I need to pass three wires, about 24 AWG through a panel into a waterproof enclosure.
I see this connector pair: but it's 10A which is really over-kill. I don't really need a connectorized solution so I could pass the wires through the panel if there were a good way to seal the hole.
If the wires are insulated, sheathed, and in a basically round cable, the solution is a weathertight packing gland, like
If it really has to be a single seal for three loose wires, maybe you could get by with a bit of roofing tar...
If you don't need them to move, or be removable, potting compound should do the job. On the low end , silicome RTV (aka more or less normal silicone caulk) can work if it's not abused. Other materials may work better depending on the particular circumstances - various epoxy products in various degrees of rigidity or lack therof, silicones that are runnier when poured and then harden, good old fashioned pitch, hot glue...
Multistep approaches where a glob of non hardening silicone grease is encapsulated with the wire inside a larger block of a harder compound is a more complicated, but still quite do-able approach.
There are also purely mechanical and removable pass-throughs (aka "cable glands") which can be tightened to compress an O-ring around a wire or rod.
Be sure to deal with mechanical strain relief.
-- Cats, coffee, chocolate...vices to live by Please don't feed the trolls. Killfile and ignore them so they will go away.
Does it have to be pressure tight? If so, what differential pressure? Hint: Heating a sealed cabinet will increase the air pressure inside. However, when it cools down, the partial vacuum will suck water into the cabinet. IP67 is good for temporary immersion down to 1 meter (1.4 PSI). IP68 is the same except long term immersion. IP69 is the same except that it has to also survive high pressure water jets.
That looks like an M14-3 connector but I'm not sure. M10 size only comes in M10-2 so that's out.
M12 is rated at 2A to 6A. You might find a 4 pin more common than a 3 pin: I couldn't find a feed through, so I guess a panel mount and mating plug might be an alternative.
M8 is possible, but might be too small.
Note: These are not cheap.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On Tue, 30 Jun 2015 18:43:16 -0700 (PDT), whit3rd Gave us:
Anything single strand can "break free" from the sealant usually from flexure. on either side.
Teflon is water tight, but generally adheres to next to nothing. Being inside a jacket fails too because then the jacket ends need to be sealed. So any soft sealant would fail. Hard epoxy and polyurethanes do pretty good if the poly is 'turgid' enough.
Surprisingly, simple transformer varnish works if enough gets applied and the gaps are small.
Also as a note, none of this works at great depths. 10 feet max is typical without pro level sealing methodologies being incorporated.
Waterproof or weatherproof? I.e., "through a panel from outdoors to indoors" is different from "through a panel into panel at bottom of swimming pool"!
If just weatherproof (i.e., no pressure differential), you can typically shelter the actual entry points into the enclosure (from direct "blown water") using silicone sealant around the wires and a "drip loop" just outside the enclosure.
Likewise, you can use rubber grommets (at most one per conductor) with undersized I.D.'s.
Don Y wrote in news:mmvpf3$let$ snipped-for-privacy@speranza.aioe.org:
If you pass a stranded wire or a multiconductor cable through a panel, no matter what gland you use, there are always voids between strands or between wires which water can wick through (even uphill) by capillary action so it it is only as waterproof if the rest of the cable's insulation and the far end of the cable are absolutely perfectly waterproof.
If you need better than that, you need solid metal pins hermetically sealed in a connector body or ceramic feedthrough. Obviously, where the wires connect to the exterior pins has to be waterproofed as well, but a leak there will only compromise the wire, not the whole enclosure, so a simple gland and maybe potting or packing with silicone dialectric grease will usually be adequate. If you go down this route without a connector, consider the difficulty of replacing a failed cable - if its potted the whole unit had better be cheap enough to treat as disposable.
-- Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED) ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL
I trying a vacuum tight connector that uses a pcb for the vacuum seal. Solder seal on the connector feed through, (both electrical contact and vacuum seal.) With an o-ring groove milled into the "panel". I'm not sure if that would work for you... it certainly doesn't keep water off the outside of the connector. (I haven't actually tested this yet.)
George H.
Perhaps an insulated feed through terminal (threaded or push in)?
Or, maybe something like these?
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
That's why you use individual grommets. Each "cylinder" (individual conductor or jacketed *group* of conductors) needs to be sealed. I prefer using silicone for multiple wires as you can work the sealant between the individual conductors, effectively providing a single hole through the goo for each. You could possibly do the same with a
*single* rubber grommet (esp for such small wire diameter) if you could carefully punch a series of non-overlapping holes through the grommet material and individually thread the conductors through their respective holes. I'd be leary of the grommet tearing in the process, though. [The OP hasn't clarified his intended application, quantity, etc.]Silicone sealant has worked well, here, as we have *lots* of conductors exiting the confines of the house (irrigation, lighting, sensors, etc.). It's a mess to undo -- but most of the places where we've used it aren't intended to be "serviced". Similar to conformal coating boards and treating them as largely disposable/unserviceable. Wire is cheap -- just make sure you include a decent service loop from which to salvage wire when/if the cable (passthru) has to be cut.
Failing to include a drip loop can result in water ponding around the connection or point as which the cable passes through the wall of the enclosure (which, over time, can corrode that surface).
If outdoors, you also have to consider the effect of UV on the insulators and sealant. Here, outdoor cables don't fare well if left unpainted, unburied, etc.
For splices (and other wire-to-wire connections), the actual metallic conductor has to also be "potted" lest moisture wick under the insulation. Note that this moisture can come from things as subtle as condensation (e.g., morning dew) so actual location and orientation won't help.
I've found placing the spliced wires in a small plastic container (my favorite is old Rx bottles) and then filling the container with silicone. This ensures no moisture gets at the conductors, provides for some additional mechanical strength at the splice *and* makes the splices much easier to later locate (e.g., for below grade routes).
I think the cable glands will work, maybe with some grease or sealant.
There will be no immersion and no direct spray, just indirect spray. I may even put a hole in the bottom of the enclosure for drainage.
The big issue is that these enclosures are going to have to be opened about every two months for battery replacement, if my power consumption calculations are correct. I lobbied for higher-capacity rechargeable batteries with the option of a water powered generator but that's not happening in this iteration.
Why would you need drainage??? If there is anything to drain, you have real problems and the enclosure is not doing much good.
Water powered??? Is this from a tap or natural source? What is the power consumption rate? Any chance of photovoltaic? What about thermoelectric?
-- Rick
I remember a rocket launcher many years ago, we could not keep the 240 volt rotation control from taking in water no matter how much silicone sealing was done. Solution was to leave a bolt out of bottom to let any water just drain away :-Z
-- John G Sydney.
How about a rubber test tube stopper, with 3 holes (laser) drilled for the wires? Seal the wires to the stopper with RTV.
Give up on that now, while you're still sane. If you have to pass any kind of water spray test on a grease sealed enclosure, you're going to have water incursion. If the pressure doesn't deform the seal to let the water in, the partial vacuum created by the cold water hitting the (NEMA?) enclosure will suck the water in. Since you probably don't want to pressurize the case to prevent water from entering, you'll need to provide an exit path for any water that sneaks past your seals. That usually means an open drain at the bottom of the box.
Incidentally, that also means that your PCB's will need to be mounted vertically. Horizontal boards puddle water. However, if you must have horizontal boards, perforate the PCB with drainage holes.
Oh-oh. You didn't specify the battery type, but many batteries outgass corrosive vapors. If you put a VRLA battery in a sealed enclosure with some electronics, you'll have corroded electronics almost immediately. The battery is usually installed in a seperate compartment that is very well vented. Something like this: For large batteries, the vents have to be large enough to prevent the acumulated vapors from producing a NEMA fragmentation bomb. Notice that I said vents, not vent. You need both an intake and an exhaust vent or you won't have convective air flow.
Well, if you are NOT charging the batteries, then you probably will not need to worry about outgassing. That only happens when the battery is being charged. However, all bets are off if the enclosure gets hot, which might cause the battery to outgass.
The way I tested this was to put a clear airtight plastic bag over the battery and overcharge it. The condensed electrolyte was visible on the bag.
Cool. I've never seen a waterfall inside a NEMA box.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.