Ditto what Phil and Bill said. Also, I've found that you must add a
few sizes larger on the diameter of the hole as the straw tends to
fill the gap as it's drilled. On a recent job we had to utilize a 2"
hole for 1.25" conduit and it still needed to be forced a bit.
Downward slope is great advice too. Luckily my customer did that by
mistake.
Have fun, Nick
On Nov 19, 2010, at 12:22 PM, Phil Undercuffler wrote:
Having a fair bit of experience with bale, I ditto what Bill
mentioned but I'll add a simple way that I discovered to getting
the inside and outside holes to line up.
Bale walls are seriously thick, so standard extension bits aren't
long enough. I found taking a 2 or foot length of 3/8" rebar
chucked into a half inch drill works nicely for boring a pilot hole
all the way through the wall. Once you have the pilot hole, it's a
simple matter of drilling out a hole large enough for your conduit
on both sides of the wall. Either use a small bit to drill a
series of holes around the perimeter and connect the dots with a
cold chisel, or use a hole saw that you don't mind sacrificing on
the plaster. You don't actually have to "drill" through the entire
wall, as the straw can be pushed to the side. I usually spin the
rebar in the hole while chunking it back and forth a few times to
clear a path, then thread the conduit through the hole using the
rebar as a guide to be able to find the hole on the other side. It
really helps to have a second person on the other side, to help
guide it in the final inches.
Rebar as a drill bit also works great with adobe walls.
If you do a lot of this, take a minute to grind down a flat spot on
the end of the bar or it will tear up your drill chuck. Drill
chucks can be spendy. Ask me how I know...
Phil Undercuffler
On Fri, Nov 19, 2010 at 11:27 AM, Bill Hoffer <suneng...@gmail.com>
wrote:
Benn
I used PVC in the my bale walls with a Junction Box on both sides
of the penetration to protect the penetration (Outside a must!).
I used EMT for all my other wiring, but PVC seems better for an
interior to exterior penetration where the heat conduction of the
EMT may cause some damaging condensation towards the exterior of
the bales. I used a hammer drill and concrete bits to get through
my stucco, it is tough stuff. I used 2 " conduit so I had to make
several smaller holes and knock it out by hand. I did not have
rebar in my bales, but heavyduty 6x6 mesh to get through, as would
be expected I never was able to hit the middle of the grid, I just
had to cut and hack saw when I hit something, pays to have a
sacrificial bit to find the metal. I then fashioned a home made
bit out of the conduit and used that to get through the bales by
hand. That went pretty easy and will allow you to locate the rebar
without damaging an expensive bit . Hard part is lining up to get
a good mark on the opposite side. I used foam to fill any gaps,
replastered around the pipe and fitting and caulked really well to
seal against water on the outside. I also located the JB on the
outside of the building in a very protected area for additional
security. Water and straw bales do not play well together! If
anything I would favor a slight slope downward on the outside so if
there is a leak it will not follow the pipe inward into the bales.
Hope that helps!
Bill
On Fri, Nov 19, 2010 at 11:05 AM, benn kilburn
<b...@daystarsolar.ca> wrote:
Wrenches,
Short of contacting the builder, i'm looking for your experiences,
practices and "look-out's" for penetrating a strawbale exterior
wall with conduit.
For the project in question there is currently a teck cable from a
wind gen entering the home by sharing a HRV vent opening that i
want to fix (not my original system by the way) and i will also be
adding another penetration for a PV array that i am relocating on
the property. The original penetration for the PV was done properly
but its not in an ideal location for the re-located array wiring.
I'm wondering if it is as simple as using a hole saw extension to
go thru the ~16" wall and use an LB/box on either side. I'm sure
there is some framework and/or rebar supporting the bales, how do
you locate/avoid these when there are no corners to measure from?
(it is a round home)
Any knowledge if PVC or EMT will react in anyway with the bales?
I'm thinking that PVC would be best....?
... i am trying to contact the builder to address this, and also to
ask a few choice questions regarding the wiring methods (he?) used
in the original PV system set-up.
Cheers,
benn
DayStar Renewable Energy Inc.
b...@daystarsolar.ca
780-906-7807
HAVE A SUNNY DAY
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Bill Hoffer PE
Sunergy Engineering Services PLLC
2504 Columbia Ave NW
East Wenatchee WA 98802-3941
suneng...@gmail.com (509)470-7762
Cell(509)679-6165
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