Dielectric Grease

Dielectric grease is a non-conductive, silicone grease designed to seal out moisture and, therefore, prevent corrosion on electrical connectors. Being non-conductive, it does not enhance the flow of electrical current. This property makes it an ideal lubricant and sealant for the rubber portions of electrical connectors.

Dielectric grease is typically a translucent, grey substance that is insoluble in substances such as ethanol, methanol, mineral oil, and water. It is soluble, however, in the industrial solvent methyl ethyl ketone (MEK) and mineral spirit. It is important to note that dielectric grease will melt silicone rubber over time, and thus should not be used on connectors, such as o-rings, that are made of this rubber.

While the indicated use of dielectric grease calls for it to be used only on the non-metal parts of a connection, it has been shown to be effective at preventing corrosion when applied directly to the metal connectors as well. Care should be taken when using it in this way, because this application can, in some instances, cause the connection to stop working. A common reason for such a failure is that the grease has not been pushed entirely out of the way between the two points of contact.

Dielectric grease is most widely used as a sealant for spark plugs, and is applied to the rubber boot of the plug wire. The grease not only helps the boot slide onto the ceramic portion of the plug, but prevents dirt, moisture, sand, and other foreign objects from contaminating the seal, and compromising the electrical current. Dielectric grease is also commonly used on the gaskets of multi-pin connectors in car and marine engines.

It can withstand high temperatures, making it an ideal substance for use in engine compartments and other similar locations. Most standard brands of dielectric grease are rated to 392° F (200° C), and many can operate at up to 500° F (260° C).

Aside from sealing spark plugs, dielectric grease is often used to lubricate other engine-related parts, such as rotors, distributor caps, and speedometer cables. It is also employed in many other situations where electrical connections may be exposed to moisture and dirt. These can include outdoor lights, satellite television installations, trailer hitches, and battery terminals.

Dielectric grease protects electrical connections and wiring from salt, dirt and corrosion. Extends the life of bulb sockets. Prevents voltage leakage around any electrical connection. Also prevents spark plugs from fusing to boots. Required for modern high energy ignition systems.