How to pass lots of wires through an enclosure wall? - Page 1
Forum section: electronics / projects

author: JamesG-J
author_rank: Contributor
timestamp: October 27, 2020, 06:24:26 pm
content: Hello!I'm working on a project that requires me to connect a bunch of wires through the wall of an enclosure. Right now I'm trying to get 3 sets of 16 wires connected (though ideally it'd be 3 sets of 32).I'm looking for some sort of sealing (around IP63/4, just splash protection) though it doesn't need to be very serious, could even do without. The wires will all go to different locations to control a bunch of solenoid valves (12VDC, 0.5A) so I don't want to use a big multi-conductor cable and cable gland, and I would like the solution to not be permanent (i.e. filling holes with epoxy/silicone).I found these guys on digikey, but they seem really expensive for what I'm trying to do.https://www.digikey.ca/en/products/detail/phoenix-contact/1899427/2525265https://www.digikey.ca/en/products/detail/phoenix-contact/1778124/349040Does anyone know how the pros usually pass lots of wires through enclosures for control systems? It seems like a pretty common situation but I haven't been able to find an elegant solution yet.Any help or ideas would be greatly appreciated!Thanks in advance,James

author: coppercone2
author_rank: Super Contributor
timestamp: October 27, 2020, 06:39:28 pm
content: typically you could use cable glands and drill holes, they need to be tightened individually though, it would bring your price down some what depending on manufacturer you pick, and it could theoretically pass through a crappy compartment since it has a gasket and no conductors. If the gland is a problem because of wire count, you would typically find a cable of the correct conductor count to reduce the gland count to one or at least put multiple cables to reduce the gland count from having to do a whole bunch of wires (you need to be careful tightening and inspecting them). That would be the most reliable method.

author: MosherIV
author_rank: Super Contributor
timestamp: October 27, 2020, 06:59:11 pm
content: QuoteMilitary, areospace and automotive use circular connectors.Just search for circular connectors.Automotive are going to be the cheapest option.

author: Miyuki
author_rank: Frequent Contributor
timestamp: October 27, 2020, 07:07:15 pm
content: Automotive connectorThey are even with high pin count, like thishttps://cy.rsdelivers.com/product/te-connectivity/776163-5/te-connectivity-ampseal-automotive-connector-plug/7266951Or many ones smaller for reasonable prices

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 27, 2020, 07:27:41 pm
content: The pros just use connectors...Or if direct connection, then flexible conduit (Sealtite(TM) and other brands) or various types of cable glands.The basic cable gland is for a single cylindrical cable, just a rubber washer that snugs up on it. You can get multi-hole glands too, and also stackable rectangular kinds e.g. Icotek and others. Most of which are sold through traditional channels i.e. phone up a rep, request a catalog, quote some items, etc...Even if washdown (IP65+) isn't needed, these are often used, just to improve reliability on something that, reasonably speaking, shouldn't ever fail. Controls, test racks, etc. are usually very low production numbers where NRE is a large part of finished cost, and the materials used aren't very important so you might as well choose very good ones.When water isn't around, those pluggable connectors are pretty good yeah, also good old fashioned D-sub connectors, both of the industrial rectangular kind and the traditional DB25 and whatnot.Tim

author: Gregg
author_rank: Super Contributor
timestamp: October 27, 2020, 09:29:34 pm
content: How about a sheet of neoprene or other suitable rubber sandwiched between your enclosure and a bolt on frame? Wires can be routed through holes in the rubber in any order you like. Holes can be made in rubber with brass hobby tubing sharpened with a file but you may have to eject the rubber plug from the tube after each hole; use lots of lube like dish washi9ng soap with this method. I remember doing this type of thing with old school brass ball point pen refills. Another trick to making holes in rubber is to use a standard drill bit, but put the rubber in the freezer to make it harder and use a wood backer block. The rubber sheet could be glued to the enclosure if desired.A step bit would make it easy to drill a suitable hole in the enclosure and to make a fastening frame out of something like aluminum or polycarbonate.

author: coppercone2
author_rank: Super Contributor
timestamp: October 27, 2020, 11:57:35 pm
content: if you sandwich that assembly between two plates with holes and bolts it might cut the mustard as far as being qood, if its just a sheet of rubber dangling with holes in it i would be suspicious. Then it would need to be mounted on brackets so it does not sag. I am not sure how well it would compress

author: thermistor-guy
author_rank: Frequent Contributor
timestamp: October 28, 2020, 01:15:52 am
content: Quote from: JamesG-J on October 27, 2020, 06:24:26 pmNot sure if this suits your application, but in the past I've used D-subminiature port savers e.g.https://www.l-com.com/d-sub-slimline-d-sub-socket-savers-adapters-low-profile-panel-mountableThe port savers mount on the enclosure. Cables plug in from both sides, and can be removed when not needed.

author: geggi1
author_rank: Frequent Contributor
timestamp: October 28, 2020, 08:19:53 am
content: How about using a home made potted feedtrhrough.Use a large cable-gland I would suggest M60 beacuse of the number of cable (48)Make a jig to keep the conductors separated and straight through the gland.Use a very liquid potting compond to pott the gland. 3M got some very good stuff.

author: Haenk
author_rank: Super Contributor
timestamp: October 28, 2020, 10:27:51 am
content: military surplus parts, those connectors are usually waterproof and not very expensiveOr maybe use a Flexstrip-like cable, a bit of silicone and route it right between the halves of the case...

author: cdev
author_rank: Super Contributor
timestamp: October 28, 2020, 01:45:38 pm
content: They have feed-through caps now with built in inductors which make for more more effective RF filtering.They are marketed as RF filters, which although technically true, perhaps isn't where I would look.

author: MarkF
author_rank: Super Contributor
timestamp: October 28, 2020, 02:23:01 pm
content: As said before, circular connectors are typically used in military applications.https://www.mouser.com/ProductDetail/Amphenol-SINE-Systems/RT0W01832SNH?qs=tU8m4arrIN%2FwmAvdSlCBdg%3D%3D

author: JamesG-J
author_rank: Contributor
timestamp: October 28, 2020, 03:24:22 pm
content: Wow, thanks everyone for all the suggestions!!!I was clearly barking up the wrong tree with that panel-mount terminal block! I'm starting to redesign based around some IP rated connectors and bundling sections of the wires using multi-conductor cable, as that's clearly the way to go with this - I'll have to either strip a few feet off the other end or use another small box to break them into their separate pairs and route them to different spots, but that seems worth it considering I'll get a true seal at the control box.Huge thanks again everyone, maybe I'll post some pictures once I get it built!

author: Rx7man
author_rank: Regular Contributor
timestamp: October 29, 2020, 06:26:29 am
content: we used breakout boxes for our larger equipment, we were powering a lot of 24VDC solenoid valves.. we usually ran an 18ga 2 conductor wire to each one from the main panel, but bigger projects we'd run a 9 conductor to a breakout box, especially if it went to something that would have to get disconnected for shipping, etc Each wire passed through a gland, but if you're just looking for splashproof and you have the connections on the bottom of your enclosure, you could probably get away with running a couple wires through a gland

author: JamesG-J
author_rank: Contributor
timestamp: October 29, 2020, 01:10:53 pm
content: Thanks for sharing the photo, Rx7man, that's exactly what I'm trying to build (except I'm trying to reduce costs by staying away from DIN rail stuff) - really helpful to see everything up close!Was that installed at a farm? What was the application, if you don't mind me asking?

author: Rx7man
author_rank: Regular Contributor
timestamp: October 29, 2020, 05:21:12 pm
content: Quote from: JamesG-J on October 29, 2020, 01:10:53 pmThis was from my "previous life" as a packaging equipment technician, machines that make boxes is what I didNowadays instead of $3000 PLC's with $1000 screens you could easily make this with an Arduino for $50, but big corporations want everything integrated and standardized so they pay the big bucks.. I can't remember the exact machine this came from , but here's a video of one (this was probably the most complex I'd worked on)https://youtu.be/mQukx2IyyL0

author: elekorsi
author_rank: Regular Contributor
timestamp: October 29, 2020, 05:25:29 pm
content: It really depends on application, but usually you have several locations where multiple sensors/actuators are located on small area of the machine. Like @Rx7man said, you then put the breakout box on the location and connect it to main cabinet with multi conductor cable.I only have crappy photos of partly finished projects, i allways forget to make photos at the endI attached photos of recently build smaller project (retrofit to an old machine) where majority of signal connections is done via multicore cable (25x1mm2, 12x1mm2).1st picture is the cabinet partially wired. Second picture is on is on site where you can see several multi conductor cables for the signals. Please excuse the mess with the wires, as this is during the installation and testing. Also ignore the missing wire markings as there is a long story behind thisOn the third picture you can see an example of break out box (i call it terminal box), again unfinished (made a picture to note which terminal markings i forgot).

author: Rx7man
author_rank: Regular Contributor
timestamp: October 29, 2020, 06:57:39 pm
content: Quote from: elekorsi on October 29, 2020, 05:25:29 pmthat looks nice and tidey.. but yeah, those wire markers!!!At my shop we had wire marker sticker booklets, but we ran out of many of the numbers that were commonly used.. in the end we got a heat shrink tubing printer that worked really nicely

author: Pack34
author_rank: Frequent Contributor
timestamp: October 29, 2020, 07:43:25 pm
content: I've always liked this style. The TE connectors also come with a heat shrink boot the screws onto the back.https://www.alliedelec.com/product/te-connectivity/206429-1/70083004/

author: S. Petrukhin
author_rank: Super Contributor
timestamp: November 02, 2020, 01:12:49 am
content: Quote from: Rx7man on October 29, 2020, 05:21:12 pmCompanies do not want to save $2 950, having a daily profit many times more and fearing the risk of losing a lot of money due to a bump in a children's toy Arduino.PLC manufacturers take advantage of this and push up the price. Market law.A 12 MB (mega byte) Siemens CD flash is the coolest SSD per gigabyte price.

author: Rx7man
author_rank: Regular Contributor
timestamp: November 02, 2020, 06:39:29 am
content: Quote from: S. Petrukhin on November 02, 2020, 01:12:49 amThe sad part is the internals are probably the same as any flash chip you'd buy, just with a different pinout and fancy connector.. I remember that from Allen Bradley12 years ago I got a 2hp VFD, Allen bradley powerflex 40, was $600 buying through our company which got massive discounts arranged by Pepsicoa month ago I got a 10hp VFD from china for $140.The only problem with Arduino is glitches from programming errors, and ladder logic is certainly not immune to those!

author: Berni
author_rank: Super Contributor
timestamp: November 02, 2020, 06:57:53 am
content: Yep use automotive connectors. They are the cheapest waterproof connectors that still offer many pins and plenty of current handing. They might be plastic but they are certainly very reliable even in harsh enviorments as the automotive industry has really optimized the heck out of them over the many years.PLCs are not just about selling you a overpriced microcontroller. They are selling you robust hardware that is designed to keep working in hot dirty factory enviorments with robust I/O that will not get fried by an occasional voltage spike. They are also selling you into the whole ecosystem of software to go along with it along with other hardware that can easily communicate over the various protocols in a robust way.Yes it is overpriced and the ladder logic makes me cringe, but in the end of the day it gets the job done and keeps getting it done 24/7 all round the year, in factories machine down time is very expensive, more expensive than these PLCs. And when one does break they can just get a new one off the shelf, stick it in, load the software on and away you go. Can be fixed by any competent electrician.

author: geggi1
author_rank: Frequent Contributor
timestamp: November 02, 2020, 09:07:19 am
content: Not all PLCs are overpriced. If you go for the high end stuff you will end up paying a lot, but for simpler automation stuff there are plenty to select from. Have look at brands like Omron, Wago and Beckhoff they have a lot of reasonable priced hardware and in some cases the programming software is also free or are reasonable priced.

author: Jeroen3
author_rank: Super Contributor
timestamp: November 02, 2020, 10:22:19 am
content: Instead of a dozen holes with ferrules you could also go for a "cable entry plate".Which may be easier for production, not for one-offs.They are often used as fire barrier, but I can see there are some ip55/65 rated as well.(icotek)

author: S. Petrukhin
author_rank: Super Contributor
timestamp: November 02, 2020, 11:36:27 am
content: Quote from: Jeroen3 on November 02, 2020, 10:22:19 amYes, such plates with membranes are available, for example, at Hensel.

author: Rx7man
author_rank: Regular Contributor
timestamp: November 02, 2020, 09:06:58 pm
content: Quote from: geggi1 on November 02, 2020, 09:07:19 amTrue, there are affordable PLC's, but some customers spec the one they wantWhat really turned me off from AB is the horrible version compatibility they had in their software, it caused sooo much greif, upgrade one program, have to upgrade 5 others, then 2 more would break and you were chasing your tail, you'd have to have 2 different versions installed, etcFor a company dedicated to "integration" they certainly weren't very good at it themselves