“Nearly all men can stand adversity, but if you want to test a man’s character, give him power.” – Abraham Lincoln.
“Never underestimate the power of stupidity” – Robert Heinlein
OK, so maybe those quotes don’t have much to do with hooking up my main breaker, but I wanted power, even if it tested my character, and I was not too stupid to get it ;^)
In my region, the power company has set things up to favor a proper service entrance setup rather than temporary “construction” power. The temporary setups have more paperwork and lots of rules about the setup, such as you can’t have outlets more than 10 ft from the transformer. They also make it more expensive than hooking up the actual house main power. On the phone with the power company, and I said, “With all this hassle and expense, why would anyone want to get a construction hookup?” and they guy on the other end just said, “Exactly.”
Of course, I had no wall to mount the electric meter or breaker on, so I would need to continue with my generator for a while longer. I appreciated having my generator, but I didn’t like the noise and I really don’t want to make things noisy for my neighbors. I also don’t like paying for gasoline. Getting electricity on site just makes the whole building process easier.
Once, when I stayed past sunset the night before a pour day, a neighbor drove by and told me to, “Go home.” All I could do was reply, “I’m working on it.” I shut the generator and lights down within 15 minutes and finished up the column forms by flash light.
This post is just the story of how I got that power hooked up. If you know anything about electrical, my mistakes will be obvious to you, no need to point them out now. Anyway, I learned a few things along the way to getting it right and ended up still saving a lot of money.
Why do it myself?
The quotes to get my electrical done were not affordable. I tried to get other quotes, but most electricians never got back to me or told me they were not interested in bidding for such an unusual home. The few that did get back to me wanted more than $64,000. I asked one of them about the crazy price and he said it was about triple his normal rate per square foot because he still needed to figure out how to do it. Some of this was because I have electric backup heat and electric hot water (on demand), which increased the overall power requirements, but most of it was just because the house was not like anything they had ever done and they had to estimate high to cover their risk (understandable).
I have already wired the basement, and that only cost about $400. I was already pretty familiar with that sort of basic wiring, and you can find tons of information in books and online, so it was no problem. Taking care of the service entrance and main breaker was the next step. However, it was something I was unfamiliar with and most books on wiring don’t cover beyond a basic hookup.
Why those two big switches?
My house is long and the service entrance was at the far corner of the garage (closest point to the transformer). If I ran all the circuits from that back corner of the garage, it would be a huge task to wire the house, with many of the runs going well over 150 ft. It would be a wire-pull nightmare. Also, the cost of all that wire, especially the bigger stuff for the on demand hot water heaters, well pump, etc. would really start to add up. The concrete walls and unusual shape would also make it tricky to run circuits between the various sections.
So, I decided to put a breaker in each major section of the house. I figured one in the in the laundry room, for the bedroom wing, and one in the mechanical room (under the middle of the house), to cover the rest of it. However, the total AMPs required between these breaker panels was also going to be well over 200, so I couldn’t just have a main breaker and a sub breaker.
Code requires that the power from the meter socket should not travel very far before it passes thru a breaker or disconnect. If I was not going to have the Main Breaker right on the other side of the wall from the meter, I would need a fusible disconnect switch to turn off the power in case of a short. You can get reasonably priced switches for 30 amp or even 100 amp circuits, but they get big and expensive for 200 amp circuits. My 200 AMP fusible disconnects are pretty much considered “commercial” equipment and I had to special order them.
There was also the issue of scheduling. I had the back wall of the garage up well before I could put up either of the other panels. The wall of the laundry room won’t even exist until June 2016 (or so). Having the switches lets us hook up the main power now, but just leave the switch off until I have the panel installed. This is why the disconnect on the left is not connected to anything.
The breaker panel to the right of those big switches was originally a temporary idea so I could have power during the build. I planned to move that one to the Laundry room eventually. However, I have since decided to replace it with a smaller panel and just wire the garage circuits from there instead of from the mechanical room. This will save me time and money and lets me get the garage circuits going sooner.
Building codes are important, but the code is not always clear and there is a learning curve when applying book knowledge to the real world.
I had passed my basement wiring inspection easily, but the service entrance was more mysterious. What info I could find in books or online really only covered the basic situation where the meter and main breaker are just inches apart. From reading the code, I knew I would need to add switches, but I couldn’t find out much about how to install them, etc. I hoped those expensive switches would at least come with some instructions, but they didn’t. I figured I could figure it out well enough.
Some of the mistakes were things that I had known earlier in my life, but temporarily forgot or just messed up in the rush to beat the ground freeze.
Oh well, mistakes were made and that is what in the inspection process is for. I will try not to mess up like that again, but, for now, I am moving on, still happy that I saved many thousands of dollars over getting a pro to do it. I also learned a bit more than I would have otherwise.
Turning on the power
On the first day, two trucks and 5 guys from the power company showed up. I had booked the day off work to be there and was anxious for them to get started… They didn’t. Only one guy even got out of the truck to talk to us. We asked what the delay was and he said they were a bit confused about where to run the cable. Basically, they wanted to run from a slightly closer (180 ft distance box), even though it would require digging across the driveway, which they did not have the equipment for anyway. I had already got the power company to agree to a 15 ft longer path from another transformer that would stay far away from the drive way or any thing else and only cut thru soft sand. Anyway, they didn’t want to start until the project manager at the power company approved what I told them he had said. He wasn’t in that day, so they would just wait.
I thought that was crazy to just sit around all day, but they told me not to worry because “This has been spec’ed as a two day job.” He basically made it clear that I didn’t need to worry about how long they took because the cost was fixed. They stayed, sitting in their trucks, all day, but did literally nothing towards hooking up my power. I was pretty annoyed that I would need to take a second day off work, but at least the weather was good and I was able to work on other things.
The next day, they were back before 9:00 AM. They sat in their trucks for the first hour or so. We went down to ask them if everything was OK, but they just said they would get to us soon. Eventually, a few of them came up and looked at the meter cabinet while a couple others got the trenching machine off the trailer.
During about a half hour time frame, they hand dug the first couple feet by the wall/foundation and then used the excavator arm to dig a short trench, maybe 20 ft long. This was done by 10:22 AM.
They said something about not having any 3 inch pipe with them and said they would need to wait while someone brought some. This is the standard pipe that they always use, so I thought it was funny that they hadn’t brought any with them. However, they only needed a few feet of it and I had several pieces laying around. I offered them a piece, but they said they would just wait for the delivery. They waited in their trucks until 11:40.
The next step was to use the trencher to lay the cable. One guy drove the machine and another fed the wire into it by hand. The wire was pulled down thru a plow that split the earth to lay the wire and then let the earth close up behind it. It basically moved at walking speed, so the cable was laid within 15 minutes. The cable had been laid on the ground next to the path before hand, so the whole process looked similar to pulling up a zipper. Then they took a 20 minute break before the one guy came back up with the machine and filled in the trench at the top at 12:21. Again, that was just a few minutes of work.
They put the machine back on the trailer and were quiet again until 1:54 when some other guys came out to hook up the meter socket (meanwhile the trencher guys stayed sitting in their truck).
Here I should note that, other than something to cut the cable, the only tool these guys need to attach the cable to the meter socket is a 3/8ths inch Allan key. This is the same sized Allan key they need for every single service entrance job that they do. Guess which tool they didn’t have? I loaned them mine.
Roughly 20 minutes later, they were done. hooking up the 3 wires. After packing up, one guy came to tell me that I could start to use the power. That first attempt video was shot right after they left at 2:22 PM. That didn’t work. Obviously, I was pretty annoyed with the crew by that point. I called the power company and was told someone else was planning to come and finish the setup.
After my family had gone home for dinner, a sixth guy showed up around 6:20. He did something to start my meter (I didn’t see exactly what he did, but it was quick.) It seemed to me that perhaps I had misunderstood the first crew and the power was not supposed to be on until this guy came and did his part? I asked him about it, but he didn’t seem to understand my question. He quickly sealed the meter box and told me I could start using the power, and then he was on his way. I filmed that second video, with working electricity at 6:26.
So, let’s do the math. They were at my site for most of two days, but my time-stamped time-lapse pictures show that parts of the crew worked on my hookup for less than an hour and a half. I guessed three hours in the video, but I see that was much too generous. If they were doing something in that truck, I can’t imagine what. Keep in mind that this is a private company, not even government work. But they do have a monopoly in the region, so maybe that explains it.
The 2/0 cable was about $1.50 per foot and I needed 3 cables, each 15 ft long, so 65$. There was also the 45$ worth from my first try that was wasted. The ground wire was about 10$, plus 25$ for the two grounding rods and acorn clamps. The main panel (200 AMP QO) was about 200$ and the 20 amp breaker I installed for the construction circuit was $7. Those big switches (200 amp fusible disconnects) were very expensive at over 330$ each, and each took 30$ worth of big fuses. There was maybe 20$ worth of 2 inch conduit. Then there were a few small things like Tapcon screws to mount the boxes, etc. I had them already laying around, but lets say 5$ for all that.
So the hardware total is, $372 for the service entrance and main breaker, and $720 for the switches, so $1092 total.
The price to get the power hooked up was reasonable… 820$ up front covered the meter box and all the hookup, including the 195 ft of cable from the transformer. Since it took 5 guys a couple days to get it done, I am guessing it cost the company more than that to do the work, but they plan to get the rest from me over a lifetime of electric bills.
It was going to cost an additional 3$/ft if the ground froze (nearly 900$ more). So, after getting the back wall completed in october, I was in a rush to get the service entrance installed and inspected and the hookup scheduled. That rush may have contributed to the mistakes. It was only due to the merciful “Al Gore” winter that let me delay into the middle of November without the ground freezing.
So total to get the service entrance and switches up and running is ~$1910. A big chunk of my electrical budget, but only a tiny fraction of what the professionals would have charged. Of course, there were also a few evenings worth of time to get it done and then rip it out and do it again properly.
The core of my unusual earth sheltered design includes 10 precast concrete ribs. I did try to get these done professionally and asked 4 concrete casting companies for quotes, only two got back to me and the average was about $80,000, plus shipping. I asked what they planned to make the forms out of, and both companies said, “plywood”.
Since each of the 10 ribs only includes a few hundred dollars worth of materials and the forms are also relatively cheap to make, I decided to try it myself.
It was definitely more work than I expected, but I was able to keep the cost well below even my estimate by using a lot of the junk wood left over from forming the footings. I think the cost for both forms was less than $300, and then I put in about $200 worth of rebar and 220$ worth of concrete into each. That is less than one 10th the cost of having it done professionally.
The rebar cage was inspected before the pour (you can see the inspectors feet at one point in the video), and passed.
I think the first two ribs turned out well, and there were already some lessons learned, but I will make a few more before I add “Lessons Learned” to my Precast Concrete page.
In the mean time,
Here is the video;
And here is the story;
I like to include this text because it makes it “searchable”. I also try to provide more info than I can provide talking thru the video.
If we get rid of all this peripheral stuff, at the core of this design are radial vaults around a central tower. I need the load from the earth above the vaults to be carried to the footings. I also wanted to keep the vaults small while allowing an open concept living space between them. My solution was to support the vaults with these Euclidean-egg shaped concrete ribs. I chose this shape, with its continuous curve, because of its compressive strength and drawability. The inside end of these ribs will sit on this steel compression ring that will help distribute the load to the tower and steel posts and ultimately into the footings. The egg is tilted so that there is lots of head room near the tower where doorways need to be placed. On the outer edge, an integral column carries the loads directly into large 4’x4′ footing pads.
Eventually, I will span these ribs with steel arches that will form the shape of the vaults and hold up the metal lath that will catch the shotcrete, but I am getting ahead of myself…
First, I need to cast these ribs.
I worked out the forming details in 3D, and it was well worth doing even though I didn’t stick to the plan exactly. The original plan was to layout the wooden forms on a plywood base in the garage (this didn’t quite work out as planned). I used shelf brackets and thin plywood to build the sides of the forms. In the orginal plan, I imagined using 1/4 inch plywood, but In the end, I used multiple layers of 7mm lauan underlayment and a final layer of white board.
The specific rebar layout was designed by my engineer. I really think it is probably “over designed” and working with that #5 rebar is a pain in the butt, but considering how important the strength of these are, I wasn’t going to short it… In fact, based on my own calculations, I actually added additional rebar in the the one place where I felt the engineer had not gone overboard enough… I put an extra two 20ft pieces of #4 rebar along the central spine and belly of the arch. I also integrated 3/8ths inch steel bearing plates at the high end of the arch.
The concrete volume is about 35 cubic feet, which, at about 150lbs per cubic foot, puts the weight of the arch at around 5000 lbs. Maybe the crane operator can tell me the exact weight later.
For practice, I also made a quarter scale model a couple years ago, and practiced drawing out the full scale arch on my driveway.
But this year, it was time to try the real thing. I laid out cheap particle board sheets, screwed them together, coated them with waterproofing and began to construct my curves. This is really a scaled up version of the techniques that old-time graphic designers used to create fonts with tangential curves (before they had computers). The key to tangency is that when two arcs meet, the radial lines where the arcs meet must pass thru the center of both.
Then it was time to cut boards to fit the profile of the arch. This involved tracing them on the floor, then cutting them with a band saw and sanding them. The curves from the band-saw were are not perfect, but I sanded off the main problems and the successive layers should smooth things out.
Then I realized that my particle-wood-base idea was not going to work… humidity and temperature changes during the day just caused too much warping and movement. The waterproofing had been a waste of money and may actually have contributed to the problem because the edges were absorbing moisture and swelling differently to the rest of the boards and this led to curling. Hopefully I can reuse these waterproof boards somewhere else later.
Before removing them, I drilled thru to mark the key centers of the arcs on the floor, then I came back and drilled larger/deeper holes that could hold a nail and work as pivot points so I could quickly reform my egg-arch shapes without redoing the whole Euclidean process.
Then it was time to build up the sides of the forms… I used shelving brackets as planned. Each is supposed to be able to hold 250 lbs. I spaced them less than a ft apart. Even if they had to carry the full weight of the concrete laterally, they should have strength left over. I had to back them with some plywood blocks (not considered in the original design) so my other layers could attach to something.
I needed to make sure that the forms could be easily taken apart. I didn’t want any shifting at the joints, so I used a series of 4 inch offsets with the layers of thin plywood… Where these “separable” layers overlapped, I had to be careful not to glue or screw. Instead, I relied on notched pieces of 2×4 to keep the overlap closed tightly until the lateral load of the concrete was in place to keep it tight. Then I would remove the pegs. (In the video, these were sticking up from the form with yellow tips)
Since I didn’t have the wood base anymore, I eventually needed to attach these form segments directly to the concrete slab with tapcon screws.
The forms for the spandrels (those cut out holes in the ribs) were a bit trickier. I made the series of parts for them with a very carefully planned process of angled passes thru the table saw and router… Then I nailed them all together with my air gun. I had included a fairly significant draft angle so I could get them out of the concrete at the end. This made skinning them with the last white layer a bit more difficult and I had to trim to fit.
I had a similar problem with the tighter curve portion of the rib… I guess my form walls were not perfectly vertical and I had some trouble with the 3rd layer and had to trim it off. After that I used smaller pieces so the angular error didn’t add up.
Eventually, I attached the remaining form pieces to the slab and caulked all the joints… It used up three tubes of silicone.
Then my friend Dan showed up to help out… He took on the job of creating the hangers across the form. These will be used to hang the rebar skeleton so it is positioned in the middle of the concrete. There was also some thought that they might help hold the form together against the pressure of the wet concrete.
Meanwhile, I got started on the Rebar… I had ordered a pallet of pre-bent “Stirrups” and placed just the amount I would need on that pallet in the middle. These were custom ordered and delivered for not much more than the cost of straight rebar. Most places quoted me the price per lb, rather than per bend, so once you pick your supplier, it is pretty easy to estimate costs.
The majority of the rebar was the very thick “#5” rebar. It is not easy to work with, and even more difficult to curve precisely. Dan came up with this idea of clamping the pieces directly to the hangers and forming them in place… It worked very well.
The#3 rebar stirrups need to be threaded on to the long rebar peices ahead of time for easy placement.
Tying rebar is not very fun (time-lapse did not capture many smiles, and this smiling pic above was early in the process. I forget what Dan had just said). You need to bend over a lot and (because I kept not wearing gloves) my hands were pretty cut up by the end of the process… I was glad to be working in doors during all that rain though.
As we neared concrete day, another friend, Aaron, came out to help with the second rib. We used the same process to bend the long pieces and were quite a bit more efficient with this second rib, but it still took me half a day to get all the rebar in and tied.
Pouring the Concrete
Finally, Concrete day arrived. We poured the basement floor and ICF blocks first (another video), and then it was time for the ribs.
Sherri sprayed everything down with form release agent so the concrete wouldn’t stick to the floor or forms. Actually, we used a bug sprayer, but it wasn’t able to spray finely enough (it should be more like a mist) so we wasted a lot of the release agent trying to get coverage. More is not better. The heavier application of release agent was running off the whiteboard instead of coating it. I plan to buy a proper sprayer for next time.
Then the concrete pipe was brought in and things got crazy for a while.
The pipe was very heavy and stiff and generally difficult to move. The pump truck guy took pity on me and stepped in to show me how it was done… Instead of trying to lift it, he was leaning into it. It reminded me of my windsurfing days as a kid. I still never got the hang of moving the concrete pipe effectively, but we got the job done. Next time, I am hopeful that the pump truck operator can park his truck in a slightly different location so that his articulating arm can better access the forms.
We used a concrete vibrator to consolidate everything and it really helped. I had surveyed people on facebook about this and most told me not to worry about it, but these are so critical to the design, but structurally and as visual elements, that I didn’t want to skip on this part. As soon as the vibrator entered the concrete, it liquefied (like sand in an earthquake) and flowed into all the crevasses. Actually, when the vibrator touched the rebar cage, its vibrations were transferred and affected the concrete several feet away. I am glad I didn’t just try to hack it with a sawzall or something like that. I don’t think it would have had the momentum to move all that form or rebar.
The concrete was poured very quickly. I was exhausted and we took a 5 minute break for drinks, etc.
After the concrete setup for a bit, I cut the hanger wires and removed them (along with the hanger boards) and then we troweled over the surface so you don’t see any holes. My wife, Sherri, actually liked the finishing part of the job. We used buckets of water to clean the concrete off the hangers and tools. And, of-course, it was all a race against the setting concrete.
Eventually the crew that had been finishing the basement came in and help with the final edging, etc. This pic is immediately after the chaos, before the cleanup. The wires were hanging the rebar cage. This all cleaned up just fine.
Next Step… we need to take the forms off, and move the ribs out of the garage so we can reset the forms and pour 4 more times.
The skeletal steel frame of my earth sheltered house is critical to its success, and getting from the plans to hard steel on site took a lot of effort and is therefore worth a post…
I’ll probably end up putting notes about the more nitty gritty details and lessons learned into the technotes and design tips section of this site… When I am done learning.
In the meantime,
here is the video.
Steel frame basics
So, the structural design of my house is essentially Shotcrete sprayed over a steel frame skeleton. You may not see this often, but you can find many examples on line.
Check out some examples on the Formworks site (their facebook page is excellent), or the site of their brother company, PBS. I would love to know the falling out story behind that split, but it is clear that the brothers did their early work together because a number of homes are shown on both sites. After the split, the Formworks designs get pretty interesting, while the PBS designs stay pretty simple in terms of geometry.
Formworks uses 3×4 I-beams to span vaults of up to 50ft across. They weld Z-brackets on the side of the IBeams to make it easier to add the rebar later. Special brackets are bolted to the slab foundation and then the I-Beams are slipped into place and bolted to the brackets. The rebar is dropped into the z-brackets and they are hammered down to lock tight. They also have a variety of specialty hardware for bolting the IBeams together, attaching floors, etc. It is a pretty good system, aimed at helping the “do-it yourself” earth sheltered home builder be successful, and refined over many years of actually building these sorts of homes…
So, why would I try to improve on that?
Well, for starters, I didn’t really like the large flat front parapet wall design that many of these homes end up with… I guess it looks pretty good if the home is mission style, but I was wanting something that looked a little more integrated with the earth. I wanted the hard edges a bit more broken up. It is just personal taste, but I wanted something more like a single story “Hobbit home” than a 30 ft tall “Lonely Mountain” edifice. This meant that I was going to be keeping my heights and spans low. I also couldn’t resist the idea of mixing and matching in a whole bunch of different arch forms. The resulting jumble of small arches required a new approach.
My wife and I have talked a few times about how stringing together 4 Quonset huts would have saved a lot of time and money. I would be done and writing my earth sheltered book by now if we had gone that route. I actually had some pretty good ideas for how the exterior could be softened (we were going to go “modern wave”), but we couldn’t agree on a good way to finish the interior and we had already put so much thought into the other plan… But maybe a simpler plan would be a better idea for you?
My overly complicated design includes 3 groin vaults, 3 apses, 10 radial vaults (of 3 basically different sizes), a portion of a “toroidal” vault and one simple vault over the mud room. In some cases, those steel arches are sitting on precast concrete ribs or spanning shotcrete walls. It was a lot to plan out.
Square or Round tube?
Originally, I had planned a mixture of both square and round tube (based on tangency to the ceiling below), but I ended up switching to all square tube because it is stronger in its primary load direction (because there is more material where the peak stress occurs) and costs less… But I later discovered that it is harder to roll-form (without deforming or collapsing). Paradoxically, some places insisted on the steel being thicker (0.1875 instead of 0.12, or 50% heavier) so it would be easier to roll. The company I ended up with just took their time and the deformation is barely visible.
The radial vaults spanning the curved ribs were the most tricky to plan because I needed to adjust the radii of the steel arches for the location and curvature of the precast concrete ribs they were sitting on. I ended up deciding to have a level interior and used a simple formula (Rarch=2πrθ/360) for the arch radii at each location, but used the 3D model to calculate the length of the spacers between the arch section and the curved concrete ribs.
Again, in order to avoid the “flat south façade” look that too many earth sheltered homes end up with, I wanted the dirt to spill down around the bedroom windows. I decided to “miter” the corners. It seemed like I should use properly shaped steel to get that miter shape right and that required ordering “ellipse” shaped frames. This turned out to be quite a bit more difficult than the regular arches.
They basically made them by creating pieces with simple radii and then welding them together. Then they tweaked them a bit (more of an art than a science) to get them to match a full sized template that they had asked me to make. The end result cost about 3 times what I would have paid for a simple arch, so I hope the shape they give the bedrooms is worth it in the end.
To make the template, I used the two foci and a string method (shown in the video). The coolest thing I did there was make a little car out of Lego that had a place to hold the Sharpie and two pulley wheels to hold the string as it went around. This made drawing a smooth curve much easier.
When it came to quoting me for the arches, it became clear that most companies were quoting me per “roll”, regardless of the length of the roll or even the size of the steel. Since I had a number of half arches for forming my apses and the corners of the bedrooms, it was clear that I could save some money by ordering those as full arches and then cutting them in half later. I made all the drawings this way… For instance, that ellipse piece will be cut in half as a corner piece before it is installed. It is also easier to weld the legs on straight if I do it before the pieces are cut in half.
Some of the companies were strictly rolling and wanted me to do everything else myself. The one that I ended up with including the cutting in the base quote, but would charge me 50% more to weld the pieces together. Since I would still have other welding to do anyway, and because I kind of like doing it, I decided to do all of it myself (or with friends and family).
For the next few weeks, I will be focused on getting these arches welded together, and the bedroom ones in place. I am also still working on the precast rib forms and trying to get the quad deck guys to come out…