Which Type Of Grease Is Used To Seal Electrical Connections?

The connection between spark plugs and spark plug wires is frequently sealed with dielectric grease. Dielectric grease, often known as tune-up grease, is a silicone-based grease that repels moisture and prevents corrosion of electrical connections.

Is it OK to use silicone oil on electrical connections?

Silicone oils and silicone grease are both dielectric, and silicone is generally inexpensive and abundantly available. However, any silicone-based lubricant should not be used on electrical connectors or contacts. What is the reason for this? It’s a theoretical difference between us and other companies that sell silicone-based lubricants for electrical connectors, particularly in the low-cost automobile repair market.

Silicones have properties that make them an ideal oil or (in the case of grease) base oil; they have a broad temperature range and are very inexpensive. Apart from other silicone-based materials, silicone doesn’t usually have any compatibility concerns with rubbers and plastics. Because of their low surface energy, they can migrate and cover surfaces very effectively, albeit this migratory capacity is generally seen as a disadvantage in automobile manufacturing facilities. Silicone can polymerize into a hard, brittle material that might cause electrical difficulties and weld connectors together, which is a major concern for us. Although manufacturers and sellers of silicone dielectric oil and aerosol sprays may disagree with us, the big automakers and their tier one suppliers agree. This silicone polymerisation issue only exists in electrical lubrication applications; in mechanical lubrication applications, the brittle material would be broken down by mechanical movement; in electrical applications, there is no movement other than micro-motion or fretting, which is typically associated with vibrating equipment and/or thermo-cycling. The range of movement associated with fretting behavior is unlikely to alter the polymerization of a silicone lubricant.

Are you prepared to select an electrical connector grease? Take a look at our post on Choosing Electrical Connector Grease for more information.

For silicone sprays, this is a typical HT lead application. Silicone sprays appear to be widely used on automobile High Tension (HT) leads. People frequently tell us that they have no problems using silicone lubricants on HT lead terminations. So, isn’t this evidence that we’re wrong when we claim silicone lubricants shouldn’t be used in electrical applications? The answer, like most things in engineering, is not simple, but there is a significant difference between the voltage that passes through an HT lead/spark plug connection and the voltage that passes through an airbag connector, a seat belt connector, a lighting connector, or a clock spring connector (old school reference!). Remember how electricity was compared to a river or a waterfall in school to help students grasp voltage and amperage? The amount of water flowing down a river or waterfall corresponds to the number of amps/current running through a circuit, while the voltages correspond to the force or push of that river flow/waterfall. In an HT lead application, high voltage or force/push is used to break through any polymerisation of silicone, but in a more sensitive application (for example, an airbag, lighting, or ABS connector), the voltage is much lower. HT leads can carry 5,000 or 10,000 volts, whereas a lighting connector may carry 12 or 24 volts, and more sensitive circuitry connectors in a vehicle may carry millivolts. This polymerization is a concern in lower voltage applications/connectors, but it is unlikely to be a problem in high voltage connections.

Our most affordable dielectric connector grease is made of Polyalphaolefin (PAO), which we found to be ideal for lubricating electrical connectors and contacts. If the finished grease is to be used on electrical/electronic connectors, it is obviously critical that the basic oil be accompanied by an adequate thickening. If the phrases ‘base oil’ and ‘thickener’ are unfamiliar or puzzling to you, you might want to view our video, which explains the terminologies and how a grease is made:

While a silicone-based lubricant may appear to function in the short term, their long-term performance is poor, and since our goal is long-term satisfaction, practically “lube for life,” we would not recommend a silicone spray, silicone oil, or silicone-based grease for electrical applications.

Another difficulty with silicones is silicone sprays in particular. Silicone sprays are not permitted in vehicle manufacturing plants. Of course, if the reader is not a member of an automotive manufacturing team, this information may be irrelevant, but if any painting or body work repair is planned, the reader may be interested…

Cratering and fisheyes appeared on painted surfaces a few decades ago, causing concern among vehicle makers. Light molecular weight silicone sprays used in vehicle assembly plants were discovered to be the source of the problem. When light molecular weight silicone flies through the air, it can settle in unexpected places, contaminating sheet metal. Silicone sprays are often clear, making them difficult to detect during the painting process and causing a slew of problems in the paint shop. As a result, silicones are not permitted in the manufacturing or assembly of vehicle parts.

Take a look at our post on the “Facts and Myths of Electrical Connector Lubricants”…full it’s of interesting information! For example:

What is the best conductive grease?

Some people believe that dielectric grease is conductive or abrasive because it contains silica, which accelerates wear. (There is no silica in it.)

Dielectric grease insulates connections, making them less conductive, according to the most common Internet complaint. Pure silicone grease is referred to as “insulating grease” by some. The word “dielectric” in the name serves as a general foundation for this argument. Because “dielectrics” are insulators, the name “dielectric” is considered to imply that the connection will have future problems. In general, authors expect powdered metal greases (also known as “conductive greases”) to increase or sustain connection quality over time, whereas dielectric greases will isolate connections since “that is what dielectrics do.”

My first encounter with silicone grease was as a lubricant in record turntables in the 1960s. On turret-type television tuners, where channel coil packs or “strips” were mounted in a rotary turret, it was also often employed as a lubricant and protectant. The transparent silicon grease (which replaced a green or red petroleum grease) lubricated the contacts and kept air off the plated surfaces as the turret rotated, moving different channel strips over stationary contacts to choose each channel. After experiencing field failures due to faulty electrical contact connections in new modular televisions, RCA, Motorola, and Magnavox advised pure silicon grease as a contact protectant. They delivered kits with pure silicone that could be applied straight to module contacts. Connection concerns between circuit modules, pins, and sockets were minimized with this 100 percent pure silicone dielectric grease. Silicone grease was used on signal and high voltage connections on hundreds of thousands of TV sets with hundreds of connections in each TV. Silicone grease was also used to lubricate frequently-switched gold or silver plated contacts, as well as contacts on low voltage signal level modules. To prevent or lessen corona, silicone grease was applied directly to high voltage CRT anode connectors.

My second job was in the cable television industry. As a systems engineer, I was drawn to CATV/MATV signal loss, radiation, and intrusion issues. Dry connections that corroded were a problem, as were aluminum trunk cable shield connections protected by Noalox, a lubricant that people often refer to as “conductive.” Silicone grease that was “non-conductive” solved all of these issues. The first oil and sealer I used in the systems was a white Teflon-silicone lubricant from an Elyria, Ohio-based manufacturer. While the grease fixed difficulties, applying it to tens of thousands of fittings was too expensive. It was also unattractive since service personnel left white fingerprints all over the place. I went to a GE 100 percent pure silicone dielectric grease in all CATV fittings after checking with numerous grease manufacturers. We utilized the grease in hundreds of thousands of connectors without incident for many years, totally flooding F connectors that were directly exposed to snow or rain.

Today, I still use silicone dielectric grease. I use it to lubricate the O-rings and threads of coaxial connectors. It’s what I use to keep stainless bolts and nuts from galling. It comes in handy for plug-in connections, which I use a lot in my automotive hobby. For battery terminal connection preservation, I also use silicone dielectric grease, which I apply directly to the battery post. I use it liberally on ground connections to protect stainless-to-zinc (galvanized), lead-to-lead, stainless-to-copper, and stainless-to-aluminum electrical connections against corrosion.

I’ve never had a problem with silicone dielectric compound causing increased resistance or wear. We use it to lubricate and preserve contact plating in very low current meter switches in new equipment construction. I use it on spark plug HV boots on race engines and in high voltage connectors since it has never produced shorts across insulation. In my EFI system, I also employ direct on contacts, including low voltage sensors.

Silicone vs. Petroleum Grease

Years ago, petroleum grease (Vaseline) was recommended (and appears to have been used) in low-power antenna installations. While some individuals claim to have had no issues with it, I never use it in my installs. Vaseline’s main flaw is its extremely low melting point. The majority of brands or varieties liquefy at roughly 100 degrees Fahrenheit, which is just above body temperature. While this may be beneficial in medical applications such as coating human skin, it is a major issue in connection applications. Vaseline will run when exposed to heat and will eventually dry out.

Vaseline’s production of flammable vapor, even at moderate temperatures, is a second petroleum jelly concern. A cotton ball saturated in Vaseline can burn for a long time and can even be used to start a fire. Petroleum jelly isn’t the ideal option because connectors are frequently near insulation or other materials that can act as wicks. This is especially true in warm weather because grease migrates.

Typical Applications for Greases

Myths thrive on internet forums. Dielectric grease, according to online forums, thermally insulates connections. Dielectric grease is also said to electrically insulate connections, such as those in connectors and on battery posts, according to online forums. Neither of these statements are correct.

A 35-watt dissipation resistor was used in this test. A stack of Belleville washers is used to secure the resistor to the heatsink. Conical spring washers are what these washers are. When half collapsed, they retain a steady pressure. The use of a Belleville washer ensures that the compression or pressure against the heatsink is nearly identical between testing. Cap screw torque isn’t an influence in the Belleville’s performance.

The best outcome is at the bottom. By roughing up the heatsink with 300 grit paper, all greases were tested in “scuffed” circumstances.

Thermal resistance was considerably raised when too much dense grease, such as thick heatsink compound, was used. Because the compression pressure was insufficient to drive excess grease out of the space between the heatsink and the resistor tab, this happened. Thermal resistance dropped dramatically when the layer was thinned to a light “wipe” of oil.

Permatex Dielectric Tune Up Grease and a specific heatsink compound used on high-power transistors are virtually identical. Even 1 percent Vaseline is preferable to bare metal-on-metal.

Completely flooding the connector is totally acceptable in radio frequency low power installations, particularly at low frequencies and/or when the connector has very little air gap. Flooding a connector at high power is not recommended since most greases will carburize when exposed to an arc. Grease lowers the dielectric constant of the connector by changing the dielectric constant. The problem’s effect on the system is totally reliant on the duration of the hump in electrical degrees and the quantity of the bump. (Not everything that appears on a TDR affects performance, but it does signal a potential issue.)

Flooding with an appropriate insulating grease of low-viscosity dielectric grease is totally allowed in ordinary low voltage multiple-pin circuit connectors, such as automotive applications, unless a manufacturer cautions against it. The grease should be stable, free of metals in any form, and manufactured expressly for use as a dielectric grease. Although some Teflon-based greases are permitted, this is usually a silicone dielectric grease.

Almost any pure grease of light viscosity will suffice in single low-voltage terminals or connections, such as metal-to-metal couplings, grounds, or battery posts. Grease containing metallic particles should be handled with caution to ensure that any metal present is compatible with the metal incorporated in the grease. Embedded metal powder enhances connections only slightly, if at all, and unless the grease is matched to the connector material, the chance of base metal interaction increases.

Only pure dielectric silicone greases should be used in single high voltage connections, such as spark plug boots or other high voltage connectors (x-ray, neon sign, or HV power lines). In most cases, only a light coating or wipe is required. In the presence of moisture, dielectric grease will actually accelerate voltage breakdown across insulators. Metalized grease should never be used or allowed near HV connections.

Any grease must have a low enough viscosity to push out of the way at contact points, be water or liquid resistant, and be stable enough to remain in place as a moisture and air protectant for an extended period of time. Applying a grease that does not provide the needed tasks of excluding air and moisture and lubricating the interface to prevent galling or fretting for long periods of time would be ineffective.

Low viscosity silicone dielectric grease will NOT insulate pressure connections, contrary to Internet rumors, adverts, and articles. Silicone dielectric grease will last as long as a well selected metallic powder grease and function just as well in terms of conductivity (conductive grease). Incorrectly chosen “conductive” grease, on the other hand, can actually cause connection issues.

Unless you’re certain what you’re doing is safe, follow the instructions provided by the switch or relay maker. Very high current contacts can be lubricated, and should be lubricated, in some circumstances to prolong or extend their life. There are numerous instances where lubricating contacts hastens failure.

Low-viscosity greases can usually be applied directly to low-voltage connections. Opening or closing transient voltages, such as opening arcs from inductance back-pulse, would be considered low-voltage.

Grease composition can be influenced by contact arcs. Arcs can transform silicone greases to silicone carbide, which is extremely abrasive. Silicone grease should therefore be avoided when contacts are “hot switched” and there is a risk of arcing.

Insulators are both dielectric grease and “conductive” greases (anti-seize). The main distinction between dielectric and “conductive” greases is that “conductive” greases and anti-seize greases contain finely powdered metal. Because insulating oil suspends the finely powdered metal, it does not conduct. The metal powder suspended in the grease reduces the voltage breakdown of any arc routes.

According to certain articles, anti-seize insulates sparkplug threads, generating sparkplug or ignition problem signals. This is plainly incorrect for a variety of reasons, the most important of which is the voltages and currents involved. The main issue, I believe, was anti-seize contamination of the plug insulator. Anti-seize and other metal-loaded “conductive greases” have been shown to dramatically reduce high voltage breakdown voltages of air routes or surface path resistances of insulators in these tests. Fingerprints on insulators or insulation, or even worse, slathering “conductive grease” on them, drastically damage high voltage hold off. If a single fingerprint crosses the spark plug insulator, “conductive” grease could cause an ignition misfire warning signal.

Other articles advise using conductive lubricant on connections like those between battery terminals and an automotive battery. This notion is based on wishful thinking, according to tests, and the type of grease has little effect on terminal-to-post voltage loss.

We have a blatant contradiction once more. People who claim anti-seize protects a spark plug from the cylinder head are labeled as liars by others who claim conductive grease improves a battery terminal connection, or vice versa. When two groups make claims that are diametrically opposed, at least one of them is incorrect. Both are incorrect in this scenario. Neither group seems to grasp the concepts of resistance, current, or voltage.

All of these dielectric greases, as well as almost all other brands, improve insulation while also preserving electrical connections. They achieve this by sealing connections to keep pollutants, moisture, and air out. They help keep moisture and pollutants out of insulation by sealing insulators. They’re just as good as “conductive” grease in keeping connections together, and they don’t degrade insulation.

Historic Applications of Silicone Dielectric Grease

Silicone Dielectric Grease (and lubricant) is a lubricant with a low viscosity. The usual temperature range is between -40 and +500 degrees Fahrenheit. For protecting connections, Silicone Dielectric Grease is considerably superior to petroleum jelly or Vaseline.

Silicone grease has been used for many years. It was put to use in the following situations:

The word “dielectric” in “dielectric grease” implies that the grease should only be used to insulate. This is faulty thinking. All greases operate because of their low viscosity, which allows them to entirely push out of metal-to-metal contact areas. Dielectric grease just does a better job of insulating high voltages over long distances.

Conductive Grease

A suspended base metal powder is present in conductive greases and anti-seize chemicals. Because the suspended metal powder occupies a fraction of the space filled by insulating grease, the connection is still insulated. The grease doesn’t conduct electricity.

The working assumption behind “conductive” grease is that it squeezes out of the way when pressure is applied. This produces a thin metal powder that pierces oxides and fills gaps in theory. I’ve never been able to demonstrate connection improvement from specific conductive greases using aluminum and copper blocks with diverse surface states. In my tests, the grease appeared to just carry away the majority of the suspended powder. There has never been enough powder left to reliably reduce voltage drop across clamped connections. Even with meticulous adjustments of clamping pressure, the change in voltage drop has always been indefinable. I’d appreciate it if anyone with useful information could give it to me.

The dispersed powder causes an issue that dielectric grease does not have. The hanging metal must be completely compatible with the constrained metals. As a result, conductive grease has to be used for a specific application. The connection will eventually fail if the metals clamped are incompatible with the grease’s suspended metal powder. This is what occurred with the plugs in our CATV system. Copper, aluminum, and steel were used to make the connections. The trunk center conductors cables were copper wrapped aluminum, while the cable shields were aluminum. Aluminum shields and connectors were used on drop cables, with copper clad steel centers. Corrosion failure was far more common when conductive grease was used, according to our records. When we switched to pure dielectric grease, the rate of corrosion failure dropped dramatically, virtually to nil.

I’m not sure if conductive greases aid or are necessary in bolted or clamped connections. I believe they assist, but I’m not sure if this is the case. Because Noalox is generally less expensive than silicone dielectric greases and appears to last longer, I use it on clamped aluminum slip joints in antennas. I never use conductive greases on push-fit electrical connectors or if the metal-to-grease compatibility is a concern.

Conductive greases should be tailored to the materials clamped. Low-pressure electrical connectors and connectors with many terminals should never be utilized with conductive greases. Conductive greases should only be used in well-isolated connections with different voltages, never in high voltage connections. They should never be used in RF or signal connectors unless the connections are fastened and the material compatible grease does not bridge the insulation.

Buy NO-OX-ID A-Special Grease Direct from Sanchem!

The electrical contact grease of choice for new electrical installations and maintenance is NO-OX-ID “A-SPECIAL Electrical Grade.” NO-OX-ID electrical contact lubricant (electrical contact grease) is a conductive electrical grease that prevents rust and corrosion on metals. From low micro-power electronics to high voltage switchgear, NO-OX-ID electrical contact grease has been used in the power industry for over 65 years to prevent corrosion in electrical connectors. NO-OX-ID A-Special complies with RoHS! This substance can also be used to lubricate battery terminals. Speak with a Sanchem professional right now!

Anti Corrosion Conductive Lubricant

NO-OX-ID electrical grease protects copper, aluminum, and steel surfaces and conductors from the formation of oxides, sulfides, and other corrosion deposits. An electrical contact lubricant’s job is to prevent corrosion and lubricate the connection so that maintenance is easy. NO-OX-ID “A-Special” electrical grease protects all metal surfaces from corrosion. Battery acid, salt, dampness, and different industrial chemical fumes in the surroundings can all cause an attack. NO-OX-ID “A-Special” prevents the reformation of oxide coatings, which causes high resistance and eventual failures, when placed on aluminum connectors in joints. It’s an excellent option for battery terminal grease.

Connector makers propose NO-OX-ID A-Special electrical conductive paste for trouble-free joint connections. It’s also used to lubricate battery terminals. NO-OX-ID “A-Special” coated nuts, mounting bolts, and cotter keys will never rust or freeze, allowing for easy, trouble-free removal. Wherever the production of a corrosive product may impact the correct functioning of the metal surface, NO-OX-ID “A-Special” should be used. This electrical contact grease is simple to apply, remove, and provides long-lasting, dependable performance on a variety of metals.

NO-OX-ID electrical contact grease and terminal grease lubricant were tested on electrical terminal connectors by Practical Sailor Magazine in December 2010 (Consumer Reports for Sailboats). They put the electric grease and electrical terminal lubricant through the torture test of wire, crimp connections, and corrosion inhibitors in a salt water room for a year. NO-OX-ID electrical grease beat all other greases, lubricants, and corrosion products tested, including Boeshield T-9, according to their findings. All portions coated with Boeshield T-9 were totally rusted over, according to Practical Sailor testing. “As an electrical grease and terminal lubricant, there is only one product choice for long-term corrosion performance. The electrical grease NO-OX-ID was the only product that provided long-term protection on terminals, and it was the best value for the little amounts used and the cost of fixing issues. It’s worth it to pay a little more for a better finish.”