan to run #4 AWG = 3% Voltage Drop (at 100 VDC)

THICK CABLE! -- Naturally, Welding Cable / Solar Cable? is thicker and I only have 1" Schedule 80 PVC. I installed the conduit run years ago underground to house so that's what I have.

I do hear many have used standard THHN / THWN ... My one problem to tackle would be the transition in which I would search for a disconnect (or Combiner Box?) at panels that would incorporate a #4 Bus / Termination or make one myself.

.... I guess I will figure out Disconnect or Combiner, Bus termination at panel / inside house (#4 Transition to my whimpy 15 A Max Andersons ((( LOL )))

Love to (u$e / afford) Welding Cable (400 Ft !) as it's fine stranding makes for great termination contact / flexibility but I guess I would be curious if is rated for UNDERWATER ? .... All underground conduit has WATER. ... Not to mention,... I doubt 2 would fit in my conduit.

OR,... Should I just purchase #4 Solar Cable? --- It's only difference? (more strands?) - More durable, thicker insulation and tinned copper conductors.

Of course many have this question so forgive me. (I have searched some other posts)

400Ft of cable i$ a lot so only wish to do this once.

Maximum # of Conductors / #4 THHN / 1" Shedule 80 --- is ((( 3 ))) ....Already fighting for space.

 

[robbob2112]

#10 AWG MC4 (Panels)
#4 AWG - Run to House (200 ft) (Underground & Free Air)
Disconnect or Combiner Box? (only really have 2 panel leads - Already 2S2P so 2 leads into box)
200 Ft 1" PVC (Schedule 80 "protection from physical damage / above ground" naturally is my smallest I.D.)...The rest underground is schedule 40

do yourself a favor and use 1.5" or 2" and put an extra set of conductors in there if you think there is ever a possibility of expanding the solar array.

IS THHN OK TO USE? -- I guess my real question (Didn't Buy The Cable Yet)

Yes, fine

just for refference (everyone asks...lol)
4 Panels (2S2P) ("Possibly" future 4 more) - https://us.qcells.com/q-peak-duo-xl-g10-bfg/
Whimpy get cha by solar generator - (150 V / 2,100 W Solar Input Max - https://oupes.com/products/oupes-mega-3-home-backup-portable-power-station-3600w-3072whttps://oupes.com/products/oupes-mega-3-home-backup-portable-power-station-3600w-3072wh
I had asked this before but most answers were to just use #10. No. I'm not cheating (especially future) so I plan to run #4 AWG = 3% Voltage Drop (at 100 VDC)

#10 is good to 30 amps, oversizing to reduce cable losses never hurts, but you can get the same effect by just increasing the voltage and running all series if the MPPT will take it.

THICK CABLE! -- Naturally, Welding Cable / Solar Cable? is thicker and I only have 1" Schedule 80 PVC. I installed the conduit run years ago underground to house so that's what I have.

Sorry to hear that - do you have a string or something in there to pull wire with?

I do hear many have used standard THHN / THWN ... My one problem to tackle would be the transition in which I would search for a disconnect (or Combiner Box?) at panels that would incorporate a #4 Bus / Termination or make one myself.

Combiner box out at the array
put breakers for disconnect per string and a larger breaker for the #4 wire.
SPD for surge protection
ground bar connected back to the house
maybe a straight disconnect switch in it and instead of b

.... I guess I will figure out Disconnect or Combiner, Bus termination at panel / inside house (#4 Transition to my whimpy 15 A Max Andersons ((( LOL )))

Love to (u$e / afford) Welding Cable (400 Ft !) as it's fine stranding makes for great termination contact / flexibility but I guess I would be curious if is rated for UNDERWATER ? .... All underground conduit has WATER. ... Not to mention,... I doubt 2 would fit in my conduit.

Read the ratings, welding wire may be good for wet environments but for that length of run I would just use THWN and be done with it, cheaper and simpler

OR,... Should I just purchase #4 Solar Cable? --- It's only difference? (more strands?) - More durable, thicker insulation and tinned copper conductors.

Of course many have this question so forgive me. (I have searched some other posts)

400Ft of cable i$ a lot so only wish to do this once.

Maximum # of Conductors / #4 THHN / 1" Shedule 80 --- is ((( 3 ))) ....Already fighting for space.

From the NEC table 310.16 - ampacity of wire in conduit



Elsewhere it talks about derating the capacity if more than 3 conductors

You need two for the panels and 1 for the EGC.

It is possible to fit 3 x #4 wires in the 1" conduit but better to go down one size and make the pull easier.

Also get a lubricant to pull with - you need to get the wires so they slide in... so lay them out straight... have one person lubing and feeding them into the conduit... have the other person pulling.

 

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Yep, and thanks.
Unfortunately the 1” PVC is what I got to work with.
Mule Line (w foot markers coming today) …I will **vacuum pull string in… **Pull the Mule Line in ( measurement = wire length + a little extra of course) ** Mule Line pulls THHN through,…. Taking a future pull string along for the ride… but,… she’s packed at this point! ////
Looks like I have to purchase stranded Grounding Conductor…. Wasn’t going to bother ( …like you don’t ground your DC Car do you!?) …. But,… It will be there snyway

 

[rhino]

Taking a future pull string along for the ride

As was pointed out to me in past, you shouldn't do that because you would likely ruin insulation of existing wires trying to pull more wires through. You have to pull all the wires out then add the additional wires and pull them all back through together.

 

[robbob2112]

Yep, and thanks.
Unfortunately the 1” PVC is what I got to work with.
Mule Line (w foot markers coming today) …I will **vacuum pull string in… **Pull the Mule Line in ( measurement = wire length + a little extra of course) ** Mule Line pulls THHN through,…. Taking a future pull string along for the ride… but,… she’s packed at this point! ////
Looks like I have to purchase stranded Grounding Conductor…. Wasn’t going to bother ( …like you don’t ground your DC Car do you!?) …. But,… It will be there snyway

The EGC is to keep the panel frames/mounts/combiner box all at the same potential as the rest of the system. Keeps you from getting zapped and keeps the system from getting zapped by nearby lightning

You can't pull more wires later for two reasons -
1. it will rub the insulation of the existing wires, maybe create a short
2. you have filled the max number of conductors in that conduit.

So just pull the 3 wires and be done with it.

If you did have the 2" conduit you would still only pull the wires you needed and if you decided to add later you can attach pull string to the end because you have to pull all the wires out and put them + the new ones back in as a bundle.

 

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The EGC is to keep the panel frames/mounts/combiner box all at the same potential as the rest of the system. Keeps you from getting zapped and keeps the system from getting zapped by nearby lightning

You can't pull more wires later for two reasons -
1. it will rub the insulation of the existing wires, maybe create a short
2. you have filled the max number of conductors in that conduit.

So just pull the 3 wires and be done with it.

If you did have the 2" conduit you would still only pull the wires you needed and if you decided to add later you can attach pull string to the end because you have to pull all the wires out and put them + the new ones back in as a bundle.

As was pointed out to me in past, you shouldn't do that because you would likely ruin insulation of existing wires trying to pull more wires through. You have to pull all the wires out then add the additional wires and pull them all back through together.

Yeah,... She's maxed anyway.
... When the NEC says a max Conduit Fill, you can bet it's a tough pull. -- Fortunately, I only have 2 90s then the LBs. 2 of these then free air in between (garage ceiling & basement ceiling) ...Whether I'm doing this to perfect code who cares... Time is short anyways. ----- Past experience with Industrial Electrician,... sometimes pulling 750 Kcmil (copper the size of a quarter!...This is kids stuff...lol?)
Right now I have a 150V Solar Max Input. Can't series / raise voltage at this point now. ...Hence the best wire size (for "this) and certainly would cover should I get into a real system. ...Was my thinking. $... Ugh (Wire?... Goes another thou$and)
===== Thanks guys,... I'll go with the THHN (and... "Soap-A-Dope")

 

[robbob2112]

Yeah,... She's maxed anyway.
... When the NEC says a max Conduit Fill, you can bet it's a tough pull. -- Fortunately, I only have 2 90s then the LBs. 2 of these then free air in between (garage ceiling & basement ceiling) ...Whether I'm doing this to perfect code who cares... Time is short anyways. ----- Past experience with Industrial Electrician,... sometimes pulling 750 Kcmil (copper the size of a quarter!...This is kids stuff...lol?)
Right now I have a 150V Solar Max Input. Can't series / raise voltage at this point now. ...Hence the best wire size (for "this) and certainly would cover should I get into a real system. ...Was my thinking. $... Ugh (Wire?... Goes another thou$and)
===== Thanks guys,... I'll go with the THHN (and... "Soap-A-Dope")

Assuming the conduit is slip jointed make sure to pull from the correct end so you don't snag on every joint.

 

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Assuming the conduit is slip jointed make sure to pull from the correct end so you don't snag on every joint.

It's both (downward / overlap... like a downspout) so the head will encounter both. and butt joint couplings so. With a nice sleek head made up.... no biggie. .....Besides,... I forgot how I laid the pipe 10 years ago! ...lol

 

[robbob2112]

It's both (downward / overlap... like a downspout) so the head will encounter both. and butt joint couplings so. With a nice sleek head made up.... no biggie. .....Besides,... I forgot how I laid the pipe 10 years ago! ...lol

I think I would dig at one end 10ft from the bend to find the joint and see which way if goes

 

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((( WOW )))

 

[wpns]

do yourself a favor and use 1.5" or 2" and put an extra set of conductors in there if you think there is ever a possibility of expanding the solar array.

Indeed! I just rewired an array that had three strings combined at the array to two strings combined at the array and one separate. Because there was a spare pair it was nearly trivial to do.

 

[Snaketzu]

#10 AWG MC4 (Panels)
#4 AWG - Run to House (200 ft) (Underground & Free Air)
Disconnect or Combiner Box? (only really have 2 panel leads - Already 2S2P so 2 leads into box)
200 Ft 1" PVC (Schedule 80 "protection from physical damage / above ground" naturally is my smallest I.D.)...The rest underground is schedule 40

IS THHN OK TO USE? -- I guess my real question (Didn't Buy The Cable Yet)

just for refference (everyone asks...lol)
4 Panels (2S2P) ("Possibly" future 4 more) - https://us.qcells.com/q-peak-duo-xl-g10-bfg/
Whimpy get cha by solar generator - (150 V / 2,100 W Solar Input Max - https://oupes.com/products/oupes-mega-3-home-backup-portable-power-station-3600w-3072wh

I had asked this before but most answers were to just use #10. No. I'm not cheating (especially future) so I plan to run #4 AWG = 3% Voltage Drop (at 100 VDC)

THICK CABLE! -- Naturally, Welding Cable / Solar Cable? is thicker and I only have 1" Schedule 80 PVC. I installed the conduit run years ago underground to house so that's what I have.

I do hear many have used standard THHN / THWN ... My one problem to tackle would be the transition in which I would search for a disconnect (or Combiner Box?) at panels that would incorporate a #4 Bus / Termination or make one myself.

.... I guess I will figure out Disconnect or Combiner, Bus termination at panel / inside house (#4 Transition to my whimpy 15 A Max Andersons ((( LOL )))

Love to (u$e / afford) Welding Cable (400 Ft !) as it's fine stranding makes for great termination contact / flexibility but I guess I would be curious if is rated for UNDERWATER ? .... All underground conduit has WATER. ... Not to mention,... I doubt 2 would fit in my conduit.

OR,... Should I just purchase #4 Solar Cable? --- It's only difference? (more strands?) - More durable, thicker insulation and tinned copper conductors.

Of course many have this question so forgive me. (I have searched some other posts)

400Ft of cable i$ a lot so only wish to do this once.

Maximum # of Conductors / #4 THHN / 1" Shedule 80 --- is ((( 3 ))) ....Already fighting for space.

If solar DC leaves a structure or ground mount to travel to another structure to get to the inverter, there should probably be a DC combiner box if multiple strings, and then a DC disconnect that provides overload protection if there isn't a combiner box that does so. The wires leaving this disconnect can then be sized for the total amperage of the DC system. Jumping from one string with #10 to #4 is a bit excessive (maybe) but you have done your calculations for voltage drop. If you add panels in the future you can probably extend that string in series to increase the voltage somewhat, this will probably not increase the amperage and will actually decrease voltage drop. At some point you will have to go to multiple strings in parallel but again the voltage can be used to control the amperage.
I think #4 THHN works good in this situation, it is sufficiently future proof for anything but an extremely large system. There is absolutely no reason to run PV cable or anything else for this application, indeed the insulation ratings might not even allow it (be aware that by going underground conduit you will be using the THW/THHW portion of combination insulation rating as THHN alone isn't rated for wet locations). Be sure to seal your underground conduit at both ends with duct seal to prevent moisture from invading your inverter, junction boxes, or any other equipment.
Don't forget you need a #6 copper conductor in that conduit as well for your grounding electrode conductor. The frames of the panels need to be tied to the neutral of the inverter and according to NEC 705 this is considered a grounding electrode conductor not a bonding conductor so #6 is the minimum size. 705 allows you to combine the grounding electrode conductor and the equipment grounding conductor functions on the same wire IF it is sized appropriately and IF it meets the requirements of either being continuous or only spliced in listed pressure connectors, so you don't need two wires.

 

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Very informative. Thank you for taking the time! (It's cool when you know something you love to "Teach" and share.)
I was going to post another: (still might)
GROUNDING - WHY - HOW ? .....There isn't even a spot for it. (Portable Generator)

I'm pretty sure you are thinking (and covering) a "real" system which is great.

You might know? (at the moment / but future proof desiring) I have a "get cha by" Portable. OUPES MEGA 3 (3,072 Wh, 3,000W, 7,000W Surge, 150V / 2,100W Solar Input Max ) ........ Of course there are only 2 solar leads (and a very small 15A Anderson ...lol). I guess you could say I'm starting out (emergency refer, freezer, food, plus a little extra) but very unimpressed with these super expensive portable panels (that cost the same as my 4- 485W Bifacials) and all I hear (on the ECO-FLOW forums, which in my opinion is an overpriced scam with little re$ults and heart broken customers with their "400W" power generation capabilities) but I have joined that club (money pertaining of course) but at least have some decent panel capabilties. OUPES (for an easy $1,000 less) at least had a decent input range (compairable to the other $3,000 models)...Sheeze.

First of all - I am not grid tied and never choose to be in "any" case. Survival Only.

GROUND "ING" = Earth
GROUND "ED" = Nutral Conductor ...Which heads back to supplier for re distribution... (favoring larger Nutral conductor / least resistance as opposed to the "smaller" GROUND "ING" Conductor or ROD) ....Some people don't know this but the unused power will "go back" to the company because the bigger (#2 AWG) nutral is the easier path. It won't even consider the (#10 AWG) Earth Path.... But they get them back via earth eventually anyway.

(earth) GROUNDING PANEL FRAME(s) - Understandable - (Although there was one youtuber who refused (DC - as in a "Car").
... I can understand this (if the solar panel actually should "ever" touch it's frame but it is "Isolated")
.... There is no "ground" on panel wires (just Positive & Negative)
... Again I could only see this as a safety should I touch a panel shorted to its frame.... Yes,... You Better!

? - Would I Ground Panel Frame (into the dirt)... Head inside and ground to ROD? (which is redundant) or NUTRAL? (which isn't even part of the same system... I am not using a transfer switch which would naturally now tie my stuff (nutral wise) to my house system. I would be plugging each appliance into the generator (Isolated)
PARALELL PATHS Of Earth Current (Between the 2 ground rods) But of course my frames outside have no current on them so there is really nothing there.

I WILL RUN A GROUND WIRE ANYWAY - (Future) ? ... Just hard to picture (being panels do not really have a ground "ed" system)...Like the power company.

Again, I guess you might be thinking like a professional like I have a house panel / tied / transfer switch type system.

-----------------------------------------------------------------------------------------

I also might just consider a smaller #6 (which at my 108 V still avails me 4% Drop) ...I would run the same size conductor for ground... Why cheat.

Pardon my babbling by the way,...
... I might be wrong but from what I gather:

1) - Ground That Panel Frame (via ROD) --- Or you might be real sorry one day.
2) - Run A Ground Wire Inside (For Future)? ... I would be stupid not to now.
3) - BOND ? - The Panel Frame To The Ground Wire Running Inside -
.... I just don't know what I'd do with it?

..... Like a "Sub Panel" (out in my garage) One does NOT install 2 GROUND RODS.... They run an isolated ground and all is sorted at the house panel (Bonding / Grounding / Grounded) .... Otherwise you will have Paralelled Currents.

Thanks for your reply brother. ---- A little more for me to learn for sure!

 

[Snaketzu]

? - Would I Ground Panel Frame (into the dirt)... Head inside and ground to ROD?

There is a big difference between grounding and bonding and even most electricians don't understand the difference, in my experience.
In this case, your inverter is supposed to have ground/arc fault protection on the DC side to prevent any possibility of arcing (which can easily start a fire, especially on a rooftop mount) but it doesn't work if there isn't a path for the fault current. So the metal frames and rails need to be bonded and all of the metal components need to be at the same potential and provide a path for fault current. Fault current isn't trying to go to ground, it is trying to get back to the common of the system that created it.
There is also the potential of lightning. This is what grounding is for, providing a path to earth ground. You don't have to drive a separate ground rod for your solar panel array but it doesn't hurt anything, either.
Never EVER drive a ground rod at two locations and use that in lieu of the required bonding/grounding conductor. The earth does not make a good conductor. It generally adds enough resistance that it acts as a load, which means that current can start leaking and the fault can't clear because the OCPD isn't overloading. This causes a major electrical safety issue in the system.
Don't skimp on your grounding and bonding. It is the safety system for electrical installations.

You can run two wires in a solar system install, one for bonding and one for grounding, if you like. Code requires all of the grounding electrodes of multiple systems tied together to also be tied together. Code also allows you to use the required grounding conductor as the bonding conductor as long as all of the requirements of both types of conductors are met. This causes a lot of confusion with electricians who generally try to just treat it as a bonding conductor and end up violating multiple Code requirements.
So you need a "ground" wire between all of your solar system components and your house panel. It can serve as the Grounding Electrode Conductor (GEC) and the Equipment Grounding Conductor (EGC) simultaneously BUT it must meet all of the requirements for BOTH types of conductors. That means #6AWG CU / #4 AL is the minimum size, it must be continuous or be terminated in a listed pressure connector (no wire nuts; grounding bars or chair lugs only), and it must bond every metal box and equipment enclosure. It must also have a wire or busbar path to the neutral in the AC system, meaning it can't rely on continuity of a metal enclosure, including the bonding screw. Many many people including electricians will land their grounding electrode conductors (GEC) on a ground bar in the service panel and then install the bonding screw and think this is fine. Many inspectors don't catch this, either. It doesn't mean it is right. I teach all of my electricians to always land grounding electrode conductors (GEC) on the neutral bar in the service panel to avoid this problem.

 

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What about a portable (isolated) generator?

That was a lot to digest but thank you. I'm still trying to process.
Of my experience I guess I've always split the two terms "Ground(ing)" & "Ground(ed)". (I remember it by perhaps the "sound" a hammer would make hitting a metal "Rod" = ("ding") Groun ding... Is the "supplimental" path should the other (nutral) not suffice. Any Ground(ed) conductor would be connected to the nutral bus.

Perhaps also is that DC is a different world altogether.... like a loop.

Must study more and that was very informative. Till I grasp this (or purchase and run wire before) I will run 3 conductors (Red, Black, Green)... All will be #4 or all will be #6.

---- Hope that has me ok until I grasp this.