Electrical Changes at 4180 SW 99th

The following work done by homeowner Keith Lofstrom (me), and PC Electric of Newberg.

I trained in electronic engineering, and design integrated circuits. The voltages, currents, and sizes are all very much smaller, but many of the calculations are the same. I read books on home electrical work, and learned the most from "Ultimate Guide to Wiring", 6th Edition, by "Creative Homeowner". I also read large parts of the National Electrical Code, and various online resources. My goal is to do things right, and do things safe.

Many of the changes I made to old wiring are not strictly necessary, since the old stuff is grandfathered. But where I could do so without major disruption, I updated the wiring to match the current code, maximizing safety. When I added boxes, I made them bigger than necessary. I used grounded metal, insulated staples, and replaced electrical tape with wire nuts or crimp splices.

As I learned more, I improved my methods. For example, I used more crimp connectors. In a few cases, I used plastic boxes, where their water and corrosion resistant nature outweighed their lack of structural grounding.

In some cases, updating was difficult. For example, many receptacle boxes were the "half octagon" shapes with nails through them. There is no room in such boxes for GFCIs, so the whole branch got a GFCI breaker in the electrical subpanel.

The house as purchased had quite a few open boxes, some with dangling hot wires wrapped with decaying tape. Every open box we could find is either closed and wirenut-ted, or used for something new.

The changes, in detail

Electrical Subpanels

The house originally had a Federal Pacific Stab-lok breaker box with failing breakers. These are a known fire risk. The connection to the meter was a large, nonmetallic cable to the meter box, hanging loose and unanchored outside. How that passed inspection, and survived 50 years, is difficult to imagine.

Basement Lighting

The two main rooms in the basement, recreation room and shop/storage room, were poorly lit with a few bare bulbs and three T-12 magnetic ballast strips.

Other lighting

New receptacles

Miscellaneous

duty extension cord, through the access hatch, to a downstairs bedroom (AFCI) receptacle when I am working in the attic. Normally, these are completely disconnected.

Low voltage wiring

The low voltage wiring, telephone and ethernet, has been rerouted down separate plastic cable channel.

Paneling and wiring protection

The Oregon structural code has not yet caught up with new knowledge about seismic risk, though engineers and professors from Oregon State and University of Washington are writing updates to the code. Oregon sits on the Cascadia subduction zone, a huge area running from British Columbia to Northern California where the Juan de Fuca tectonic plate slides under the North American plate. This massive area locks up, and releases approximately every 300 years, resulting in enormous Richter 9.5 earthquakes, more powerful than any historically recorded in North America. The 1000AD quake dumped a cubic mile of Larch Mountain into the Columbia, creating the "bridge of the gods" of indian lore. The 1700AD quake created a tsunami so powerful that the waves dumped sand on top of 100 foot cliffs.

The next quake will probably collapse a large part of Oregon's older buildings, with enormous loss of life. There is a 10% chance that will occur over the next 30 years. Our 1960 house was well built, with big strong beams and sill bolts, and can probably survive a Richter 7. However, a Richter 9, with 30 times the ground movement, could twist the house on its foundations, shearing at the south basement wall and at the stairway.

No wires run across the top of ceiling beams, and most along-beam wires are underneath a board running down the spine of the house.

RoofLeak (last edited 2011-01-23 00:20:53 by KeithLofstrom)