Getting USB cable through cable gland - Page 1
Forum section: electronics / projects

author: DanielRehak
author_rank: Contributor
timestamp: August 27, 2024, 02:43:47 pm
content: Hello,at the moment I face a problem where I need to run USB cable through cable gland similar to picture below. First of all I need the cable to be be according to USB 3.2 Gen1 specification (formerly known as USB 3.0, speed 5 Gbit/sec). I would like to avoid cutting connector off, then passing cable through cable hole and then reattaching connector - as I understand this is not something you can do without professional machines for USB 3.2 Gen1 cable.USB cable has USB-A male connector from both sides. I have trouble guiding USB-A connector through inner gasket of cable glands - gasket is too small for connector. If I use bigger cable gland with bigger gasket diameter, then the gasket is too big for cable diameter.I cannot use cable gland with split gasket as well. By split gasket I mean gasket which is split in one section, see image below.The reason is because I need cable gland to have one particular certification. And cable gland with split gasket which has such a certification does not exist. Cable glands without inner gasket which use filling compound instead all seems to have a similar issue - you cannot get the connector part through the cable gland and at the same part end up with cable diameter bigger than minimum allowed cable diameter.I also tried finding USB extender via CAT 5E or CAT 6 cable such as this onehttps://www.amazon.com/Monoprice-Extender-CAT5E-Connection-150ft/dp/B003L14ZTCmain issue with this is that there is simply no USB 3.2 Gen1 version that would not be big, high power consumption and expensive. If I found one it would be very simple because crimping CAT5 / 6 cable is something anyone can do with simple tools.So it appears all roads lead to cutting off USB wire, passing it through cable gland and then resoldering cable ends back together.Now I would like to ask:Do you have any tips on how to solve this other than soldering USB cables?Do you have any experience with soldering USB 3.2 Gen1 cables? I am interested mainly in how to reconnect all the shields so the cable is as robust as it can be to EMC.Cheers,Dan

author: themadhippy
author_rank: Super Contributor
timestamp: August 27, 2024, 02:51:53 pm
content: use a bigger gland and fill it with silicone or would a usb bulkhead connector work?

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 27, 2024, 02:54:27 pm
content: considered these USB integrated circular connectors?look for it, various companies make similar products.https://www.amphenolltw.com/product-info/USB/TypeA3.2Gen1/?

author: DanielRehak
author_rank: Contributor
timestamp: August 27, 2024, 02:58:01 pm
content: I need it to pass ATEX directive. It says the device is safe to use in areas with explosion risk. In this certification it is very good for you to use cable glands which are already ATEX certified by cable glands manufacturer. And I did not manage to find any fillable cable glands which meets following requirements:1] connetor can be passed through2] cable diameter >= minimal cable diameter found in datasheet

author: DanielRehak
author_rank: Contributor
timestamp: August 27, 2024, 03:00:20 pm
content: Yes, we did.Problem is there does not exist a variant with ATEX certification which support USB 5Gbit/sec.Amphenol makes only 1 variant which is only USB 2.0 compatible which is too slow for my application.Otherwise this would have been a perfect solution.

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 27, 2024, 03:09:23 pm
content: hmmm.... necessarily have to use a USB connector to make the connection?What about using ATEX compliant circular connectors and soldering/crimping the USB connector?Seems better than cutting and passing a cabe gland.Or can get a cable and USB connector and make your own. There should be a male female connector for soldering.

author: DanielRehak
author_rank: Contributor
timestamp: August 27, 2024, 03:18:12 pm
content: Quote from: squadchannel on August 27, 2024, 03:09:23 pmThe information must be passed over USB protocol as the device does not support any other bus. Most suited for that is USB cable but I suppose CAT 6 cable could also work.Quote from: squadchannel on August 27, 2024, 03:09:23 pmYou would need to buy a cable with male circular connector. Those cables are never twisted pair and dont have the shielding that USB 3.2 Gen2 cables use. I doubt it would work.Quote from: squadchannel on August 27, 2024, 03:09:23 pmThis would be good but I dont think there are any DIY USB 3.2 Gen1 crimping kits. It appears you need professional tools and machines for that.

author: voltsandjolts
author_rank: Unknown
timestamp: August 27, 2024, 03:35:20 pm
content: You need to be very careful due to ATEX certification requirements.Some ATEX rated devices have communication interfaces which are only to be used in a safe area, e.g. for configuration before deployment, or data transfer after deployment.I suggest you take professional advice from someone with ATEX engineering experience before deploying anything in a potentially explosive atmosphere. Perhaps you have already done that.Edit:Beware that it is the combination of gland AND cable which make for a safe entry, with a pressure rated explosion pressure containment. You can't fit a random cable to a certified gland and call it safe. You must abide by gland manufacturer guidelines for cables.

author: DanielRehak
author_rank: Contributor
timestamp: August 27, 2024, 03:48:54 pm
content: Quote from: squadchannel on August 27, 2024, 03:09:23 pmThe picture looks interesting. Maybe the solution will be easier then I first thought. Before I was looking only at USB-C and didnt realize you could crimp USB-A. Do you have any experience with soldering and crimping this? I dont know if there are some crimping pliers for this that can be bought.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 27, 2024, 03:55:51 pm
content: Could you stretch the grommet over a USB-C plug? Maybe with the plastic overmoulding stripped off?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 27, 2024, 03:58:06 pm
content: If the plug will fit through the panel hole, maybe talk to a cable assembler about supplying cables with the gland already fitted as part of their assembly process

author: DanielRehak
author_rank: Contributor
timestamp: August 27, 2024, 03:59:26 pm
content: Quote from: voltsandjolts on August 27, 2024, 03:35:20 pmOK but I need data transfer even after deployment, so this does not help.Quote from: voltsandjolts on August 27, 2024, 03:35:20 pmThis is development phase, nothing is deployed. I would go to jail if I deployed any product without ATEX certification into ATEX zones. I have read all the norms and consult with institutions which are responsible for ATEX certification in my country.

author: langwadt
author_rank: Super Contributor
timestamp: August 27, 2024, 03:59:34 pm
content: https://buttkereit.co.uk/news/atex-certified-cable-entry

author: DanielRehak
author_rank: Contributor
timestamp: August 27, 2024, 04:05:43 pm
content: Quote from: mikeselectricstuff on August 27, 2024, 03:55:51 pmThis can be done but you risk stretching the grommet so much it will no longer seal properly. You would need to find a grommet that fulfills following:1) maximum cable diameter that can fit inside grommet >= maximum USB connector width2) minimum cable diameter that can fit inside grommet <= USB cable diameterAnd there does not exist anything like that.

author: DanielRehak
author_rank: Contributor
timestamp: August 27, 2024, 04:06:27 pm
content: Quote from: mikeselectricstuff on August 27, 2024, 03:58:06 pmThat is good idea, will try that, thank you!

author: voltsandjolts
author_rank: Unknown
timestamp: August 27, 2024, 04:07:19 pm
content: https://www.mouser.co.uk/new/amphenol/amphenol-pcd-usbftvx-atex-connectors/?srsltid=AfmBOoqUQ-w8mp_KX6o6PhzyUyE3q222iCnPVpHCnl6VlgkNs_NZb1vu

author: DanielRehak
author_rank: Contributor
timestamp: August 27, 2024, 04:09:27 pm
content: Quote from: langwadt on August 27, 2024, 03:59:34 pmI know these but their certification is "too weak" to make them usable in our application.

author: DanielRehak
author_rank: Contributor
timestamp: August 27, 2024, 04:11:52 pm
content: Quote from: voltsandjolts on August 27, 2024, 04:07:19 pmThats USB 2.0, not usable.

author: voltsandjolts
author_rank: Unknown
timestamp: August 27, 2024, 04:45:51 pm
content: Go fibre? ATEX connector solutions for fibre arecommercially available.

author: rteodor
author_rank: Frequent Contributor
timestamp: August 27, 2024, 05:56:25 pm
content: Can you go with PG25 and use certified tube or pipe ?And/or maybe use USB-A to USB-C adapters of some sort ?I could pass an USB-C connector on a PG9 gasket but it needs just a few mm for the gland parts. The USB-C connector is about 10mm wide, it should go thru PG13 with ease.

author: DanielRehak
author_rank: Contributor
timestamp: August 28, 2024, 03:29:20 pm
content: Quote from: voltsandjolts on August 27, 2024, 04:45:51 pmWould be good. Do you know of some way to convert USB into optical fiber easily? Would have to be some compact solution.

author: DanielRehak
author_rank: Contributor
timestamp: August 28, 2024, 03:30:30 pm
content: Quote from: rteodor on August 27, 2024, 05:56:25 pmUnfortunately this solution is not suitable for our solution. Thank you for suggestion though!

author: voltsandjolts
author_rank: Unknown
timestamp: August 28, 2024, 04:10:05 pm
content: Quote from: DanielRehak on August 28, 2024, 03:29:20 pmhttps://www.lindy.co.uk/usb-c4/200m-fibre-optic-usb-3-0-extender-p9144...and others

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 28, 2024, 05:23:34 pm
content: Quote from: DanielRehak on August 27, 2024, 04:05:43 pmWarm it up if necessary. Max specced dia when used in the gland isn't the same as what you can stretch it to when taken out of the gland.

author: DanielRehak
author_rank: Contributor
timestamp: August 29, 2024, 09:28:14 am
content: Quote from: voltsandjolts on August 28, 2024, 04:10:05 pmThis looks interesting. It is definitely the smallest one i ever saw. But its pretty expensive and mainly it needs 5V 3A power supply which could be solved but would be high effort.For now I decided to buy USB 3.0 male header and solder it back onto cable after cutting and passing it through cable gland.

author: DanielRehak
author_rank: Contributor
timestamp: August 29, 2024, 09:30:10 am
content: Quote from: mikeselectricstuff on August 28, 2024, 05:23:34 pmOk this is a new one for me. Best next step is to check with ATEX certification organ and Cable gland manufacturers to confirm this would be OK to do so.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: August 29, 2024, 10:20:15 am
content: I would probably cut of the plug, feed the cable through, and then use some non standard connector or soldering inside the box.But there are also USB connectors made for manual assembly as the picture shown by quadchannel. I had to frown my eyebrow for a moment to see how it works, but the plastic insert is shown rotated 180 degrees. The tin plated tabs is where you solder on the wires inside the plug.Maybe it is an option to cut of the plug on the other side and then feed through the whole cable?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 29, 2024, 11:15:30 am
content: For production, another option could be to have the inside-box end be a JST or similar, and get a cable with the contact pins crimped but not clicked into the shell, so the crimped ends can pass through the gland, and the shell put on afterwards.

author: 5U4GB
author_rank: Super Contributor
timestamp: August 29, 2024, 01:54:34 pm
content: Quote from: DanielRehak on August 29, 2024, 09:28:14 amIf you don't mind getting it from a crapvendor you can getbump-in-the-stack onesfor a lot less, USB connectors at the ends, fibre in between. You can also get ones with SFP ports so you can add whatever fibre link you want but they cost a bit more.

author: _Wim_
author_rank: Super Contributor
timestamp: September 01, 2024, 09:34:25 am
content: This company make 2 part cable glands that are Ex certified:https://www.roxtec.com/us/our-products/solutions/?filters=49193We use the non Ex version often at work, nice quality products.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: September 01, 2024, 09:50:17 am
content: Is it an option to replace such glands with some kind of polymerizing caulk? (Silicone or polymer based)1. Put the cable though.2. Fill the hole with caulk3. Let it dry.4. Mount the nut to put some pressure on the caulk so it seals.I guess you have to deal with all kinds of regulations when you have to design for an explosion proof environment.

author: DanielRehak
author_rank: Contributor
timestamp: September 04, 2024, 12:10:55 pm
content: Quote from: _Wim_ on September 01, 2024, 09:34:25 amThis looks pretty interesting, thank you for the tip. I will contact this company.

author: DanielRehak
author_rank: Contributor
timestamp: September 04, 2024, 12:12:51 pm
content: Quote from: Doctorandus_P on September 01, 2024, 09:50:17 amIt is, but all such certified devices assume you strip the outer cable coat and fill the caulk only into inner wires, which is good for standard 230V cable but not for USB cable.

author: DanielRehak
author_rank: Contributor
timestamp: September 04, 2024, 12:16:09 pm
content: Quote from: Doctorandus_P on August 29, 2024, 10:20:15 amBest solution is to buy and solder USB 3.0 header such as thishttps://ninigi.com/cz/cz/product/ninigi/usb-ieee1394-connectors/usba-w3.0/usba-w3-0/100379/It works great.