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Topic: Dielectric Grease Caution (Read 571 times) previous topic - next topic

Dielectric Grease Caution

FWIW, I have noticed over the years that we throw around the term Dielectric Grease as a cure all for electrical connections. I remembered from my professional career that some Dielectric/Silicone materials did not meet Mil Spec requirements in a number of electrical situations. I finally found out why, see below.

"Silicone grease should not be applied to (or next to) any switch contact that might experience arcing, as silicone can convert to silicon-carbide under arcing conditions, and accumulation of the silicon-carbide can cause the contacts to prematurely fail. (British Telecom had this problem in the 1970s when silicone Symel® sleeving was used in telephone exchanges. Vapour from the sleeving migrated to relay contacts and the resultant silicon-carbide caused intermittent connection.)"

This is an excerpt from Wikipedia, Silicone grease - Wikipedia, the free encyclopedia.

This is not a big deal but I thought maybe other "Inquiring Minds" would like to know.
The selected media item is not currently available.Kent Speers
Locust Grove, OK
1993 U300 SSE 40' (Restored at FOT 2009) Build 4323
720 watts Solar
6V92TA DDEC Silver Engine
2014 Subaru Outback

Re: Dielectric Grease Caution

Reply #1 –
Quote from: Kent Speers –
FWIW, I have noticed over the years that we throw around the term Dielectric Grease as a cure all for electrical connections. I remembered from my professional career that some Dielectric/Silicone materials did not meet Mil Spec requirements in a number of electrical situations. I finally found out why, see below.

"Silicone grease should not be applied to (or next to) any switch contact that might experience arcing, as silicone can convert to silicon-carbide under arcing conditions, and accumulation of the silicon-carbide can cause the contacts to prematurely fail. (British Telecom had this problem in the 1970s when silicone Symel® sleeving was used in telephone exchanges. Vapour from the sleeving migrated to relay contacts and the resultant silicon-carbide caused intermittent connection.)"

This is an excerpt from Wikipedia, Silicone grease - Wikipedia, the free encyclopedia.

This is not a big deal but I thought maybe other "Inquiring Minds" would like to know.
Reason for inspecting/cleaning contacts and other points where corrosion may occur and silicone/dielectric grease are used.  I use it in the area where the isolator and solenoids due to their location behind the rear driver side duallies.
Peter & Beth Martin
No Forrest? What have you done?
MC# 15890 until Dec 2016; FMCA #F329677
Cincinnati, OH