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Post by northernfarmer on Mar 17, 2022 10:21:34 GMT -6
I was looking up USEB and USEI to see what the differences were and they certainly are two different styles although they both have the black plastic type covering ( they don't show it in the USEI photo ) and appears the USEI has all insulated conductors and the more important aspect is that it can be had in a four wire style. As to what is to code anymore, that I don't know if USEB is ok here or not now, used to be but must be a reason why its being phased out according to the supply store.
I looked at the designation of the last power cable I had used with the aluminum armour and the three insulated aluminum conductors plus the aluminum ground wire. Its called ACWU 90 and it does state on the plastic coating that its sun resistant as per my running it down a power pole example so its suitable above or below ground, not saying others are not but most definitely if USEB is used there are stipulations on how low to the ground level the wire cable can exist without being in a ridgid conduit and so forth. Never the less I ran steel conduit from the splitter box down into the ground as it would be way to easy to damage aluminum armour cable anyway. Again, I hated handling that bare aluminum bonding wire, breath on it and it would bend over like a wet noodle as I wish it had contained a copper bonding wire.
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Post by OptimallyDismal on Mar 17, 2022 11:38:26 GMT -6
The USEI I got was 3 insulated conductors twisted with no covering 4/0, that is why I put it in the pipe!
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Post by northernfarmer on Mar 17, 2022 13:34:37 GMT -6
The USEI I got was 3 insulated conductors twisted with no covering 4/0, that is why I put it in the pipe! I think I misunderstood how they explained the USEI, it mentioned being covered in a PVC outer layer but then I realized now that its insulated first with XLPE, then each wire cable is covered again in cut resistant PVC so how strange is that. I get the impression its not designed to be buried ( unless it is with protection like you did ) . I am sure it has purposes and why its not armoured and am only speculating that probably the ACWU is probably the better or at least easier choice to bury as is as its rated for that off the roll. Having said that, I tried using as small as an elbow as I could ... forgot what they call those items that is a 90 degree head with a cover on it to come off the steel or plastic conduit to enter into a building. The armour made it impossible to work with and I had to cut the armour and pull the armour a bit to create an insulated only wire situation to make the bends, then the rest of the cable was armoured from the point of entry over to the breaker box. In the past using USEB I used a monstrous looking diameter flex armour to slide over it once it entered the interior of the wall of the building to feed into the breaker box. That is the problem with armour wire, can't make the bends to go fairly sharply around a corner. I expect the 4/0 wire was fun to work with, I've been using 2/0 for the projects I did. A neighbour had used 4/0 copper he bought cheap at Ritchie Bros some years ago on a spool and I guess that was something else, the weight of the cable just to put it into the trench and then bending each insulated cable on its own required a bender, that is the downfall of larger copper as its too stiff to work with in the larger sizes, never mind that normally it would be the price of gold. This link explains some of the properties of the two aluminum cable styles.
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Post by OptimallyDismal on Mar 17, 2022 14:32:38 GMT -6
USEI is for direct burial, I just didn't want to do that without protection, but I have seen lots go in without!
The 90 degree fitting could be an LB.
Ya 4/0 is a treat to work with all right, 500MCM is even less of a treat, that is for a 400A service, which may come my way some day soon!
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Post by northernfarmer on Mar 17, 2022 16:18:05 GMT -6
If USEI is ok for underground, I can see it has its place due to no armour on it as per fitting through the LB ( yes you were right in what I had forgotten what they were called, Line Box ) . I am sure the USEB does not take kindly to sharp rocks, nether would ACWU when it comes right down to it as all it is, is soft aluminum and no protection inside like the Tech 90 has. I think its recommended in some underground installs to us a different backfill if it its not a typical clay but instead sharp rocks, laying in a layer of clay or sand and then setting treated boards in if deemed necessary , then adding the remainder of the fill that came out in the first place. Oh and only the last project did I use "danger tape", no idea how many years that has been in effect but no such thing would have been used in this yard until the last go around.
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Post by kenmb on Mar 19, 2022 10:14:18 GMT -6
I don't know if it is code but is recommended that the usei I put in a couple of years ago was all bedded into sand. I seem to find lots of it here now after building my house and thinking I hit a rare pocket of sand. Now everywhere I dig down a few feet I seem to find sand so it is easy enough to get a few loader bucket full to place a few inches of sand in trench, drop in the cable, and a few more inches of sand on top then backfill. Going under the drive way I had some weeping tile pipe left over so threw that in there to pull the cable through. Don't know if that was a good or bad idea, only time will tell.
That armoured cable should be left with armour intact going through wall and such. Only pull the armour off to terminate at a box. To make a bend means you plan your routing to accommodate the bend. That's where cable tray or other such support structure comes into play. You wouldn't use an LB on an armoured cable. You would terminate the armoured cable at a box using a connector then add a new cable type or method to carry your feed on from there.
500MCM is kind of where I would draw the line for designing and installing. Can still form it without special tools or pipe benders. Worked a little bit with 750mcm and a rare occasion bigger but it became just a good practice to use more runs of smaller cable than spec out 750mcm or larger. Dealing with 4/0 or 250mcm is a treat compared to 500. And we are generally working with 5 & 15 KV cables thus much thicker and stiffer insulation. The point being, sometimes it is nice to run a couple smaller runs than one bigger conductor depending on what you are doing and if you can use the smaller stuff elsewhere on a project.
I haven't seen useb around the farm but that kind of design is what runs the farm with all the utilities 15kv buried cable being of that construction style - central conductor and concentric neutral with rubber jacket. A guy doesn't worry about rocks damaging it. It may happen but in my career, if an underground cable failed we never chalked it up to a rock, we would look for a buried splice that failed or simply the cable was failing due to age and moisture creeping in via damaged jacket. I suppose you could say a rock damaged that jacket but pretty much every time we inspected a failed cable it was damaged in multiple areas thus indicating a manufacturing issue or handling during installation.
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Post by northernfarmer on Mar 19, 2022 10:51:12 GMT -6
Ken, for sure that is what I was hoping I could accomplish was using an LB to make a clean install but that did not work out well as I was trying to do something that the wire was just not designed to do with that armour. I was used to working with the USEB and that was no problem in the same size of LB. The size wire I was using, the size of LB, the issue with only a 2x4 wall inside space all made for a fun install with my method. What I would have done in hindsight, not really sure actually as I wanted to avoid installing a splitter box on the outside wall of the building due to it becoming an obstruction, yet that was probably the more code sound plan to have done however the armour is on the wires within the wall so I am assuming it is to code there, I used a lot of tape around the short section I took the armour off of for mechanical protection within the LB. Oh I expect an electrical inspector may have other ideas, never had anyone look at it and seems its next to impossible anyway to get an inspector to come out to a farm, they have no interest in that. I would have had to convert over to USEI for example or maybe three insulated cables of same rated smaller diameter copper at a wall mounted splitter box and then ran that inside of flex armour in the wall. Shallow walls and wanting to remain within the wall makes it difficult, had I been using No 2 wire rather then 2/0, that would have made it far easier.
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Post by kenmb on Mar 19, 2022 11:47:28 GMT -6
I suspect the inspector will have an issue with the possibility of the armour cutting into the conductors where the cut off of the armour was made. A proper armoured cable connector prevents this. To bring that armoured cable through a wall you would pass the cable straight through the wall face then figure out how you would support it on either side of the wall. There is no proper way to run an armoured cable up the wall surface and then come through that wall. The bending radiuses of various cables in the code book have no criteria to allow such a thing. That is why, if running up the face of the wall, it would come to some kind of junction box.
Armoured cable is a bit of an unusual thing. As I recall it was developed for mines in Ontario and was accepted by local codes for use. And the use grew to be accepted and written into the Canadian Electrical Code book. And so we know it as Teck cable. However the US is still slowly adopting its use and so it is much more rare. Where as Teck90 was pretty much standard cabling in a potash mine in the 1970s for Canadian design, running cables in conduit is more a US practice. Therefore the electrical code for armoured cable is more defined in Canada vs America and perhaps elsewhere. I suspect in the last 20 years things have changed quite a bit there, but go back 20 or 30 years and armoured cable in the US code is not well known. And so I suspect is part of the reason we see why armoured cable showing up more on the farm. Not so much it is more common, but rather the code book is continuing its slow adaptation of its use in various areas. Or could be the cost vs labour calculation continues to evolve so that as labour gets more expensive to properly lay a cable, the use of armoured cable, though more expensive, perhaps has a benefit for less complex installation work.
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Post by northernfarmer on Mar 19, 2022 15:23:01 GMT -6
In all open/cut ends of the armour I used the anti short bushings and taped them in place to make sure they stayed put, then on the inside of the wall I used a 90 degree bx style connector clamp and another on the rear of the surface mounted breaker box. Again I am not saying what I did was proper or to code but did all I could to protect the insulation from the sharp edges of the armour and as well the 90 clamps are grounding the bared off ends of the armour so that from the breaker box ground running back to the LB is all grounded by the ground rod. For what its worth when I was done I didn't feel I had created a hazard with any of the wiring as I at least felt I had protected it well and the original circuits that fed out of the original box. Would I attempt that again just as I did, no. Possibly would do similar ( not claiming that would be to code either ) only a larger LB and ran up the wall further in the exact location that lined up with the rear of the breaker box hole and armour cut off as I had to back in the LB before the 90 bend, perhaps something like that may have worked and extension into the wall from the LB to protect and get rid of any sharp edges as it entered the box. Or do what I was trying to avoid and put a splitter box on the wall and connected with a bushing between the two backsides of the splitter/breaker box. I scratched my head at the time trying to figure it out as it wasn't as simple as all surface access wires due to the existing interior wall wiring, the easy part was doing the surface mount wiring I needed. When I see shops that are inside wall wired I wonder, what happens when one wants to change wiring for installs of any other unforeseen items, more lighting ..., other power requirements.
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Post by kenmb on Mar 20, 2022 12:14:51 GMT -6
I doubt you will have a problem with that cable, the inspector would flip out though i expect.
My shop is steel building with the wiring in behind the steel liner. My solution to that problem of buried wiring is to put sub panels in. Main panel is on a long panel and sub panel on each end wall. It kind of evolved that way based on how I needed to feed some things like a couple bin fans on other side of end wall. If I was to do it again I would make a couple sub panels as the backbone of the system. Then you can run surface wiring from sub panels in the future, 240v plugs are easily added and a 25' extension cord gives good coverage to wherever I roll the welding cart.
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Post by northernfarmer on Mar 20, 2022 14:16:16 GMT -6
I bet I would have to kidnap an inspector in the middle of the night to ever have an inspector come onto this yard. Years ago when I did the aeration panel(s) wiring and wire burial etc I called the inspectors office and asked him a couple of questions and I could tell then that while he answered my questions as to a certain aspect of my project and the very fact I had called at all gave him the confidence I would do a decent job and that I said it would take a while to do the various stages of it, there was extremely little interest in seeing it. I think it came down to if it was a house or a major shop build, otherwise there was little chance they would be coming out in my life time.
Ken, that makes a lot of sense with a sizable building to take that step from one central panel and do what made sense wiring behind the wall and setting up sub panels, then after the inner wall sheeting is in place any future wiring would be done surface mount to panels already in place waiting to add circuits onto. I imagine over the years you have been in industrial buildings that had wiring that was far from ideal in its planned layout and then others that were far more well laid out and not the long runs of wire that were marginal in the amount of voltage loss they would suffer from.
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