The E-Sylum:  Volume 8, Number 49, November 20, 2005, Article 15

ON NICKELS AND CONDUCTIVITY

In our last issue, Nancy Green wrote: “…fuse boxes
require copper coins to make the connection. Nickel does
not conduct electricity.”

Ray Williams and Joe Boling pointed out that this is
not correct.  Joe writes: “ I beg to differ - nickel
DOES conduct electricity. The specific resistance of
nickel is 4.48 times that of copper, but it is NOT a
dielectric. And in the second place, a "nickel" is 75%
copper anyway. Now, it may be true that nickels do not
do well in fuse boxes - but that would be because the
nickel oxide on the surface has a much higher resistance
than the metallic nickel under it. “

John Nebel writes: "Nickel (14.6) is quite conductive,
more so than iron (11.2).

MIT's nickel info
a great reference, the elements traditionally used
in coinage are in group 11 and clustered around it
and are generally conductive.

As with most anything there are degrees, copper (60.7)
is one of the best conductors, only silver (62.9) is
more conductive.  Mercury (1.0), far less conductive
than nickel, has been heavily used for switching - in
thermostats, for example, a bimetallic coil tilts a
glass bulb and a blob of liquid mercury completes or
breaks the connection.  More recently, that mechanism
has been replaced with electronics using silicon (.0004),
normally not a conductor, but fortunately with certain
impurities added it semi-is or there wouldn't be modern
computers."

Gar Travis adds: "Everything you wanted to know about
nickel including conductivity..."
More on Nickel

[So please don’t take this as a green light to put
nickels or any other coin in your fuse box in place of a
fuse.  We don’t want to burn down any numismatic libraries.
Growing up, my family’s house had one of the old-style
fuse boxes with the screw-in type fuses.  Thank goodness
my Dad never got the brilliant idea to use a coin for a
temporary fuse.  Newer homes usually have the breaker-style
fuses that don’t lend themselves to this sort of shortcut.
I assume building codes in most areas require the newer
style fuse boxes, so perhaps this dangerous use of coins
will go by the wayside over time.  –Editor]

  Wayne Homren, Editor

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