Happy Holidays Group,

Let me set the scene for you:   

We have a piece of laboratory equipment that has a 10,000 volt low current power
supply that puts a high potential onto a small metal sample as it is being
tested.  When the operator opens a door to remove the sample we have to turn off
the high voltage to protect the operator.

We have been looking for a High Voltage Relay to do the job without luck.  We
have found several that are rated for 10,000 volts, but the creepage and
clearance spacing between the pins don't seem to match what the IEC61010-1:2001
standard says.

If I am reading the standard correctly, the creepage is the big problem.  Table
7 calls for a spacing of 40mm on pc cards pollution degree 1.  This seems like a
lot.  The clearance would be 30.3mm  -  31.6mm according to Table 5.  We have
one relay that is rated 10,000 volts, but it only has 23mm between the contact
and the coil pins.  How can this be?  Am I looking at something wrong here?  

I can't find any high voltage relays with any kind of agency approvals.  

1. Am I figuring out the creepage distance correctly or am I missing something?

2. If I do have to meet the spacings listed above, does anyone know of a good
source for a compliant relay?

3.  Anyone have tips and suggestions how to minimize spacings in high voltage
circuits?

Thanks to all.
Brian Kunde
LECO Corp.

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