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A research group just bought an electrostatic speaker that came with a long cable that is meant to be soldered to the speaker wires. However it would be more convenient to have a connector(s) there. There are 3 wires (+ shielding): audio negative, audio positive (500V peak to peak) and bias voltage (450V). Given the high voltage (but low currents 0.25A), I'm not sure what connector would be appropriate. I doubt typical audio connectors would be rated for 500V. I'd also prefer something that locks and cannot be touched. I was thinking XLR because of phantom power, but I couldn't really find specific voltage ratings... Any suggestions, references, comments?

Edit: Manufacturer said anything rated for 115 W is more than enough. (I added the max current for the speaker above.) I learned about Paschen's Law (for spark risk in air) and calculated that I'm ok with pins spaced by 0.1 mm or more. Whatever insulation is used in the connector, I assume it's at least as good as air... But I'd still rather use something rated for 450V if someone has a suggestion.

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  • \$\begingroup\$ XLR is not appropriate. Phantom power is typically 48V. This page: cpc.farnell.com/1/1/4383-xlr-plug-3-pin-701-0300-deltron.html gavies a voltage rating of 250V for an XLR plug. \$\endgroup\$
    – DoxyLover
    Mar 9, 2015 at 22:50
  • \$\begingroup\$ @Doxy but with 16A, that's 4kW, so fine according to manufacturer, regarding heating risks at least. And with proof voltage at 1.5kV, I'd tend to agree it's probably fine for shorting as well. Are there other risks I'm not thinking of? \$\endgroup\$
    – zorgkang
    Mar 10, 2015 at 15:40
  • \$\begingroup\$ I did not notice the "proof voltage" entry. Sorry. It does specify a working voltage of 250V. One other worry I'd have is that the typical XLR cable is probably not rated for your voltages. You will need to make custom cables and make sure no one tries to use an off-the-shelf cable. \$\endgroup\$
    – DoxyLover
    Mar 10, 2015 at 17:47
  • \$\begingroup\$ I would use nothing that had anything to do with audio, to save the risk of false assumptions by users. \$\endgroup\$
    – user207421
    Mar 10, 2015 at 18:44
  • \$\begingroup\$ I already have the cable for the speaker, and I was planning on having large warning labels or tags on both connectors since it should not be plugged or unplugged while the amp is on. But even then, if I used XLR, as @EJP points out there would be the risk of users using another cable as an extension for example, so I'll steer clear of audio. Back to square one. \$\endgroup\$
    – zorgkang
    Mar 10, 2015 at 21:04

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Phantom power, as I understand it, runs at about 48VDC, max, and XLRs aren't rated to stand off 500 volts, so that's not a viable solution.

If you need frequent connection and disconnection, my druthers would be to opt for terminal blocks on the speakers which would accept the stripped and twisted ends of the cables.

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  • \$\begingroup\$ Unfortunately, because of various factors (including location and users) I feel I need a safer and more fool-proof solution. Might be ok if somehow hidden inside a box though, so keeping that option in mind. \$\endgroup\$
    – zorgkang
    Mar 10, 2015 at 2:47

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