PCB Question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Tesla729-at-cs-dot-com>

Hi all, 

I have an old (circa 1945) x-ray transformer that I strongly 
suspect has PCBs for the dielectric fluid. I have ran across 
this same type of oily fluid before in another old transformer. 
It looks like oil, but has a different odor than plain transformer 
oil. However, the dictionary definition of PCB states that it is 
in the from of a "toxic, colorless, odorless, vicous liquid form- 
erly used as an insulator in electrical equipment" I was won- 
dering if it was usually mixed with petroleum in electrical euip- 
ment and thus the definite odor. And yes, I have gotten a little 
bit on myself before when I took them apart to facilitate an in- 
ternal repair :-(( Hopefully, my hair won't start falling out tomor- 
row. 

I've read that you can drop a drop of the fluid in question into 
some water and if it floats, then in isn't PCB, as PCBs have 
a higher specific gravity than water. However, I personally do 
NOT suscribe to this as a sure-fire way to detect the presence/ 
absnece of PCBs as they may very well be mixed in with petro- 
leum oil, which of course has a lower specific gravity than water. 

Maybe some of the resident chemistry majors could comment 
on this? 

David Rieben