On 11/22/2013 10:15 PM, Nightcrawler® wrote:

"Dean Hoffman" " wrote in message
...

The instructor at my last code refresher class talked about properly
torquing wiring connections. He said he went through a building one
time checking the connections. Few or none were torqued properly.
I'm just curious if any of the pros here actually torque connections.
A quarter turn from breaking the screw is how people in my
acquaintance do it. Me included.

If the termination is phillips, or blade, there really is not a need since
max torque is easily achieved.

Using nuts and bolts and/or allen head, all the time. I always carried
around one of those all in one handbooks from Ace Hardware. This book
is like a little almanac for "you name it". In this book it has a listing
of torque tables for size and grade of different size bolts. Plus the
conversion formulae for converting to and from inch pounds (usually what
terminals
and lugs are listed under).

Lugs are not structural and the lug is not steel. The handbook torque
values are likely way too high.

I also managed to get a listing of all the
inch pound torque specs for Burndy lugs (ubiquitous) and used this as a
bookmark. Look up the size of the allen head and figure out the foot pounds
of torque for the torque wrench.

That is a good source, but the torque recommended by the manufacturer of
the lug should be used.

I seldom use a torque wrench unless the wire is quite large.


Usually it is not under torquing, but over torquing that is a problem.

I believe that is correct. Aluminum, in particular, can compress and
"creep" with too high a torque.

Some
of the lug housings may be split rather easily, and when you split a
hard to
get lug on a $1000.00 plus circuit breaker or motor-starter for the
first time,
that little torque wrench in the tool box becomes your friend when it
comes to
the final five seconds of an install turning into a couple of days
waiting for
one stupid lug to be located and express shipped.

Some lugs have very short set screws. I hate them. Unless you are maxing
the
barrel out, putting the proper torque will drive the set screw past the
threads.
Since the thread counts and dimensions are rather universal, I kept a
supply of
the most common sizes in allen type, extra long. I'd pull the short ones
and
toss them in the trash.

What a great idea. You start with an engineered lug where expansion
rates are critical for a reliable connection, and replace the screw from
elsewhere. Steel would be a particularly bad idea.
Did you install the lug that failed for Danny?

You shouldn't drive the screw past the threads if you are using a wire
size within the rated (minimum size) capacity of the lug.

I also kept a supply of the most common types of
lugs I might encounter in a grab box, in sets of four. There are certain
things
that seem stupid to keep on hand at all times, but when in need. Hell, I
bought
a wire fed welder for those moments when drilling and tapping just plain
sucks.
Damn, I ran out of 3/8's bolts or strut nuts. It is metal, weld the
beotch.:-)