Discuss Conductive grease? in the UK Electrical Forum area at ElectriciansForums.net

Cheers, I've been taught to use vaseline for most things or food grade grease! The fitters were talking about it today wondering why we didn't use copperslip for things, as they pretty much slather it on it anything with threads well, within reason, some things don't want for it ofcourse. Just wondered if anyone did use anything in particular.
 
I was told by the Electrical Engineer on my last site that Vaseline was an insulator, he used to ------- the panel builders that used Vaseline on the bus bars on any sites he commissioned.

Mind you, he might have been talking c**p!
 
Vaseline and greases are insulators, but that doesn't mean they won't benefit a connection. When you clamp up a lug or screw a conduit joint together it might look like there are a few square inches of metal-to-metal contact. Instead, at a molecular level, the total amount of surface in contact is more like the head of a pin and yet that is where all the current flow takes place. The grease's job is to exclude moisture and air so that those tiny conductive paths don't oxidise and corrode over time.

The mechanical pressure on the contact points is huge so any grease is well and truly squeezed out of the way into the voids that form most of the visible surface, so it make little difference whether it is an insulator or conductor itself. Grease with suspended metal could form additional paths, but copper particles on a steel-steel joint could also encourage the kind of electrolytic corrosion that the grease is there to prevent.

Aluminium is a different kettle of fish and not to be compared with joints in copper or steel. Exposed to air, it forms a tough insulating oxide coating almost instantly, so it needs special techniques to make a reliable connection. That is one of the reasons why it was unsuccessful for housewiring.

If your new conduit joints are having an effect on your Zs, you need to quit doing them up with a clothes peg and buy a wrench! It's after a few decades of exposure that the effect of the grease begins to show up, as a corroded threaded joint can go completely open circuit.
 
Last edited:
very true lucien.

I have done a ali cable jointing course and the crimps came filled with a silicone like substance that oozed out when crimped.
 

Reply to Conductive grease? in the UK Electrical Forum area at ElectriciansForums.net

Similar Threads

After conducting a recent EICR I found among other things that the Galvanised columns in the carpark area of this premises seem to be connected...
Replies
10
Views
2K
Hi all, Been browsing these forums for a while, always great to learn a new way to skin the same cat. Anyway, cut a long story short, was an...
Replies
11
Views
653
Doing a kitchen job for my daughter’s music teacher, who also happens to have been in my wife’s class at school. Nothing big… just a little...
Replies
2
Views
242
Hi. Im looking for some advice when calculating submain cables. Basically there is a new connection of 80Amps that is to be used for a dwelling...
Replies
5
Views
385
Was having a poke around the old man's house today. Anyway. DB is under stairs (18th ed following a recent extension. Not done by me but it's...
Replies
7
Views
718

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock