Re: [alfa] Re: grounds/dielectric grease

[aholact@xxxxxxxxxxxxx]

>Dielectric grease is an insulator so I wouldn't be putting it in the
electrical path.

****************************************************************

This is a common misconception, i.e., that grease will insulate one
connector from another.  There's no need to worry, and here's why: On a
microscopic scale connector surfaces look like the mountains of the moon.
The contact surfaces of an assembled pair of connectors (bullet, spade,
post & clamp, whatever) are like two sets of mountain ranges pressed
together, peaks to peaks.  A layer of grease (special dielectric or plain
old ordinary) *is* an insulator but it will not insulate the contacts from
one another unless there is zero clamping force and/or clearance exists, in
which case... you don't have a "connection" to begin with!  The clamping
force BTW does not have to be very great - ideally it's less than the value
that would cause galling or removal of plating on the contact surfaces,
i.e., firm not tight.

Grease does at least three good things:

1. Acts as lubricant during assembly, i.e. resists galling.
2. Encapsulates the connection, preventing oxidation of connectors after
assembly.  (Oxides are a real problem - they are effective insulators and
tend to occupy more volume than the base metal, with the consequence that
they force the connectors apart, eventually resulting in an open circuit.)
3. Resists "fret corrosion" which can increase connector resistance over
time.

See technical discussion at <
http://www.amp.com/products/technology/4jot_1.pdf>, esp the first three
sections (Abstract, Introduction and Methods to Prevent Fretting).

On a practical basis, grease can be viewed as "filling the gap" in the
insulation that encapsulates wiring and thereby protects the wire strands
from degradation.  Connectors, esp those exposed to the elements, can be
considered unprotected and are therefore candidates for encapsulation.
Best results are achieved by covering every surface, i.e. by working grease
into recesses that might begin to breed corrosion.

Chris
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