Like just about everything else in my Overlander,
when we first started camping both the 120 vac & 12 vdc electrical systems
were completely original with the exception of a new outlet in the
kitchen. Although I have no formal
training in either electricity or electronics, I have hobbied with both since I
was a little kid, and am quite comfortable working with both. You may not be.
But
if you are, and are looking for a little insight into what makes a vintage
Airstream tick electrically, there are a few observations worth sharing. Although I have tried to keep the
“glaze factor” down, my tendency is to drift into the minutia, so
feel free to email me for clarification if I should lose you in useless detail.
Conversely, also feel free to request additional, numbing detail. 
Click
on one of the following topics for more detail:
·
How The New
Charger Was Chosen
·
Speaking of
Battery Charging
The Wiring
Solid
aluminum wiring was all the rage in the late sixties because it was cheaper
& lighter than copper. What
aluminum wire lacked in conductivity, as compared to copper, could easily be
made up in increasing the wire’s diameter. When sized & installed by a properly
trained individual, it works great.
Unfortunately, if the correct connectors are not used, problems can
occur.
In
a nutshell, different metals expand & contract at different rates when the
temperature changes. If a wire is
connected to terminals made of metal with a different expansion/contraction
rate, after several temperature changes, the connection will loosen up. After that happens, arcing at the
connection can occur. Either the
heat from the arcing or the arc itself can prove to be a fire hazard.
It
is my understanding that a flood of improperly installed aluminum wiring forced
National Electrical Code changes banning the use of solid aluminum wire in residential applications. Stranded
aluminum wire, commonly used in high current applications, is still
allowed. Seems like I heard that
solid aluminum wire is still used in mobile homes.
Both
my Airstream, and my house use solid aluminum wiring for 120 vac circuits. My Airstream was in a great shape. My house, however, had several instances
of improper connections. If your
Airstream has aluminum wire, it would behoove you to check each outlet &
breaker to make sure it is rated for aluminum wire and that the wiring’s
screws are tight. Most home
improvement stores sell special outlets & switches rated
“Cu/Al” or “CO/AL” (copper/aluminum) wire. For what its worth, I have heard that
the terminals are made of zinc.
Copper
wire is used for the 12 volt circuits in my Overlander. Of note, my Airstream was built at the
Ohio plant. A friend of mine
with two ’67 Airstreams built
at the California plant tells me he has the opposite configuration –
Copper is used for 120 vac circuits & solid aluminum for the 12 vdc wiring.
While
my first preference would be copper for all circuits, over the long haul aluminum does not strike me as a good choice for
low voltage circuits. 12 volt
circuits have to be able to carry a lot of current since the voltage is so
low. Aluminum wire, with its lower
conductivity, has a higher voltage drop per foot than copper. 10 gauge is the biggest gauge of solid
aluminum wire, I believe, available.
Between the feeling that this gauge is too small, and the fact that
consistently good connections get more important as the bus voltage goes down,
my gut feeling is that dim lights & slow motors are more likely if aluminum
wiring is used. I see nothing
unsafe in it’s use though. [back
to top]
Power Quality
Just
because a campground has a 30 amp receptacle for one to plug into does not
necessarily mean it will provide power your Airstream is happy with. A lot of trailers at the campground all
running their air conditioners, may affect the line voltage. Ideally, you would like to measure 120
vac on your voltmeter once you plug up.
After letting your air conditioner run for half a minute or so, the
voltage will probably drop a volt or two.
As long as the voltage stays at or above 115 vac, you’re in good
shape. Be careful about running the
microwave though. I have heard of
people continuing to run the air at voltages as low as 110 vac. Not me. RV Air conditioners are too expensive to
repair when damaged by low voltage.
Also,
if you have to use an extension cord to plug your Airstream into shore power,
make sure its wiring gauge is 10
gauge or lower. Lower gauge means
thicker wire. The wiring gauge
should be stamped on the outer insulation.
If it is not, it is a cheap extension cable & should not be trusted. I only point this out because I once saw
a vendor selling an extension cord with 30 amp fittings, but the wire gauge was
12 gauge, which is only rated for 20 amps.
Using the wrong gauge can result in an unwelcome voltage drop. [back to top]
12 volt Circuit Breakers
In 1967, Airstream used three, 12 volt, 20 amp, self-resetting
circuit breakers to limit current flowing through the 12 volt DC circuits. Additionally, there is one, 25 amp
breaker in the belly which keeps an eye on the charge wire’s current.
Coincidental with replacing a bad light switch, I had one of these
breakers bite the dust. Kinda cool how simple the breakers are. The autopsy
showed the device has nothing more than a bimetallic strip with [apparently] a
certain amount of electrical resistance. When too much current is drawn, the
strip pops the circuit open. When cool, it closes.
In my case, the contacts had fused, and melted away from the
strip. The point source heating around the damaged contacts made the breaker
work in an interesting way.
Luckily, with minor modification, the breakers being sold nowadays
are physically quite similar to what I had. At $3 a pop, all three breakers
were replaced.
[back to top]
Light Switches
Everything
went fine on our first couple of camping trips. But then the kitchen sink light switch failed
in the every-bulb-ON position.
Although I could see the original switch had been made by Leviton, they
now no longer make it. Much time
was spent on the Internet, and at local lighting vendors to no avail. Although 3-position switches are still being
made, none could be found that had the shaft length needed for my light
fixture. So, at over $15/switch
plus S&H, I ordered two from an Airstream dealer.
The
previous owner must have used the kitchen sink light a lot because the
insulation on the light bulb sockets’ wires was dark & hardened. I was able to find new socket center
contact wiring at a local auto parts house.
A
couple more camping trips later, the second switch was installed in the bedroom
fixture when that switch failed.
Interestingly, the sockets’ wires did not need replacing in this
fixture.
A
couple more trips later…
Since
I could see where this was going, I broke down ordered three switches, and
replaced the rest before they could fail.
The bath fixture, judging by the wire caps used, appeared to have been
replaced before. But, to be on the
safe side, it was also replaced. My
motto is now, “Replace your light switches every 38 years whether you
need to or not…” 
[back to top]