Dielectric grease vs Carbon Conductive Grease

[Stabi]

From another thread

Dielectric grease will reduce corrosion but it is not conductive.

MG Chemicals 846 Carbon Conductive Grease is a carbon-filled, electrically conductive grease. It lubricates, reduces contact resistance, repels moisture and inhibits corrosion.

While I knew that dielectric grease reduces corrosion and was non conductive, a carbon conductive grease makes much more sense to me. Are there any negatives to using it instead of dielectric grease.

 

[JDCAVE]

...I’ll add NoAlox to the discussion. I use this on my battery terminals.

Jom

 

[Bob Cofer]

...I’ll add NoAlox to the discussion. I use this on my battery terminals.

Jom

Industry standard in my business, does the job every time.

 

[catalinajack]

How about Kopr-Kote? Great for battery terminals. Copper-impregnated anti-sieze compound and anti-corrosive.

 

[twistedtree]

Industry standard in my business, does the job every time.

What business and what jobs?


I'm real interested too in when to use each. In the past few years I've been using dielectric grease more and more on connections and it's all worked fine - so far..... But I've never used a conductive grease.



I can see using a conductive grease for large, discrete connections like a battery cable, or a power feed circuit.


But for smaller multi-contact connectors, it seems that a conductive grease would be a disaster since you have a good chance of creating conductivity between the various contacts, This seems to be where a dielectric grease makes the most sense, an is just about encasing the connection point in a protective blob of grease.


And the obvious paradox with a dielectric grease is that if it's non-conductive, won't it make electrical contacts worse, not better? But what I've heard is that the wiping action of the contacts as they mate clears the grease, and all that's left is the encasing blob.

 

[rgano]

From another thread



While I knew that dielectric grease reduces corrosion and was non conductive, a carbon conductive grease makes much more sense to me. Are there any negatives to using it instead of dielectric grease.

I just got some and went out to the boat to grease up the shore power cord connections. I quickly realized that this stuff has a "leap distance" approaching the tree feet of 5200. The good thing as far as your fingers and any solid surfaces are concerned is that while looking like gooey grease, it wipes of easily enough with a paper towel. Use sparingly.

 

[SteveK]

When using it in multi wire connectors that have both positive and negative wires, the conductive grease, well will conduct. Dielectric seals, the contact points insertion clears the coating at contact point.

 

[twistedtree]

So my take is to use dielectric grease unless there is some exceptional reason to use a conductive grease, and you are certain that you can completely contain the conductive grease.


Does that sound about right?

 

[kchace]

Conductive grease should never be used on multipin connectors which are carrying low current data signals as the grease could conduct signals across the different pins. Also, conductive grease, while certainly conductive is nowhere near as conductive as copper wire. So you really don’t want a layer of it between two items that need to conduct any serious amount of current. Of course this normally isn’t a problem because connectors are designed to have a wiping action when they are mated which should push any kind of grease aside.

Ken

 

[C lectric]

Larger, heavy, widely separated lugs on buss bars, battery terminals, starter lugs and so on use almost what you want. On electrical connections , even smaller ones on terminals strips I have used NoALox for years in those applications. It was designed for aluminum to copper wire connections to stop the corrosion. In the above applications it will keep salt and oxygen out. It works well on the above described joints.

For electronic applications or any tightly spaced multi circuit applications such as plug in connections I use a silicone grease or a dielectric spray or similar with NO copper, carbon or any other conductive metallic or semi metallic additives as those additives could introduce a conductive path between those terminals/pins & sockets causing trouble..

Although some will argue that the silicone grease will insulate , and yes it will, but in the actual contact areas the grease will be scraped/squeezed out of place for contact and fill the voids keeping air or any other corrosive medium out of the joint.

 

[SteveK]

I remember back in the day, it was common practice to smother any grease on battery terminals after they were tightened. Maybe batteries leaked more, cause I also remember having to use a terminal cleaner more often than the last decade.

 

[Arc]

A hot terminal can make the grease drip. If it oozes over to another terminal you could have problems. I think dielectric is the way to go around boats

 

[caltexflanc]

You put the protectorate of your choice over the connection once it is secured. Vaseline, Corrosion X, liquid electrical tape, and any number of the aforementioned solutions. Corrosion X was my weapon of choice and never had an issue. Though I have to admit Vaseline worked pretty good on battery terminals.

 

[Barabus]

What should I use on my 50amp shore power cord? Dielectric grease or what? Batteries is an easier call.

 

[wpc691]

What should I use on my 50amp shore power cord? Dielectric grease or what? Batteries is an easier call.

I use dielectric grease. Never a problem, looks like new.

 

[High Wire]

Even 12VDC will track across the positive to negative pins on an electronics power cord on the flybridge over time due to salt in the air. Conductive grease will do the same. As others said, single conductor terminals, well spaced, and very, very clean. Don't leave any path for track to negative or ground or you will be wondering why your batteries wont hold a charge. I do not use it.

 

[FF]

For connections that stay tight , and conductive nothing beats having a star washer in the connection.

Any resistance causes heat which expands the connection while on , then shrinks when cooled.

The star washer puts pressure on the terminal ends .

Copper nuts , bolts and washers are found at a contractor electrical supply , and do a better job of passing electric than SS.


https://www.skygeek.com/military-standard-ms35333-105-washer-int-star.html

 

[JDCAVE]

I can see using a conductive grease for large, discrete connections like a battery cable...

Yes. And to be clear, I only use it at the battery terminals. CLectric suggested it’s use to me 6 or 7 years ago. There has been no corrosion at the terminals, although these are with FLA T-105’s.

Jim

 

[Steve DAntonio]

I've used Kopr Shield for years on and am very fond of it, on discrete connections, as another poster pointed out, never where it could bridge positive and negative contacts.

However, I was disappointed to learn a few years ago, on a call from one of Practical Sailor's tech testers that he could measure no improvement what so ever when using Kopr Coat over dielectric grease, none. I still use it, but it seems it may be no different than dielectric grease.

I have not used the MG Chemicals carbon grease, however, in the research I've done it does seem to have demonstrated conductivity improvement.

For shore cord connection I'd use a light corrosion inhibitor such as a silicone spray, grease attracts dust and can be messy, and once dust-loaded can create resistance issues as it can't be displaced easily.

 

[Exctyengr]

I use Dow 4, it is a professional grade dielectric. I use this on boats, cars, and aircraft

 

[EngNate]

Silicone dielectric compound is interesting stuff. Between contacts it squeezes out to a single molecule thickness and electrons flow freely through the gaps. So, it doesn't interfere with contact connections but provides insulating properties between them, and blocks moisture. It's the stuff for all kinds of electronic and electrical connectors. It's available at most auto parts stores.

T&B Kopr-shield is the stuff for bolted connections, and also a good thread lubricant and anti seize. It and other conductive compounds serve a different purpose in the contact area, filling voids in the relatively rough surface of cable terminals to reduce the resistance of the connection and block moisture from getting in the contact area. Inside compression crimp terminals it fills the gaps between cable strands and excludes moisture. Only use conductive compounds on isolated single conductor connections. Kopr-shield is a little messy, it's persistent and excess doesn't wipe off easily, it doesn't wash off hands for a while.

NoAlox is formulated for and should be used on aluminium connections. On other materials its helpful in place of nothing but I don't think it will hold up like Kopr Shield, but it's readily available.

I wouldn't put any kind of regular grease, including heavier silicones, in between any contact areas.