Compost

The old compost pile got full in a big hurry. It took about a month! I did have 2 big trash cans full of food scraps ready to go in on day 1, though.

Yesterday we built a new one. It's wire mesh fencing that we had from another project. A thick layer of straw goes on the bottom to provide extra carbon and catch liquid - we used a whole bale here.

The new pile has about twice the volume of the previous one. I hope it will last more than twice as long, as the compost should shrink over time as it loses water. But considering my plan to let it sit for a whole year, I'm going to end up with quite a few compost piles.

Now I just need a way to get out.

Yurt raising, continued

The plan was to put up walls on day 2. There was light rain in the morning, and I didn't want to trap any moisture in the wall layers. So we told our helpful friends not to come, and spent the day running errands.

By the late afternoon it had dried out, so Julie & I decided to go at the walls ourselves.

While the roof has 3 layers (a thin, white liner, a foil-faced bubble-wrap of insulation, and a heavy canvas cover), the walls are in two layers. The outer layer is the same heavy canvas as the roof. The inner layer is foil-faced bubble-wrap, with a piece of white liner sewn on one side. 

The outer canvas is in two pieces: a large one around 70' long that covers 3/4s of the perimeter; a small one around 23' long that covers the other 1/4. The two doors sit at 6 o'clock and 3 o'clock. Get it? There are cutouts for windows, with sewn-in fly screens, a clear vinyl window held by velcro, and a heavy roll-down outer cover. 

The inner insulation comes in pieces. There are 5 identical window pieces + 7 panels of varying length. It's a puzzle to figure out which insulation piece goes where. A new yurt comes with these details, but we don't have them. We do have this key attached to one of the insulation panels:

The instructions say to hang up the insulation panels first, loosely. Then install the outer canvas cover, and cinch it down just right. Then go back and align the panels and zip-tie them in to place. This is wrong. It's easier to put the canvas on first. You can slide the insulation in from underneath next, aligning it with the canvas that is already in the right place. We didn't know this, so we attached the insulation according to the instructions. The result looks like a classic UFO:

We did get a little help with the larger canvas wall, because it's heavy and there was lot of tedious ladder work on the uneven ground there.  Once we got it up that was enough for the day; making it snug will come later:

Yurt raising: day 1

Here are some pics from a day of yurt raising:

Getting the top canvas cover on was the hardest part, as expected. It's big, heavy, and unwieldy. We passed it up through the hole in the roof, and the spread it out and wrestled it in to place. It went smoothly thanks to many hands.

Today it's a little rainy so we're going to wait to put on the walls.

Frost-free hydrants

While we had the trenches open for electricity, we also put in water lines. Now, next to each subpanel there is a "frost-free yard hydrant." It looks like this:

The drain rock catches lost water without it making a mess. You can set a bucket on the rock, or hang the bucket from the hydrant.

When you turn off the water, a valve at the bottom opens and drains the vertical pipe underground. This prevents damage from freezing in the winter.

Underground, the water pipe is connected to the hydrant with brass fittings. Apparently many installers use plastic fittings, which snap when you attach a hose and tug. Also, a metal fence post reinforces the hydrant.

Wiring a second subpanel

Previously I wired up a subpanel to supply power to the septic system. As long as we had the heavy equipment on site, I wanted to bring utilities to the yurt/RV site, too.

The plan was similar: 2" conduit from the main panel to a subpanel on a 6" x 6" pressure treated post by the yurt. A receptacle on the post.

Last time I used 2-2-2 aluminum feeder wire, which was rejected because it lacked a ground wire. This time I knew better, so I went for 2-2-2-4 aluminum. I went to Home Depot on Father's Day. I wanted to buy the wire in the morning, and bring my family out to install the subpanel in the afternoon. I figured it'd be fast since we'd done this before. At Home Depot it took a long time to find someone to help me with wire, and then he said I'd have to wait 2 hours while they got it down from the high shelf, measured, cut, etc. I didn't get home until 6pm. We decided to postpone Father's Day until Monday.

The wire was on a fresh 500' spool. I bought 240' (11 sticks of 20' conduit in the ground + 5' riser at each end + 10' extra, just in case). They measured 260' off the spool and gave me the rest. I think they should sell me the entire spool, and refund me what I don't use. It would save them the hassle of measuring & coiling 260' of wire, the spool is useful when running the wire, and I could avoid buying the extra.

As before, we used the Shop Vac to suck a mason's line through the conduit. We used that to pull a 1/4" nylon rope. My rope was only 230' long, and so it wasn't quite long enough. That's OK, we'll just start the pull with the mason's line (when it's easy) and then do the rest with the larger rope. Just when we were about to pull the wire, I lost the little bit of mason's line. We had to pull out the yellow rope, untangle the mason's line, and vacuum it through again, and pull in the yellow rope again.

We discovered we could communicate by talking through the conduit. That was pretty fun. Worked better than yelling through the woods, too.

240' of 2-2-2-4 Al wire on a big spool is pretty heavy. To unwind it, we put a stick of conduit through the middle and propped it up on a step ladder. The wire is so stiff that it's a job just to pull it off the spool. It's another job to push the wire bundle in to the conduit at one and, and 3rd job to pull the rope at the other end.

When I wired the first subpanel, I tapped the main panel with a 60A breaker. (Remember that my plan was 30A, but #2 wire will only fit in a 60A breaker. Fine). Well, the main panel has a restriction that the largest breaker allowed on the left side, with aluminum wire, is 50A. So the breaker goes on the right.

The panel only has 4 full-sized slots, two on each side, so that limited my options for tapping for the second subpanel:

• Splice the feeder down (in the panel) to smaller gauge copper. Since voltage drop and conductor cost are unimportant over this short distance, you can use minimum-sized copper (#8 for 50A, for example, much easier to bend) and it will fit in a smaller breaker.

• Crimp on a reducing pin adapter. These require a special crimping tool, which isn't useful for much else.

• Tap the feed-through lugs. You don't get a dedicated breaker, you just attach the feeders directly to the bottom of the main panel.
  
  
  
  There's a special rule that a subpanel's feeder wires can be protected by a breaker at either end - at the main panel or at the subpanel. (Or both, which can be convenient). The nice thing about protecting at the subpanel is that you don't have to walk to the main panel to shut off the sub. 

I selected the last option.

Some panels can take a main breaker, but the only outdoor-rated main breaker panel at Home Depot was enormous - 20 spaces - and I knew I didn't need that much. I went with the same 8-space panel I used for the septic subpanel, and added a backfed main breaker. This means a regular breaker in a regular slot, but the power is going through it backwards - from the wires *into* the panel, not the other way.

The main annoyance with a backfed breaker is that you have to attach a special retainer clip to the breaker, so a future electrician doesn't pull the breaker and assume that it's dead. I bought a backfed breaker retainer clip when I was at Home Depot, but apparently I bought the MBR2 and this panel needed an MBR1. Doh.

It's just a little bit of plastic, nothing complicated or expensive. But neither local hardware store had one. Double D Electric, an electrician with a retail operation, had a box full of MBR2, and an empty box labeled MBR1. Damn.

I had them special order the MBR1 and finished the rest of the wiring while I waited. There are receptacles in a weatherproof box on the post - this time I used a double-gang box so I could have 4 total outlets.

Ground rods in the ditch - the ground was very hard so they barely moved under the force of the rotohammer. They just made it in the first foot, and then I bent them over.

Neutral 3 lug kits - one for each end of the ground wire + one for the neutral wire at the main panel.

Because the wire is long and expensive, I wanted to cut it long. Suppose I screw up & need to cut the end off? Or I want to move the panel a short distance? At the main panel end, I put in a loop.

At the subpanel end there's not enough room for a loop, so I sent the wire on a long journey in the panel. It comes in at the bottom, turns right, then up the right side, across the top, down the left 1/2-way, and in to the breaker.

Finally the hold-down clip arrived at 2pm. The cutoff for requesting an electrical inspection is 4pm. I wanted to get the job 100% done before calling, in case something needed more work. Picked it up from the shop, headed out to the site, and spent 15 minutes trying to figure out which end was up. I snaps in to the bottom of the breaker in a specific way. Then you install the breaker in the panel and the clip snaps it a special slot. Turns out this slot is on the *right* side of the panel, and I had installed the breaker on the left. Time to re-route the feeder wire. This #2 stuff is hard to bend, and I had too much of it (on purpose). I wrestled it in to a new shape, going up the right, then down the right, then back up the right in to the breaker. It's a bit crowded in there, but it works. It was still before 4pm, so I called in the inspection.

The only work left was to label the panel's front plate and remove the knockouts for the breakers. I had waited to do this until the retainer clip was installed because I knew there was a chance I'd need to move the breakers around, and I wanted to avoid popping out the wrong knockouts. Good thing, since I had to move the breaker just as I'd feared.

I carefully oriented the front panel correctly, picked the right knockouts, and removed them. Then I put the panel on the breaker box and discovered that I had it backwards. Wrong knockouts. This is why I keep filler plates on hand.

I never saw the inspector, but the next time I looked at the panel, there was a sticker and the permit had notes of approval on it. Yes! I'm done wiring for a while.

Septic system squirt test

A few days ago they did the "squirt test" on the septic system:



We have clay-rich soils, which water has a hard time seeping through. To compensate, the trenches are first excavated to 4', then backfilled with washed sand to 2'. The drain lines are embedded in a couple inches of drain rock. A layer of landscape fabric above that keeps out fine dirt. Then the top of filled with the spoils of excavation, back to grade.

Because our soil percolates so poorly, the drain field is oversized - double the size for good soil. This way, the soil gets 1/2 as much effluent. A problem with a very large drain field is getting water through the pipes all the way to the end. A small flow of effluent would exit the pipes near the beginning, leaving the end of the drain field dry. To make the whole drain field operate, the system waits until there's enough effluent in a holding tank, and then squirts a predetermined dose in to the drain field with a strong pump. The system is programmed not to exceed the absorbtion capacity of the soil. If you produce a lot of wastewater in a short time, it will fill the tanks and trigger the alarm, but it won't overload the drain field.

We have 6 trenches, each 50' long, for a total of 60' of drain line. There's a manifold that distributes the effluent to the 6 trenches. The manifold has adjustment valves to ensure that the effluent is evenly distributed throughout the drainfield. In the video, the designer activate the pump and observed that the water squirted to the same height across the whole drain field.

The original septic design was for a 5-bedroom system, which required a much bigger drain field. That's too big to pump to the extremities, so the design used a "ratcheting valve". This split the drain field in half, alternating the doses. Because we downsized to a 3-bedroom system, we got to skip the ratcheting valve, but we needed a bigger pump - 1.5hp, 240V 15A, hence the big wiring operation.

They did a "drawdown test" as well. They measured the height of the water in the pump's holding tank, turned on the pump for a set period, then measured again. From this they calculated that the pump can squirt out 100 gallons per minute - wow! Based on the desired size of a dose, the figured that the pump should run for 27 seconds each time. There's a minimum of 4 hours between cycles, so that's about 3 minutes per day, tops. All that wiring for 3 minutes per day?

After the test was complete, the designer and his assistant mapped out the locations of the trenches and inspection ports, which they'll draw up back at the office (for a fee). Then the builder finished filling the trenches and grading the soil. The septic system is done.

The health department will do another inspection before giving the final approval.

How to build a yurt platform - part 10

Today we:

- installed all the foam insulation panels
- attached the perimeter blocking
- installed all the yurt decking

In progress:

Installing the last piece:



Done.

That's straw on the ground, because it was muddy today.

Next:

- Attaching the plywood drip edge
- Sand and paint the deck
- Possibly install an electric subpanel on the post visible in the above picture, to make power available for the saw & sander.