We had some serious bonding today, with Akeena Solar and Clausen Electric, Inc. working together to ensure our complete electrical system and house was bonded correctly.  And thoroughly.

Bonding

According to Wikipedia,

Electrical bonding is the practice of intentionally electrically connecting all metallic non-current carrying items in a room or building as protection from electric shock. If a failure of electrical insulation occurs, all metal objects in the room will have the same electrical potential, so that an occupant of the room cannot touch two objects with significantly different potentials. Even if the connection to a distant earth ground is lost, the occupant will be protected from dangerous potential differences.

After reviewing the alternatives, they concluded that we will run rigid (metal) conduit coming from the roof in the 20 ft interior concrete wall to a metal junction box.  The metal junction box will be accessible from the crawl space under the raised pantry floor.  The metal junction box will carry a ground wire to the junction box in the Mechanical East room, which is where the inverters are located.  Thus, the entire solar system will be bonded to the house.

'It's all good,' says Will Shippee (right) of Akeena Solar (Ron Ivancich of Clausen Electric on left).

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Shooting the shotcrete test panel and three compression test samples took 12 minutes to complete.

Preparation

Setting up the test took less than 30 minutes.  

Test panel is in position so it will be easy to shotcrete (and can stay in this location for several days).

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Importantly, the surveyors scored offset marks in each of the four corners of the existing structure in the structural slab.  These offset marks will be used to ensure the new concrete retaining walls below grade are in the correct location and are perfectly square.  We need to have concrete retaining walls that are square so the interior walls are also square.

Offset in south-west corner of the house by 3'10".

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These concrete walls need to be strong and heavy.

We need concrete retaining walls around the perimeter of the house as well as interior structural concrete walls.  These walls must support the weight of the house (point loads) as well as provide shear strength.  Importantly, these walls must contribute to the 1.5 million pounds of dead weight that we require to offset the hydrostatic pressure (so our house doesn’t float).

Where are we going with this?  Yes Scott, you are correct – more rebar.

Placing rebar in the north-west part of the perimeter retaining wall.

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We hosted a visit by the Weblos (Grade 4 Cub Scouts) from Pack 371 today to help them earn their Engineering badges.

Our son, Nikolas, is a Weblos I in Pack 371 and we hosted a visit by his Den to our construction site so they could learn about engineering.  Mike Calise, a good friend who has a daughter a few months older than Nik, put together a Powerpoint presentation on engineering as a career, and then walked through the presentation at the construciton site with the boys.  His inspiring presentation introduced what engineers do and what their careers can include.

Mike Calise introducing and explaining a career as an engineer to Pack 371's Weblos Den. Mike had a great Powerpoint presentation to inspire the Weblos to become engineers - thank you Mike!

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One of the three houses in the San Francisco Bay Area that is current pursuing LEED for Homes Platinum certification is the Christensen Pierret Family house, located at 2180 Bryant Street in Palo Alto.

Sign in front of 2180 Bryant Street in Palo Alto, listing the pursuit of LEED for Homes Platinum certification and the design team members.

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