Big problem with solar cable trunking.
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- Опубликовано: 8 сен 2024
- Today I decided to install the cables between the barn and the plant room. I quickly discovered that the underground trunking was full of water.
I attempted to pull the cables through but they got completely stuck. It's now looking like I'm going to have to dig up the entire length of trunking!
I also found moisture/water in my underground ductings, but it might be due to condensation with the temperature delta between seasons. However, that worries me and I am thinking of developing a way to drain them periodically. I had to pass my six cables one at a time and it was still hard. Good work though, nice to see more Victron equipment being used! 🙏thanks for sharing
Perhaps use two 4 core externally insulated cables with insulation suited to wet conditions, one for the positive wires and the other for the negative wires. The solar cables can be ferruled to the ends of the 4 core wires for the connections to the MC4 connectors at the combiner boxes.
Sarah, try this:
1/. Pull back the cable with an additional pull string or rope attached.
2/. Ensure that when the cable is pulled out, one end of the second pull string or rope is brought along with it.
3/. Attach both pull strings or ropes to the cable.
4/. Pull the cable through from the opposite end, using the "needle's eye" loop technique demonstrated in the video - see: ruclips.net/video/ZRJqaqSfPf8/видео.html
5/. IMPORTANT:
A. Make sure the bare wire after the loop is long enough to twist around the cable to secure it (twist it so that the bare wine after the 'needl'es eye' loop is wrapped, coiling away from the needle's eye' loop) - this will allow you to pull harder without risking the "needle's eye" loop becoming undone.
B. Use two pull ropes or strings to ensure greater pull and to avoid breakage of your puller (the string/rope). After looping each through your improvised wire ‘needle’s eye’ loop, tie off each string/rope to itself, thus not at the same length, so that each ‘bump’ is a distance from each other.
C. Ensure that from a span before the first bump, past the second, and past the third bump are wrapped with a continuous length of installation tape (so that they do not get caught up as you pull your cable through the plastic piping).
Pulling your cable from the other end of the plastic piping that you have laid will allow you to wiggle the cable so that it may aid you with getting your cable around those three bends that are shown in your vlog.
Good luck! : )
Pull just a couple of wires through at a time AFTER liberally applying copious amounts of cable lube (dish detergent) at both ends of the tube. Make sure wires being pulled are warm.
To my experience, you either do all needed cable at once as otherwise putting another cable later (even a single one) is basically impossible. The wires go over each other and increase the rubbing x-times. Id suggest to do all at once and put extensive lube on it. Worth 10 tries before doing a new tube.
First thing I would suggest is a cable puller. It is an ingenious wire mesh that you sleave over the cable. It is a bit like a Chinese finger trap. The harder you pull, the tighter it gets on the cable. What is great about it is it joins your rope to the cable with no knots. It is makes a smooth linear connection to the cable. If you google “cable puller” or "traction net " you will see some photos of a cylindrical wire mesh. It is SO much better than tying a knot.
You could add castor oil to the cable to make it easier to pull, there is product call Hellerine which is 94% castor oil and evaporates after installation. You could pressure test the pipe to test for leaks on this installation or the next.
Find an alternate route if you can, up and through the loft area, then back down again?
Also see if you can get an inspection camera down the pipe to see what's going on.
Cable gaine should be a minimum of 60 cms below ground level, except where there is vehicle access, then it should be a minimum of 1 metre below ground. you need to 'plug' each end of gaine too with a bouchon!
Try pulling each wire through separately, being careful not to burn the insulation. The size of the loom you’ve made will certainly make the cable drawing more difficult. Get yourself a “cobra” cable installation tool.
Yous best supplier is probably Guilloux Villedieu, or of course Cochards.
It may be collapsed. If it is, you may have problems later. Tear it up. Do it right. This time build in a inspection hole before the bends. Bury it deep enough so it will not collapse.Good luck.
I would be very wary about 'plain' PV cable in underground pipe. We have solar panels in the garden approx 40m from the house. At first the riso was ok, after a couple of years it began to drop, now after 5 years and pulling out the cable, drying it out and risking it the riso has dropped to 11Mohms or lower and a current draw of 4mA which in normal operation is ok but at sunrise the current leakage does tend to trip the RCBO. I did find that Doncaster Cables does 2 and 4 core cable for this very purpose. PV cable is not designed to be immersed in water. Best of luck.
Yes that's what I was worried about it being immersed in water precisely why I want to install a completely new cable run.
@@Gridbusters-qx4ompls realize that you will almost always have water from condensation in any underground pipe. To seal this is possible but needs to be done quickly and might not hold over the years as water has a very tiny head.
I think your diagnosis is correct, and the 90° corners are a problem too. There are many solutions, but the crushed conduit as the biggest problem if that is truly what's happened. After you dig up your existing conduit, go much deeper with your trenching and use wide, sweeping bends in the conduit. The bends in our office's conduits for large cables (like for our diesel Caterpillar generator that provides back-up power to our server room) have 1 ft. radius turns. The conduits run 3 ft. underground under a concrete pad to an electrical service room, then in overhead conduits to the server room 100 ft. inside the building. Instead of your 90° corners to run between threshold stones, go under the foundation footings and come up in your plant room. Yes, that's a LOT more work, but if the conduits are buried deep enough, trucks will be less likely to crush them too. Good luck.
Having live through this with similar bends, cable, lube is your friend! Also, make sure you stagger the wires at the front they need to be blunt and if anything bent over so there’s nothing that can get caught on a joint as you pull. in addition whoever’s at the tail end needs to coordinate a push while you pull and push with force.
Just dig up the two 90 bends in the picture. Start with the straight pipe for the cable pull
You can also get cable lube that you could try and see if that helps.
Try and pull the cable the other way... Then you can push them around the bendy bit from your side...
If the bends are only at one end, as per your photo, perhaps just dig up that half. Try to pull the cables through from there and then add the replacement trucking. Plus use some lubrication to help the cables travel through the conduit. I think you spoke of the posibility of more solar being added later, are you including the cables for this as well?
use a larger rope and some sort of a winch to pull it through the last bit. Last resort dig up. You may just need a larger rope and some more people to pull it. One at a time wont work cause they will tangle
Your correct, best rule to follow is max of two 90 degree bends between pull boxes. Instead of a string use flat mule line rated for a lot more pulling force (1600 lbs). You can also try adding cable grease as it enters the conduit.
Doesn't look like trunking to me, more like soil pipe! If you use TPC rouge cable conduit as you show in your feed from the roof, you wouldn't need bends, and it would be waterproof if laid correctly. You also need the red warning marker tape approx. 15 cms above the conduit. The TPC conduit is what ENEDIS use so it should be good enough!
You appear to have already made the decision to dig it up - and I'm not trying to dissuade you - but from my experience I reckon those four cables will get through if you stagger their joins by about 2m. That way you'll be pulling on the first cable before the second one hits the bends and so on. Only join them together close to the beginning so that you can disconnect the first one when the second one appears which will prevent the first one from being pulled through too far. Also make sure that the tape that you use makes a gentle taper up to the beginning of the next cable rather than an abrupt step. Stripping back the insulation by a few inches at the beginning of each cable helps with tapering. Also, if you attach some tape to the string at say 2m and 1m before the cable it will let you know how close to the end of the tube you're getting when you hit a snag.
Leave it or not I did stagger the joints exactly like you're explaining I did film this however for some reason my microphone was not working 😭 also there are 8 cables so it's quite a big bunch plus I might need to pull through another 4 cables in the future. That's why I'm leaning towards putting in a new tube.
@@Gridbusters-qx4om Yeh sorry, I'm really not sure why I thought there were only four cables when it'd been made perfectly clear that there were eight (honestly, I don't drink or take drugs; maybe that's the problem and I should start). The 6mm2 double-insulated PV cable isn't all that flexible (well at least the stuff I've got isn't) so it might actually be too big an ask to get eight of them around a 90degree bend. So actually, my vote would be to dig it up and do it to the high standard you're thinking of with potential for future cable runs etc. What about the existing car charger cable and any potential V2H capabilities if your husband gets the Cybertruck or something else?
as mentioned if your happy with conduit stagger each cable and then pull through . if it were me i think the only way of 99% waterproof is continual conduit no joints .
Try to pull them the opposite way. It should be easier, as the cables will bend at the beginning, and then go straight - you will have more pulling power at the 90 deg. at the beginning.
You just have to stagger the tape joints on each PV cable by about 1 metre. Tape them really well and use lots of fairy liquid on the joints when entering the duct.It's a duct no a tube! Water in the duct is normal..
Yes we did stagger the end of the cable but we did not put any washing up liquid or grease on the cable.
Stagger the cables 2 ft from each other, you will have more flex and control.
After watching the video, I was thinking the same thing stagger the cables and also, I would lubricate the cables with some dish detergent or soap detergent. Where I used to work electricians would pour some lubricant down the conduit then on the cables when pulling through 100 feet or more of conduit. I would like to see her try this before she dig up the trunking.
Search for 'Gaine TPC rouge' 90mm diameter or bigger. It's what ENEDIS use. NO bends equals no tight spots ...
You could stick a camera down a pipe and see if it’s collapsed. Did you try to run two wires at a time? You can always run your wires externally on the building inside conduit. Not the best looking, but it will serve its purpose. Then you can get a cork cutter, and go in through the brick with the LB.
Cable grease which is actually thick soap first. Pull boxes are always great. Conduit bends not water pipe bends (Els)and try hard to never exceed 360 degrees in a single run of conduit.
Just looking at your picture it should go if soaped up good. PV cable is flexible enough but the jacket is usually a little sticky. Cable soap will deal with that.
It’s not ideal, however pull each length through one at a time. With a new drawer string.
Also why are you pulling so many through?
Surely it’s only a pair of cables for each combiner box?
If you can get them through it’s a damn sight cheaper than pulling all the yard up.
Hi. Do you think it would solve the problem if the trunk of the solar cables were greased with grease intended for sanitary installations?
PS. You must use grease intended for sanitary installations only. The car grease it is not recommended because it dissolves the rubber.
Pull it in the opposite direction. Also use wire pulling soap on wires, or even dish soap at least.
yeah I would use chinese trap but I think you can go through without it just put more tape to be more smooth and also here in greece we use a lot of dish soap to slide more easily through the conduit and also leaving the cables on the sun for a couple of hours before pulling and remove the tapes from the rest of the cables to be more freely passing through the conduit it will help🙂good luck btw😅
Water in pipe is fine, happens all the time with electrical work.
Don't put any bends, one pipe. Get a 450mm Unperforated Twinwall Plain End Pipe. You need swoopy bends and really simple joins. Also silicone spray is very useful. You need to do a c shape. Expert in underground pipes. God I had a some bloody hard jobs in the past.
try greasing the cable first and pull again
do you know anyone who has a drain inspetion camera snake anothe idea tie a screwed up plastic bag or a rag to the end of the draw string put it in one end of the pipe if you have a powerful shop vac suck it through from the othe end it should bring out any muck ot grit that is blocking the pipe Good luck x
Its not ideal that the conduit is full of water so soon, but it is kinda expected to happen at some point so you need to be sure to use the correct type of cable, rated for direct underground burial. Still use a conduit (everything will last longer). I think the cable type is UF-B but don't quote me.
A 90-degree bend is impossible. You have at least three... that's impossible. And if the conduit is crushed you are kinda SOL... you'll have to rip it up and at that point you might as well rip up the whole thing. That said, it is possible to keep 90-degree bends in when laying out new conduit but you have to keep the joints separated and unglued to get the cable through each section independently, then finish the joints and glue them up. Get all the cables run through before finishing the burial.
Pull-throughs only really work for straight conduits when there is already a lot of wire in the conduit.
For pulling cables through long conduits you usually have to grease the cable bundle as you put it in, and you want to run all the cables at the same time, not one at a time. Have someone pushing the cable on one end and pulling the leader on the other at the same time.
Add about 5 feet to the cable length beyond the length of the string. At least 5 feet. Even more. The cable is not going to be completely straight in the conduit (or even close to straight), there are going to be twists and other things.
Also due to the packing of the cables in the conduit, you have to de-rate the current allowed to flow through the cables relative to their ampacity. Four strings, 8 current-carrying cables... derate to 80% of ampacity. More than that and you will be de-rating 70%, 60%, even to 50% of ampacity. You might be good here already but double-check.
-Matt
Never use 90° angles. Always insert 15° angles into each other, then you can also pull a cable through.
If there is already water in the pipe it is broken.
Then lay two new pipes, one for positive one for negative. If animals get into the pipes and chew on the cables, you will soon have a short circuit between positive and negative.
Can you use 4x6sq SWA instead. Fact there is water in pipe
I'm at 8:00 now... it looks too complicated...
If you have 4 spools, you got 8 ends. So just unspool them, pull in all wires in one time using the 8 ends, connect them on one side and then pull them a little bit back untill it fits. Then cut them to the right length on the other side and connect them as well. Thats how we do this all the time.
OK now at the end of the Video...you had no chance to get this done.
If you dig, i suggest to put in several smaller pipes. One for positive, one for negative and two or more for spare or future installations.
Don't use corners, just bend the pipe in a wide bow. Do not cut and refit the pipe anywhere, it should be in one piece.
Pull all the cables in from the other end if thats no good just dig up where the blockage is
Hire an electrician ;)
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