I am trying to find a way to install a component in an aluminum box. This component comprises a rectangular unit measuring about 80mm by 100mm and a power supply of similar dimensions joined by a 5mm cord.

I do not wish to cut and splice the cord so I'm looking for something like the aperture on an SLR camera but large enough to admit the above described. This could be closed around the cord so as to be both vapor and light tight. What are possible solutions?


closed as unclear what you're asking by Matt Young, Stephen Collings, placeholder, Daniel Grillo, Chetan Bhargava May 30 '14 at 17:39

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  • \$\begingroup\$ you don't have to cut or splice anything. Put them in the box and you're done. Your power supply clearly runs off of batteries. \$\endgroup\$ – HL-SDK May 29 '14 at 15:18
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    \$\begingroup\$ molex.com/molex/products/… nearly any of these will work. \$\endgroup\$ – HL-SDK May 29 '14 at 15:19
  • \$\begingroup\$ I tidied the formatting but it's worth describing what you want to connect and further information. Cable glands typically don't cover that range so you might need to add more info on the enclosure etc and exactly what you're trying to do. \$\endgroup\$ – PeterJ May 29 '14 at 15:26
  • \$\begingroup\$ @HL-SDK Putting batteries in the box might work, as long as they're not lead-acid. Putting those in a sealed box can lead to explosions from the outgassed hydrogen. Fun to see pictures of afterwards! \$\endgroup\$ – Stephen Collings May 29 '14 at 17:01
  • \$\begingroup\$ You should take a step back from what you're imagining this thing will look like and think about what it needs to do. Why on Earth would you use an aperture when a gasket would do the job better? \$\endgroup\$ – Samuel May 30 '14 at 2:06

Theses are called cable glands in much of the world, in the US they're called cable connectors. Here is an exploded diagram from this website.

enter image description here

The "Pressure Dome" squeezes the (incompressible) sealing sleeve so that it deforms and presses against the wire, forming a seal, and simultaneously the pressure fingers squeeze the cable insulation forming a strain relief.

This kind of thing will only work well if the cable is more-or-less round. If it's a "Zip cord" construction, I don't hold out high hopes for the seal being good.

Similar products (usually made of metal rather than plastic, and possibly with high-temperature seals such as silicone rubber) are available to seal against tubing.


If you can't get the cable through the parts, there are "split" types available that snap over the cable.

enter image description here

  • \$\begingroup\$ In my experience, these often fail to even hold a cable. I wouldn't count on vapor tight. \$\endgroup\$ – Scott Seidman May 29 '14 at 17:28
  • \$\begingroup\$ @ScottSeidman The tubing ones work pretty well, the cable gland ones I've had good luck in splash-proof industrial housings when they're sized properly. I think a bit of steam would be okay too. Agreed that if he really needs vacuum-tight sealing, this would be inadequate, and feedthroughs are probably the only way. \$\endgroup\$ – Spehro Pefhany May 29 '14 at 17:30
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    \$\begingroup\$ +1 for cheaper and simpler than my answer \$\endgroup\$ – HL-SDK May 29 '14 at 20:35
  • \$\begingroup\$ Would you be able to find one though with a 100mm diameter that could close down to 5mm? I was looking for one a few months ago I could pass a USB cable assembly through and couldn't find one to cover that smaller difference. \$\endgroup\$ – PeterJ May 29 '14 at 23:11
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    \$\begingroup\$ I'm in the US, and I've never heard them called "Cable Connectors". Huh. Maybe it's regional? \$\endgroup\$ – Connor Wolf May 30 '14 at 3:15

Moisture and vapor barriers are critical when corrosion from humidity can cause dielectric insulation failures. The only reason laptops survive high humidity is the internal heat and air flow, but any fluids getting in from spills will cause certain failure to any unsealed unit. If your only concern is ease of installation with a vapor and light barrier, consider vapor pressure and potential outgassing effects.

If you want to keep the cable in tact, a removable aperture or lid is required. To seal it, consider black neoprene gaskets for the seal with RTV silicone adhesive around the cable. But if you have hydrogen pressure inside from batteries, equalization with blocking moisture requires a teflon insert. Teflon has the molecular properties of permitting only hydrogen to escape under pressure. This may be impossible, if the box and lid is too flexible or leaky.


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