Dielectric Strength: Safe to Use Across 240v/415v Terminals?

AI Thread Summary
Dielectric strength indicates the voltage at which a material breaks down under electrical load. An RTV compound with a dielectric strength of approximately 500 volts/mm may be safe for use across 240v or 415v terminals spaced 3-5mm apart, provided the gap is sufficient to prevent breakdown. However, the breakdown voltage decreases with larger gaps, and testing at higher voltages, ideally ten times the operating voltage, is recommended for safety. Additionally, caution is advised as some RTVs may not cure properly in large fills or in moist air, and the dielectric strength of uncured RTV is unknown. Proper testing and consideration of curing conditions are essential for ensuring safety.
Futsal1st
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I understand that Dielectric Strength relates to the point where a compound breaks down under electrical load. Please correct me if I have it wrong.

I want to now if an RTV compound (with Dielectric Strength of approx 500 volts/mm) is safe to use across 240v or 415v terminals that are 3-5mm apart.

Do i understand it that if one applies 500v and the RTV gap is 1mm that it would break down and conduct. Lower voltage or larger gap and it would not conduct and therefore be safe?

Very much appreciate any feedback.
 
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500 volt/mm is for a specific gap.
Larger gaps will have much lower breakdown voltages than 500 volt/mm.
500 volt/mm is used mainly to compare the breakdown voltage for diferent materials.

Should be safe, however where safety is concerned, it is best to test at much higher voltage. Maybe 10 times operating voltage.

Word of caution:
Some RTV's cure with contact to moist air.
A large fill may not cure.
I have no idea what Dielectric strength for uncured RTV is.
 
Thanks for the reply.
 

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