I'm trying to solve a Class II - no earth ground connection - medical device 
problem. I have one complex part that I need to insulate such I can get two 
MOPP's of insulation value and it has to be done through an insulator - I can't 
use creepage or clearance distances to solve the problem.

Has anyone used a coating as an insulating barrier? I don't see a condition 
that allows coatings per se., but on the other hand I see that they talk about 
insulations which form supplementary insulation with a working voltage of 
greater than 71V shall be..... and then goes on to explain that it must be 
multiple layers each capability of ,meeting the dielectric test requirements, 
but it leaves voltages lower than undescribed, and I'm at 24 Vdc.

One part would be painted with a very durable Polane paint which is more a 
backed on plastic than a true paint. If part A is painted it mates via internal 
threads of the shaft and provides an insulation bearer on the surface between 
each part - breaking the conductive path. It also has a dielectric withstand 
test value of about 2.5 kV, and for two MOPP's of insulation I only need 1 kV - 
so test wise it stacks up okay.

I can take advantage of the risk management process and I may be able to use 
risk management to indicate a low risk, but would rather have some precedence 
that others have used for coatings.

If I can't use a coating the design process backs way up, and major effort and 
headaches. Nothing's impossible but this is pretty darn close.


Gary McInturff
Reliability/Compliance Engineer








Esterline Interface Technologies

Featuring
ADVANCED INPUT, MEMTRON, and LRE MEDICAL products



600 W. Wilbur Avenue
Coeur d'Alene, ID  83815-9496
Office:208-635-8306
Cell:  509 868 2279
Toll Free: 800-444-5923 X 1238
[email protected]<mailto:[email protected]>


www.esterline.com/interfacetechnologies<http://www.esterline.com/advancedinput>

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