Grandfathering - John Dunn, Consultant, Ambertec, P.E., P.C.

When my son entered college in Boston, he moved into a dormitory that was located in a brownstone building on the tree-lined and really beautiful Commonwealth Avenue. He set up a table where he put his PC, plugged it in and in just a few minutes, he got an electric shock between the PC cabinet and a nearby steam radiator.

I measured the voltage between the two. It was half of the wall outlet voltage. Clearly the cabinet had no circuit path to ground and the input line EMI filter was doing a two-to-one voltage division effect to the cabinet.

The wall outlet was a two-prong socket, not the three prong type you see today.  Of course, the building was very old and once upon a time, sockets like this were not commonly used.

Lacking that third prong for ground, my son tried using one of these adapters:  

The PC case was still hot with half the line voltage. I discovered that there was no ground at that wall outlet. The wall outlet plate was not grounded, it was floating. 

I started looking and checking around the building. None of the wall switch or wall outlet plates were grounded. Even worse, there was a circuit breaker panel in the hallway which had wires sticking out into the walking area, wires that were live with full line voltage. Talking to building management about all of this got me nowhere. They were not the least bit interested.

I tried contacting the power company and they had nothing to say. I contacted various city agencies and got the same treatment. I made a lot of phone calls and since I was doing this by telephone from New York, my phone bill for that month hit a personal peak. It came to five-hundred dollars.

Finally, I got this one fellow on the phone who explained why I was not getting anyplace. The answer ran something like this.

The dormitory's brownstone building had been constructed in 1865. Records showed that it was electrified many years later in 1920. Although it needed to be in compliance with electrical codes of that year, it did not need to be modernized. It was "grandfathered" and therefore allowed to remain outdated.

I asked about those protruding live wires and how they were dealt with in the code for that year. I was told that the 1920 code was no longer available and this fellow had no idea how I should proceed.

Picture in your mind at this point, the Great Wall of China or perhaps the Great Wall of Boston.

I got an idea.

That dormitory served students from several different colleges. Boston is just full of colleges. I wrote letters to the administrative offices of every college in the city and described therein, the dangerous situation I had discovered. I asked if they were okay with exposing their students to what I considered a potentially life threatening situation in that dormitory.

At my next arrival at that building, there was a swarm of electricians at work. The whole building was being re-wired and brought up to modern code. When the work was finished, I checked.

It had been.

 

Comments

[koen weijand]

if the supply was still 1890 original 2 phase 55V balanced around zero, there was no shock condition caused by the capacitive division. so the problem was created by upgrading to 120V uniphase. that's where the student's grandfathers should have become active.
The 55V was chosen at the time as the best voltage to run carbon arc lamps.

[bandit Gangwere]

Like the song goes "Gotta kill the boy to keep his a$$ in line". Sometimes the threat of liability actually works - a tool to be used wisely. Unfortunately, too many people, scared of liability lawyers, sprinkle the "magick fairy dust" around instead of using common sense. I am thinking of all of the warnings and such to prevent idiots from doing something stupid to keeping kids from learning to accept and deal with the occasional minor injuries one expects from proper tool use (safety scissors are now required some places thru high school).

John, I would say you applied the right force to the right lever. Bully for you!