The right install

not sure but common sense implies battery connection should be clean and bare to bare, then a proper sealer applied. i’m not sure though, any comments, advise, suggestions. thanks!


You are correct.


Yes, you’ve got it right!

You are absolutely right. I have seen a lot of people though who put the sealer on first. How their vehicles manage to start is beyond me.

Its really not that difficult to understand. Grease and oil are dielectrics when in a thick film, but become conductive in thin film applications. Personally for battery terminals, I like to keep them dry.

It is recomended that the grease be applied to the post first…it actually is suppose to aid contact and slow corrosion.

There seems to be a lot of misconception about dielectric grease and what it does. Dielectric grease is always an electrical insulator. It does not become conductive, even as a thin film.

Its purpose is to block out moisture and to inhibit corrosion. When applied to spark plug boots it also acts as a lubricant, helpful in later removal. Other greases act similarly but dielectric grease is superior because it has such a high melting point.

It does not promote electrical contact. You should not apply it to metal surfaces that need to make electrical contact. Use it as a sealant after ensuring there is good electrical contact. As missileman noted, coating battery posts with dielectric grease might only seal in the electricity.

Grease does not conduct electricity. Air also does not conduct electricity. Sparks travel through air and other media including grease as a discharge of buillt up capacitence because of this. Sparks do not discharge from battery terminals normally because the electrons follow the path of least resistance, which would be the metal on metal contact.

So if you assume that when you place the electrode that metal will touch approximately as much metal as it would have without the grease (most of the grease is shoved out of the mating surfaces) and that the grease is actually blocking very little contact surface that it would have otherwise, then it may make sense to apply the grease first as it will fill the small spaces that can be exposed to air.

On the other hand, if you only grease the contacts afterwards but use enough grease to cover the entire surface area, then it is unlikely that moisture will get in between the contacts anyway.

So I vote for it doesn’t reallly make a difference.

Grease does not conduct electricity.

Dielectric Grease is NON-CONDUCTIVE…But if it doesn’t say dielectric…then it’s conductive.

Grease is not conductive. Only when additives are added may it conduct electricity.

Try this one too.

Water does not conduct electricity.

It’s true.

You should not apply it to metal surfaces that need to make electrical contact. Use it as a sealant after ensuring there is good electrical contact.

SteveF, in most cases, you have to add the grease to the connections prior to assembling the parts. The terminals and sockets will displace the grease by their mating surfaces and make good electrical contact. Take your example of spark plug boots. The grease is typically inserted into the end of the boot. It will definitely get on the spark plug tower as you press the boot over it. Another good example is with plow connectors. The whole idea is to smear the grease on everything, pins and sockets, and pack it in there good before putting them together. You want it to be generous enough to squeeze out when the connectors mate. If not, I guarantee you’ll be very disappointed at the results.

When it comes to battery terminals, I’m on the dry and clean side. Maybe a felt washer. The corrosion there mainly comes from outgassing of the battery where the terminal to case seal is not perfect. Once that happens, the battery is probably getting to the point of needing to be replaced anyway IMO.

@nebin…The point is…you have to get dielectric grease if you don’t want it to conduct electricity.

Yes I know water is NOT conductive…but I sure as heck wouldn’t stand in a puddle while doing electrical work…would you???

Points taken.

Pure water may not be conductive, but when you add minerals and other goodies, that changes things.

Protective grease like commercial di electric grease is applied to both surfaces to be connected. It is done that way for maximum protection on ALL automotive connectors you want protected whether they be simple plug connectors or battery terninals. Read the directions !

My recap, dielectric grease is non conductive. The grease provides an environment to inhibit corrosion. Good contact with the grease in place is paramount as a poor connection will be inhibited. That is the new thing I learned today.

SteveF, nebin, MikeinNH, irlandes and anyone else. All oils and greases, including dielectric grease are conductive in thin film applications.

Dielectric grease is used to coat the HV connections in the power distribution industry. all internal connections are made under “insulating” oil.

So are you guys saying that every electrical engineer in the country is wrong?

Some seem to be hung up on this non conductivity…as if a thin film of grease is somehow going to inhibit the flow of electricity.