Announce The Vintage Computer Forum 1117

There are still horror stories.

Installations in dense city areas are often covered in welded steel pipe just to be safe. Military guys like to put inert gases in these and attach oxygen sensors fitted to alarms.

I have personally stopped people trying to use welding equipment on such steel pipe, properly buried below red marker kevlar mats. He had a job to do, to make way for a railroad.

This was a dense fiber line, with at least 10 single mode fibers powered at 5 watts or more. These damage human tissue severely within a 10 cm radius. (The 5 watts are in a beam just 9 nm wide).

You also need to get the right plans. Actually getting updates into the system of municipal, energy and telco engineering can be a large challenge.

I have a friend who was immensly lucky; he fell onto the 75 kV rails in a secondary grid installation; but was caught by the personell net. His wrench was not. Bright spark followed by 125 000 subscribers without power.

The wrench was never seen again, and the buttociated noise and light gave him shellshock; and probably contributed to reduced hearing.

The fuse that blew was 4 kA, 105 kV, three phase plus floating neutral.

-- mrr