diy solar

diy solar

Pulling 17 wires through 230ft of conduit?

I just did a couple big wire pulls. The first was 8 10AWG wires and 2 8WG wires through about 200ft of 1" PVC. This required quite a bit of force but it was doable with wire lube. The second was the same wires plus 4 12 AWG wires through about 85ft of 1 1/4 PVC. This one was pretty easy. For both I used a nice steel fish tape made by Klein. I attempted to use poly line at first and it was impossible.
 
Mule tape. It's great for strapping down loads, bundling pipe or conduit or just about anything else, a usable clothesline in a jam, you can make a pretty decent calf halter out of it, a quick fix when something is falling off your rig and you just need to get back to the barn, and probably a thousand other things.

Also good for pulling wire.
 
rhino said:
Wanted to do a sanity check that I wouldn't be crazy to try and pull (16) 10 AWG XHHW-2 wires plus one 4 AWG (one of the existing cables which I will reuse) through 1.5" conduit over 230ft. This is an existing underground conduit and I can't redo it. I'll be pulling out the existing wire and replacing it with the wires mentioned above. It is fairly straight shot and I might even dig down and temporarily remove one of the 90 degree elbows in the field where the solar array would be located for easier pull. I've done 500ft pulls in past but with only 3 larger cables. Just wonder about the logistics of 16 rolls of cable (plus the one larger one for ground) being pulled.

This would theoretically be for 8 separate strings of bifacial panels with 6 in series (250V Vmpp) if I decide to do that many with Isc of 13.64 under STC per string. I was going to use 12AWG but realized from discussion in another thread with @Hedges that would be too low of ampacity.
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I would be very interested to find a description of your solar system system.
May be you previously described it, otherwise could comment for example:

- Do you use a combiner box with fuses or circuit breaker, surge protection, and DC disconnect switch.
- Do you have any lightning rod or grounding rods near the PV location.
- Is the additional 4 AWG used as ground? If so, how a ground wire ampacity is calculated.

- What kind of MPPT (Max VPP, Max ISC, Number of Input) and how many of them are you using at he the other end to connect the 8 PV strings.
- Do you have any kind of disconnect switch and or DC circuit breakers to isolate the MPPT input from the counduit line.

Thank you.
 
rhino said:
Wanted to do a sanity check that I wouldn't be crazy to try and pull (16) 10 AWG XHHW-2 wires plus one 4 AWG (one of the existing cables which I will reuse) through 1.5" conduit over 230ft. This is an existing underground conduit and I can't redo it. I'll be pulling out the existing wire and replacing it with the wires mentioned above. It is fairly straight shot and I might even dig down and temporarily remove one of the 90 degree elbows in the field where the solar array would be located for easier pull. I've done 500ft pulls in past but with only 3 larger cables. Just wonder about the logistics of 16 rolls of cable (plus the one larger one for ground) being pulled.

This would theoretically be for 8 separate strings of bifacial panels with 6 in series (250V Vmpp) if I decide to do that many with Isc of 13.64 under STC per string. I was going to use 12AWG but realized from discussion in another thread with @Hedges that would be too low of ampacity.
Click to expand...
I recommend renting a greenlee wire puller or what ever brand you can find. It's made to pull multiple conductors long distances. Have the person feeding the wires lubricating as they feed. Use generous amounts of lube.
Good luck
 
rhino said:
Okay.. I'm getting a bit more confidence this is doable :) Already have excess mule tape from other pulls I would use.

For background on why now; I currently have about 9kW situated on several top of pole mounts (some panels over 15 years old). This winter we've had many days of thick clouds resulting in only about 10% of normal production for that day. Fossil fuel generator is also not an option for reasons won't delve into here. Currently grid-connected in order to make up for the shortfall. Plan is to disconnect from the grid this summer since utility company is planning on doing work this summer that we don't want. So I am left with needing significant PV production for maintaining all loads even during these cloudy winter days.

I was looking at using either 24 or 48 of the 540W Vikram bifacial panels. Specifically looking at these since they are made in India instead of China. Would be put on a seasonally adjustable (up to 60° tilt) Sky-Rack 2.0 ground mount from Sinclair Designs. After talking with them they said those larger panels would need to use their 8 panel mount sections and since I would be using 6 panels per string I'm left with multiples of 6 and 8 hence the 24 or 48. Already in the Victron ecosystem so would use 1 or 2 of the SmartSolar 450/200 (4 independent trackers per controller). Usually hit -40 or lower in winter so have to watch that Voc and therefore the 6 panels per string only. 24 likely would be enough for now but don't want to have to expand again 5-10 years from now when everyone has EV's ;)
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I understand with those size panels you have to limit your string size to 6 or maybe 8, but are you not paralleling any of the strings ? This keeps the voltage the same which is your limiting factor and just doubles the Amps. If your controller and MPPt’s can (I have no idea about your controller or its series string amp limits) handle paralleling those strings then you can save money and wire in the pull by half. Instead of 16 wires you could be pulling in 8 if you can parallel strings.
 
Okay.. I tried pulling the three #4 gauge cables in the existing 1.5" conduit and they aren't budging :(.. The conduit has been in the ground for maybe 15 years. I may have to put in new conduit?
 
What force?
Look up allowed tension and try a comealong or jack or something.

I managed to hand pull a tight bundle of 12 awg by wrapping it around a pipe and using that for leverage.

I wonder if there is a way to blow a mist of lube through?
 
I'll try putting a vacuum on the end to at least see if there is some air flow so I know it at least isn't completely filled with something. Only worry with pulling too hard is I would hate to damage the cable if there is something "wrong" with the conduit.. either broken somewhere or bent a lot.. It does go under a gravel driveway.
 
Might also cut off the vertical end of the conduit since I would have to move the pipe slightly over anyways and would be able to pull directly in line with the conduit that way. I do have 2" conduit of enough length but would have to hand dig the entire trench since it goes through some brushy/treed areas where I'd have to limit any damage.

n2aws said:
Also, don't forget to add lube. and more lube. you may wanna see if you can buy a 55g drum of it.
Click to expand...
I did get lube for when I put the new cable in.
 
This is good example of why you should heed all the warnings people say on here to put in another empty conduit while you have the trench open "just in case".. ;)
 
rhino said:
This is good example of why you should heed all the warnings people say on here to put in another empty conduit while you have the trench open "just in case".. ;)
Click to expand...
I'm a huge fan of spending the extra to make life easier later.. that said, 16 10 AWG wires shouldn't be a horrible pull. Just google how to do a strain relief, and you should be fine.
 
Worst-case, if you just can't get it to move.
Locate the center of the run. And dig it up, and cut the conduit. You should have much better luck only dealing with half of the run.
Then you can add a pull box. Or just repair it, before pulling in the new conductors.
Once the old conductors are out. Swab the conduit well. This will make it easier for the new pull.
 
rhino said:
Might also cut off the vertical end of the conduit since I would have to move the pipe slightly over anyways and would be able to pull directly in line with the conduit that way. I do have 2" conduit of enough length but would have to hand dig the entire trench since it goes through some brushy/treed areas where I'd have to limit any damage.


I did get lube for when I put the new cable in.
Click to expand...
Yeah, even one 90 in that distance. Not fun.
 
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