In the Shop
As a farm machinery mechanic and writer, Dan brings a hands-on approach that only a pro can muster. Along with his In the Shop blog, Dan writes a column by the same name as well as the Shop Series for Farm Journal magazine. Always providing practical information, he is a master at tackling technical topics and making them easy for all of our readers to understand. He and his wife, Becky, live near Bouton, Iowa.
Aug 23, 2009
I've used it for years because some manufacturers recommend it, but finally understand the principle behind dielectric compound. I was researching a story that will run in Farm Journal Magazine this winter, and had reason to research whether this Vaseline-like goop is good, bad or useless.
Dielectric compound is a non-conductive, water repellent lubricant recommended for use in electrical connectors used under "severe conditions." That would be most agricultural applications. At first glance, dielectric compound is a little confusing because "dielectric" means "non-conductive." So what's the theory behind putting a non-conductive product in electrical connectors?
The theory is that when you plug together an electrical connector, the male pins and female sockets are a friction fit that squeezes out the dielectric compound so there is good metal-to-metal contact. The dielectric compound, being non-conductive, insulates each pin/socket against minute leaks of voltage from adjacent pins. The lubricative qualities of the compound make it easier to plug and unplug the connector, and the water-repellent nature helps seal out moisture and dust that is such a headache in electrical systems on farm equipment.
So, in short, dielectric compound--aka "dielectric grease"-- does exactly what its name implies, and does it well. It insulates pins within electrical connectors to prevent voltage leaks. It lubricates to ease plugging and unplugging connectors. It seals out moisture and reduces problems with dreaded "green pin syndrome" due to water-corroded electrical connectors.
And, if you're thinking that you could achieve the same results with plain ol' bearing grease, my research indicates that plain ol' bearing grease doesn't have the same insulating and water repellent characteristics as dielectric compound. Some bearing greases actually absorb and "hold" moisture, which would be bad in electrical connectors. Plus, petroleum-based greases can attack and literally dissolve some types of rubber or plastic used in electrical system connectors and wiring harnesses.
You can get dielectric compound at many auto parts stores, electronic supply retailers and at some farm equipment dealerships.