D-Sub connectors for high voltage?

Nov 16, 2011 10 Replies

Are D-Sub connectors suitable for carrying multiple lines of low-current 230V AC? The idea is to connect up to 10 individually controlled loads over a 50-foot multi-core cable. The wires are rated for the voltage. Current levels are sub-100mA.



The cable is to be used only 2 or 3 times a year for a couple of days on each occasion, to be dismantled and stored in between each use. On three previous occasions, I used a bundle of twin wires with individual male plugs at one end and a box with a row of females at the other, but I'd like to make the whole thing less bulky and fiddly. (As I've occasionally mentioned in s.e.d., I'm in a place where it's not a simple matter of choosing a suitable connector from an online list and ordering it).



I don't know if there's a universal standard voltage rating for D-Subs. I've seen one manufacturer's specs of 1000Megs minimum at



500VDC and dielectric strength of 1000V AC for 1 minute. To keep things simple, forget about mechanical reliability. I have good soldering experience and could cover each soldered pin with heatshrink, clamp the wires and provide strain relief. I'm sure D-Sub connectors will be fine initially, but I'm wondering about the long-term since they are normally used at much lower voltages.

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They publish a great deal of useful information at their website, plus they even publish third party 'connector resistance' measurements, which I've not found at other connector manufacturer websites..

I've used them at 500 volts, no problems. The clearances are huge on those old klunkers.

John

There is not the creepage distance (less than 1.5mm?) to meet safety standards used in most developed countries, particularly when it gets dirty ("pollution" in the IEC standards).

My unconsidered opinion (which you should not rely upon) is that it will probably be okay from an electrical pov, but you should pay some attention to the safety aspects, such as fusing the lines so that the current rating of the pin (3A or whatever) and the wire going to it cannot be exceeded, and also make sure that nobody can get shocked. Higher voltages are actually better from a conductivity pov, since it will break through oxide layers. They are not better from a safety and a corrosion pov (ie. if the connector were to get wet and power was applied). At less than a volt, nothing much will happen, at 5V, bad things will eventually happen, but slowly, at 230VAC with dirty water, bad things can happen pretty fast.

I couldn't access the site. I'll try again later.

You can get "mixed signal" D-connectors, with fewer pins and holes for bigger connectors, like high currents pins or co-ax inserts. The Farnell catalogue devotes a page to parts from FDI and Harting. Not all that cheap, but sometimes very handy.

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erbinder/

-- Bill Sloman, Nijmegen

You still have the problem of (creepage) distance from pin to shield/ground. That's still < .100", IIRC.

Pimpon has mentioned before that he hasn't easy access to a wide line of products, and is asking about "making do".

If one wants to go with Harting, these connectors are frequently used for temporary connections to plastic molds (eg. hot runners) and would be a good choice if one doesn't need military style connectors and have little in the way of space/weight concerns :

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They're rugged multiple-contact connectors properly rated and safety-agency-tested for mains applications. Not particularly cheap.

Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

Don't do it, because someone will plug it into the back of your computer.

Pick almost any other kind of connector for 230VAC.

Good Luck! Rich

nd.

Instruct user to keep the connectors perfectly clean and dry, as surface contamination could cause a rapid breakdown. Fuse each line to cut power in case of short, using of course a very thin strand of cu.

This sort of thing wouldnt be acceptable in the west, but yes it works.

NT

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