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It is obvious that grease is for lubricating moving parts to reduce friction and prevent excessive wear and tear. Grease also protects metal surfaces from rust and corrosion by keeping moisture away.
There are several types of grease used in mechanical and electrical installations. In electrical installations, grease is used to lubricate contacts and protect them from oxidation and corrosion. It provides a non-corrosive film on electrical switches and connectors.
Types of Electrical Contact Grease
There are two types of electrical contact grease, dielectric and conductive grease. Dielectric grease a.k.a silicon grease is an insulative type of grease that inhibits the flow of electricity away from an electrical contact in addition to protecting it from oxidation and corrosion. It is the best type of grease for reducing parasitic power loss at electrical contacts.
One of the most common uses of dielectric grease is on battery terminals to protect them from corroding. Auto mechanics also apply silicon grease on spark plugs to prevent the loss of spark as part of car tuning.
The second type of electrical contact grease is conductive grease. It helps to improve electrical conductivity on electrical contact points. In this article, we’ll look at conductive grease, its uses, and where you can apply it in your projects.
What is conductive grease?
As I mentioned, conductive grease is a type of electrical contract grease. Its purpose is to improve conductivity at electrical contact points.
Unlike dielectric grease which inhibits the flow of electricity, conductive grease enhances the flow of electricity between contact points. It helps to improve bad electrical connections to prevent arcing, pitting, hotspots, and welds.
In electrical terms, conductive grease is a conductor while dielectric grease is an insulator.
What constitutes conductive grease? Conductive grease is basically a lubricating paste infused with materials that conduct electricity. The conductive material can be carbon/graphite or metallic.
Some of the metals used to make conductive grease include copper, lithium, zinc, aluminum, and silver. Silver grease is the best type of conductive grease because electrons in silver are freer to move than in other metals.
Uses of conductive grease
Conductive grease has many uses across many trades. Some of the common applications include:
1. Improve electrical connection in a panel
When the electrical connection of a circuit breaker in the panel becomes weak and does not improve with tightening the screw, it means you need to replace the bus bar or wire terminal.
But you can fix the problem temporarily by applying a blob of conductive grease on the contact point. This will prevent the weak connection point from arcing, welding, and even causing electrical fluctuations that may damage appliances in the house. Poor electrical contact may also overheat and sometimes cause a fire.
2. Improve the grounding of your vehicle’s electrical system
With so many functions being controlled by electrical signals in modern cars, the integrity of the electrical circuitry of a car has become supercritical. One of the most important elements is the ground connection.
The ground wire completes the electrical loop back to the negative terminal of the battery. It is often attached to the chassis of the car and/or the engine block.
When the ground connection is not good, the electronics, sensors, lights, and other electrical accessories in a car will not function properly. Also, the battery may not charge properly.
There are several reasons why a car would have a bad ground wire connection but the two common ones are loose terminal connection and oxidation/corrosion at the contact point.
You can fix a loose ground terminal of a car easily by tightening the screw with a wrench or screwdriver. On the other hand, you can fix an oxidized or rusted ground terminal by cleaning the connection point with vinegar or abrasive material, then applying electrical contact grease, and tightening the connection.
Although you can use dielectric grease on the ground terminal, you will get better results with conductive grease. Conductive grease will not only seal the electrical connection from atmospheric moisture to prevent oxidation and corrosion but also improve electrical conductivity. Even if the ground terminal screw loosens up again, the conductive grease will prevent it from resulting in catastrophic failure of the vehicle’s electrical system.
3. Use as battery terminal grease
Lead acid battery posts and terminals are prone to oxidation and corrosion. This is why you should clean them regularly (preferrably with a battery terminal cleaner) and apply grease to seal off atmospheric moisture.
Most mechanics will recommend vaseline as a battery terminal grease but it does not work well in high temperatures. Vaseline and any other petroleum-based grease will break down under high temperatures in the engine bay or in the summer heat.
A better alternative is silicon grease because it has a wider temperature range. Unfortunately, silicone grease is insulative. It will affect the electrical connection on the battery if it gets in between the terminal connector and the battery post.
This makes conductive grease best anti-corrosion paste for battery terminals. It repels dirt and inhibits corrosion just like dielectric grease. But the main advantage is that it improves electrical conductivity at the battery terminal connection. In other words, you will still have a solid electrical connection even when the conductive grease enters between the terminal connector and the battery post.
4. Protect outdoor bulbs and bulb sockets from burning
If your outside light bulb keeps blowing it could probably be because of poor contact in the socket causing it to overheat and burn out. The socket may also become brittle as a result and burn also. You can quickly fix this problem by applying a dab of conductive grease to the connection point. However, be careful not to shortcircuit the hot and neutral terminals. Conductive grease will improve conductivity in the bulb socket to prevent overheating.
5. Anti-seize for light bulbs
Sometimes screw-type bulbs for outdoor corrode and get stuck in the socket and become difficult to remove. To avoid this situation, some people apply a thin layer of regular grease to act as anti-seize. Unfortunately, regular grease is a poor conductor and may cause poor electrical connection at the socket. Conductive grease is the best anti-seize compound you can apply to the bulbs. It will prevent the bulb from getting stuck in the socket and will not compromise the quality of the electrical contact. The only thing you should avoid is applying too much grease that will flow to the hot terminal and cause an electrical short circuit.
6. Improve electrical conductivity of sensor connectors
Electrical sensors are sensitive to small fluctuations in electrical signals. You use electrical grease to improve the electrical contact of sensors.
7. Improve electrical connections in vibration-prone areas
Vibration can cause the electrical connection of terminated wires, switches, breakers, and fuses to break or become loose. This can cause rattling at the contact point with may result in sparking, overheating, and parasitic voltage drop.
You can make the problem less severe by applying conductive grease to the connection points in vibration areas. The grease will help to maintain a sound electrical connection even when the contacts become mechanically loose due to vibration.
However, the ultimate fix for electrical connections that are affected by vibration is to inspect them regularly and tighten them.
8. Prevent galvanic corrosion
Galvanic corrosion occurs when two dissimilar metals are in an electrical contact with each other. The more passive metal gets galvanized by the active metal. For instance, a copper terminal will eat away an aluminum terminal when they are electrically connected.
Environmental factors such as sea water and atmospheric moisture act as an electrolyte to accerate the reaction of dissimar metals. This is why galvanic corrosion is more common in marine equipment or in the salt belt regions.
One way to prevent galvanic corrosion is to apply conductive grease between the contacts. The grease will seal the contact from environmental factors to keep the corrosion down and the electrical contact sound.
In summary conductive grease is an essential type of electrical contact grease for preventing oxidation and corrosion while improving electrical connections to prevent arcing, welds, and overheating in electrical contacts.
Despite its advaantages, conductive grease can cause electrical hazard if it gets to the wrong places. For instance, the grease will cause a short circuit when it gets between live and neutral/ground in AC applications or positive (+) and negative (-) in DC applications.
In other words, electrically conductive grease can be problematic when it gets between contacts that should be electrically separated. So, you should make sure you apply just the right amount on a contact point and wipe off the excess.
What I have found to work even better is to apply conductive grease on an electrical connection, wipe off excess grease, and seal the connection with a generous amount of dielectric grease. This keeps the conductive grease from flowing to unintended areas.
Because conductive grease and dielectric grease are both branded as electrical contact grease, you can easily test if the grease is conductive by doing a continuity test or ohm’s test with with a multimeter. Typically, conductive grease has low resistance (<1kΩ) and will test positive for continuity test whereas non-conductive grease will have very high resistance (in the range of mehaohms) and won’t conduct electricity.