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City Light: Bigger poles, thicker lines for light rail electrical infrastructure upgrade

The upgrade of Capitol Hill’s power grid continues. Seattle City Light announced a project to install thicker, sometimes taller utility poles and bigger electricity cables along a corridor connecting the East Pine substation at 22nd Ave with the light rail construction site at 10th and Denny. We’ve mapped the route and included the media release from City Light below. The agency will hold a public meeting on the project on May 25 at Miller Community Center. Details below.

CHS recently reported on this project to replace power poles along E. Harrison and E. John and a $2 million initiative to underground some areas of the Hill’s electrical system. We’ll touch base with City Light to find out how this all fits together.


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Project Will Improve Reliability, Meet Residents’ Power Needs, Supply Light Rail Station

SEATTLE — Seattle City Light will be upgrading power lines in Capitol Hill during the next year to increase their power capacity.  The work is designed to meet local power needs, improve reliability, and provide electricity to the Sound Transit light rail station now under construction.

The work involves the replacement of 36 existing utility poles with new poles that are 1 inch thicker. A few will be 5 feet taller. New wires will be up to 1 inch thicker than what is currently in service. Seattle City Light also will hang conduit for communications cables 9 feet below the topmost electrical wire.

The new poles and wire will be placed between City Light’s East Pine substation and the light rail station Sound Transit is building at 10th Avenue E and E Denny Way.

The route of the project will start at the East Pine substation at 22nd Avenue and Pine Street then go west on Pine Street to 21st Avenue, north to Olive Street, west to 20th Avenue, north to Thomas Street, west to 15thAvenue, north to continue west on Thomas to 14th Avenue, north to Harrison Street, west to 12th Avenue, south to Denny Way and west to the Sound Transit Capitol Hill light rail station at 10th Avenue.

Seattle City Light is inviting customers to discuss the project with us during a community meeting at Miller Community Center, 330 19th Ave. E., Seattle, from 6:30-8 p.m. on Tuesday, May 25th. Customers can follow the construction schedule by visiting:

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John Niles
John Niles
10 years ago

This electric upgrade is undoubtedly related to the fact that the tunnel boring machine (TBM) runs on electricity.

The TBM launched at Capitol Hill Station (CHS) will proceed twice — once per each future one-way rail tunnel — from the CHS site down to the Pine Street Stub Tunnel (PSST). All the dirt removed for each tube comes out through the station site.

A brief overall description of the future 3 mile long subway tunnel coming to the neighborhood is an 8 page paper (pdf) prepared for a 2008 tunnel conference. The paper is on a contractor’s web site.

Quoting, “The TBM for the northbound tunnel will be launched first from the CHS box after the bottom slab has been placed. This will allow for construction of the station box while the northbound running
tunnel is mined. Once the TBM reaches the PSST, the TBM will be moved back to CHS and then re-launched to mine the southbound running tunnel.”

Good luck to all involved!

CL worker
CL worker
10 years ago

Also, the ST design for the stations has all kinds of redundancy built in: Each station is fed from two separate substations so that if one sub-station goes off-line, the other on can pick up the load.