3500VAC rated 1 Meg resistors for Offline SMPS isolation barrier?

[grizedale]

Hello,

Do you know where I can source high-voltage , low-power 1 MegOhm resistors for paralleling with Y caps, which bridge the primary – to – secondary isolation barrier in an offline SMPS?

These resistors must withstand the 3500VAC HiPot isolation tester.

-Though I cannot find resistors that meet this voltage requirement.

-the purpose of these resistors is to allow leakage current to pass from secondary to primary, in order that the secondary side does not float up to dangerously high voltages.

 

[kak111]

Thick Film, High Voltage, and Precision Resistors
**broken link removed**

http://www.datasheetcatalog.org/datasheet/vishay/rox.pdf

**broken link removed**

High Voltage Resistors and Voltage Dividers

 

[Orson Cart]

Several resistors in series is a good idea in case one fails short (UL safety requirement)

 

[goldsmith]

The power of 1mega ohm resistor at this voltage should be up to 13W. you can use snubber network to obtain your aim.
or higher resistors. but my suggestion to you is an snubber network

 

[Orson Cart]

A hi-pot tested generally cannot supply 13W - it would trip out earlier. This is why several resistors in series (10 x 2Meg2) for example is a preferable idea.