[AT] OT - Electric horse fence

[Stephen Offiler]

On Mon, Jul 13, 2015 at 7:36 PM, Dave Rotigel <rotigel at me.com> wrote:

> At one time when copper and Al wires were spliced together the
> recomendation was to use a grease sort of paste (don't recall it's name) in
> order to achieve a good connection. Is that still the case?
>         Dave
> PS, Just found
> http://homeguides.sfgate.com/problems-aluminum-copper-wire-electricity-86313.html
> (It's worth a read.)
>
>
The short answer is hell yes.  The paste is called antioxidant paste, and
one common trade name is NoAlOx.  The info in your link is very good.  The
paste is not the only factor; it does nothing but protect the aluminum from
corrosion (and corrosion naturally happens because aluminum is sacrificial
to copper on the galvanic chart).  Special connectors are also needed to
withstand the micro-motion created by the meeting of two metals with
different rates of thermal expansion.

BUT.  These factors apply to residential and commercial wiring, hidden
inside conduit or walls, that will be there for decades and MUST not create
a fire hazard, ever.  The current, but NOT the voltage, is a major factor.
Higher current loads create more heating, more thermal expansion,
accelerate corrosion, and are more sensitive to very small resistances in
the connections.

Electric fencing is none of the above.  Hidden perhaps, but it's generally
not going to be a fire hazard, and it is high voltage, very low current.

SO