[BC] Now, THIS is a job!

[Mike McCarthy]

I have a piece of line from a 340KV project ComEd did here about 15 
years ago.  It's about 1.75" in diameter and heavy...about 5 lbs for 
the 2 ft. piece I have.  I have a very healthy respect for those 
towers and  the people who installed and maintain them. A couple men 
were killed on this particular line a couple years ago when working 
on the tower and got a bit too close to the live cables.

I had a friend who was part of the communications managing team at 
the company and he regularly told me of stories about how high and 
hot the company lets those cables operate.  It wasn't uncommon for 
them cables to operate at 170 deg. F or higher during the summer 
months.  As we both know, the hotter the cable the more resistance 
increases. But with direct contact to air, the cables can dissipate 
the heat too.

There is a very good reason why the utility companies are pushing for 
super conducting cables....

MM

At 08:08 PM 4/25/2007 -0500, Bill Smith wrote
>Actually, it applies to all electrical wiring. You can obviously have higher
>temp rise in outside conductors. The type of conductor is specified for the
>maximum rating and allowable sag of the conductor. Bad things happen when
>115 KV sags in 14 KV for example.
>
>Don't forget, conductors are much larger than they appear from the ground
>and currents in the several hundred amp range are not uncommon.
>
>Bill