A waterproof switch and insulated terminals are a good plan for reliability but
won't fix the problem. The switch body needs to be grounded by a separate wire
back to the trans or chassis. The lack of a ground means your body becomes the
ground path and that is what causes the shock. The moisture provides a leakage
path from the switch terminals to your wet hand. The shift lever is not a good
ground, as the grease around its base is an insulator.
When the OD switch opens, the solenoid generates a large negative voltage as
its magnetic field collapses, same principle as your ignition coil. 12V won't
give you a shock but that will. The best solution is a power diode from the
solenoid terminal to ground to suppress the kickback voltage entirely. That's
standard practice in electronic circuits since the kickback is destructive of
electronic controls and switch contacts. The striped cathode side goes to the
solenoid terminal, other side to ground. The diode conducts when the negative
voltage occurs and harmlessly shunts out the kickback. It could be mounted
right on your switch after the ground wire is added.
Example Radio Shack part
http://www.radioshack.com/product/index.jsp?productId=2062579
Regards,
Gary Schneider
----- Original Message ----
From: Rob <19to1tr6@comcast.net>
To: Friends of Triumph <fot@autox.team.net>
Sent: Saturday, March 8, 2008 2:33:31 PM
Subject: [Fot] A type OD
With all the rain in Boston today it reminds me of a problem I need to correct
My OD switch is mounted to a welded tab on the gear shift lever In a rain
race with soaking wet gloves,suit and shoes I was getting a pretty good shock
each time i activated the OD
The switch has open poles and is not water proof
Will a water proof switch and insulated mounting correct this Or will i have
other wiring considerations. thanks rob
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