Di-electric grease

Brewsterbuff

Brewsterbuff

Senior Member
Is Di-electric grease a conductor or an insulator? I was always under the impression it was a conductor, put it on my battery clamps and a thin coating on the light bulbs to reduce corrosion and make a better connection. I used it on all the old cars and on several trailers. It never gave me a problem? Recently a battery guy laughed, said I was wrong, it was an insulator and would weaken my connections. Cold here today. ??? tomorrow.
 
Very common misconception stemming from the fact that putting dielectric grease on the surfaces in an electrical connection improves performance long-term. While the grease itself is NOT conductive, in most cases it will squish out of the way when the components are attached, so it doesn’t impede the circuit. Because the non-touching parts of the connection are now coated with grease, they don’t corrode over the course of time. This improves the health of the connection long-term and is why it’s a common practice among mechanics to do this.

You can buy conductive grease but it’s a lot more expensive. Better used to fix specific problems than prophylactically in every connection.
 
Conductive grease I use is "No-Al-Ox" which is a grease heavy in graphite and originally developed for use with Aluminum house wiring. Most large diameter "service" wiring is still aluminum and it finds its use there. In the 1970s and 80s, 14 or 12ga aluminum wire was commonly used for wall wiring - and most of the connections were against copper.

Aluminum is a dandy conductor, but has a downside in that it develops "skin oxidation" - which is thin - but insulating. Aluminum wires developed "hot spots" at connections and MANY houses burned down as a result.

Today, any electrical connection I think "challenged" (both copper/bronze or Aluminum/bronze/anything else) I use No-Al-Ox in the joint.

I like it for battery posts. (Lead clamp/lead coated copper post) Wipe off the excess, and then give it a spray afterward with the red dielectric anti-oxide coating.

https://www.amazon.com/30-030-Noalox-Anti-Oxidant-Compound-Squeeze/dp/B000LDE7V4/ref=sr_1_1?crid=39FZXI4KPETCC&dib=eyJ2IjoiMSJ9.Y0fNLun3BonCd_UUhulFqYb3IU62hsFz8szPRaR3qC0X6e-2nW4AkpjWzlTdHZJnl4AYwvk4yq5Uo4-_LVJStQU6wrfJRhtKVpaPV58vnGlqOBZCYt2C1TKZYnqgSN9x.MbFdQq9EuySnxILmc-R4YMi2czL7YE8vCFgU-ESYnXA&dib_tag=se&keywords=No+Al+OX&qid=1740946237&sprefix=no+al+ox%2Caps%2C134&sr=8-1


Joe K
 
McMaster Carr sells and electrical grease that had copper particles in it. That grease is conductive.
 
I've used Never Seize for battery cables for about 60 years, no corrosion and makes good contact.
 
Dow Corning DC-4 silicon based grease has a lot of uses in electrical connections and is a product that came to use for the prevention of flash over in high tension connections such as high voltage power systems and magnetos. It was used during and just before WWII for aviation ignition systems and it's still my go to product for that and cannon plugs as well as plain terminal connections.

Most pin type connections and spring type connections such as magneto distributor cap connections, benefit greatly for both flash over and anti corrosion treatment. As long as a terminal connection it tight under tension, the metal to metal contact will force the grease out and allow sufficient electrical contact.

I also use it on aircraft spin on oil filter seals. A torque is required on them at installation but getting them off is another story. The DC-4 will work better than motor oil in a long term connection there and it makes it a lot easier to remove the filter when it's due.
 
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Joe K said:
Conductive grease I use is "No-Al-Ox" which is a grease heavy in graphite and originally developed for use with Aluminum house wiring. Most large diameter "service" wiring is still aluminum and it finds its use there. In the 1970s and 80s, 14 or 12ga aluminum wire was commonly used for wall wiring - and most of the connections were against copper.

Aluminum is a dandy conductor, but has a downside in that it develops "skin oxidation" - which is thin - but insulating. Aluminum wires developed "hot spots" at connections and MANY houses burned down as a result.

Today, any electrical connection I think "challenged" (both copper/bronze or Aluminum/bronze/anything else) I use No-Al-Ox in the joint.

I like it for battery posts. (Lead clamp/lead coated copper post) Wipe off the excess, and then give it a spray afterward with the red dielectric anti-oxide coating.

https://www.amazon.com/30-030-Noalo...d-Squeeze/dp/B000LDE7V4/?tag=atomicindus08-20


Joe K
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My first house was built in 1973, and it had aluminum wiring. I can recall an occasion that we had company over and the air conditioning breaker kept tripping. So there we sat, with company, in a house approaching 90 degrees, butter melting all over the dinner table. When I got to looking I found that the electrical contractor had not put conductive grease on the aluminum wires in the circuit breaker box, and the oxide had built up to such an extent that it was acting as an insulator. Plus, they had not used aluminum-rated circuit breakers. Needless to say, I was POed about having to re-do something that wasn't done correctly the first time.
 
Copper was in high demand during the Vietnam war. Fortunately my house was built sometime in the early 1980's and has copper wires and plumbing.
 
Copper is more expensive so there is that but aluminum cables are used for their light weight as well. Copper is fairly heavy so it can make a difference in power transmission cables mounted up on the power poles. It's not uncommon to find it at the power meter or as a substitute even in underground installations as long as it's well water proofed. Copper corrodes too so a dose of preventative is always a good idea.
 
I worked for a transport company for 37 years. From day one I was told to use N0-OX-ID on all electrical connections on the equipment, especially all light bulb connections. In all 37 years I have never seen any problems with corrosion in the light sockets, battery connections, etc. I've had a pint can in my personal tool box at home for years that I use all the time. A little goes a long way.

Just my 2¢ for what it's worth.
 
Martin31 said:
I worked for a transport company for 37 years. From day one I was told to use N0-OX-ID on all electrical connections on the equipment, especially all light bulb connections. In all 37 years I have never seen any problems with corrosion in the light sockets, battery connections, etc. I've had a pint can in my personal tool box at home for years that I use all the time. A little goes a long way.

Just my 2¢ for what it's worth.
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Sanchem NO-OX-ID-A has been a standard for over 100 years. Ma Bell bought it by the gallon for every central office install. A small tube of the stuff will last a car owner for years.
 
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