FOLLOWUP: What Wednesday’s big West Seattle-and-beyond power outage had in common with outage days earlier

| Utilities | West Seattle news

Early Wednesday, more than 8,000 Seattle City Light customers from Highland Park to Burien lost power. The image above, from SCL’s outage map, shows the outage zone at its peak; half the affected homes/businesses got power back after about three hours, and less than an hour after that, the outage was down to 585 customers. But the problem affected thousands more people because it happened along a highway, closed all lanes, and jammed traffic through much of the morning commute. So what exactly happened? We asked SCL’s Julie Moore, who responded today, explaining the cause resembled what took out ~2,000 customers last Friday/Saturday:

The outage cause was similar to the one last Friday. While doing a planned maintenance project, a piece of equipment failed and the overhead pulling rope dropped down on to our primary voltage electrical system, causing the lines to fault. We again needed a clearance – when we intentionally cut power to a particular area –for the electrical workers to safely remove the pulling rope from the primary lines and then we were able to restore the system to its normal configuration.

It is unusual for this piece of equipment to fail and we are looking into why it failed. The work being done is designed to replace and upgrade older static wire and replace with a new wire that has an optic cable capability. This work is still ongoing and the targeted completion date is the end of August.

Maggie August 19, 2021 (4:54 pm)

Ok, I experienced both outages and when I heard the cause of yesterday’s outage I was like, that sure sounds like the same thing that happened on Friday! Is the wire that is newly installed at risk of breaking? I live by those giant power poles that they were doing this work on in Highland Park – am I at risk for some sketchy wire coming down near my house?

John Smith August 19, 2021 (9:32 pm)

Maggie, I don’t think you need to worry. Here’s a quote from the article: “we intentionally cut power to a particular area –for the electrical workers to safely remove the pulling rope from the primary lines”The “pulling rope” is like a messenger line on a ship. It is put in place before the wire is pulled. If you drive by and look at the operation, the pulling rope is probably the orange line. The pulling line is only used to pull the electrical line into place. Sorry about the yellow color. I don’t know how to undo it.
- John Smith August 19, 2021 (10:57 pm)
  
  Well, maybe the “pulling rope” is also used to exert a pre-engineered amount of tension on the electrical wire… dunno. It seems to me that either the winch for the “pulling rope” failed to hold tension or someone didn’t dog it off correctly. Either way, I think it’s time for Seattle City Light to shut down the project to determine what is going wrong, then fix it. Once, OK, maybe. Twice, no.

Peter August 19, 2021 (8:49 pm)

This is why it’s a good idea to prepare now in the event of a natural disaster in the future. The power could be out for months and we will be on our own.