# How are wires secured into electrical applicance/product?

#### dl324

Joined Mar 30, 2015
14,318
From data sheet, it seems for part (QFG-16200) the hole size is 10mm if you look at top right entry for that part.
I didn't look at that table, but hole side for the part number you gave is 10mm. I have no idea why they started putting metric dimensions in brackets while the ones on the left are in inches.

Joined Jul 18, 2013
25,010
Thanks. From data sheet, it seems for part (QFG-16200) the hole size is 10mm if you look at top right entry for that part.
That part in itself does not offer good retention, there is usually plus some other means such as the saddle etc I showed.
The grommet type typically offers prevention of damage due to flexing only.

#### MisterBill2

Joined Jan 23, 2018
11,605
The usual method is press in. For the part you referenced, hole size is either 18mm or 25mm.
Often a small bit of lubricant on the sliding surfaces makes inserting the grommet a lot easier. A small drop of liquid soap is a good lubricant.

Joined Jul 18, 2013
25,010
Thanks. From data sheet, it seems for part (QFG-16200) the hole size is 10mm if you look at top right entry for that part.
If using that solely for strain relief, I would be tempted to add some RTV silicone to help secure the flex to the grommet.

#### jai.whitey

Joined Oct 19, 2021
16
Can someone recommend a good grommet for this product? https://www.digikey.com/en/products/detail/tri-mag-llc/L6R12-180/7681522

As you can see, the grommet hole has to clear the 10mm barrel jack diameter but after that it's a typical thin wire. I'm looking for a flexible grommet I guess that would allow clearance of the 10mm diameter but is otherwise small.

Joined Jan 15, 2015
6,532
Can someone recommend a good grommet for this product? https://www.digikey.com/en/products/detail/tri-mag-llc/L6R12-180/7681522

As you can see, the grommet hole has to clear the 10mm barrel jack diameter but after that it's a typical thin wire. I'm looking for a flexible grommet I guess that would allow clearance of the 10mm diameter but is otherwise small.
You linked to a common wall wart using a common barrel jack. DC output, standard 5.5 x 2.1 x 9.5mm corded dc output plug right off the data sheet. Just use a mating connector like these or just use a bulkhead connector. If you want to use a grommet just look at your cable diameter and find a suitable grommet. These are among the most common DC connectors out there.

Ron

#### jai.whitey

Joined Oct 19, 2021
16
You linked to a common wall wart using a common barrel jack. DC output, standard 5.5 x 2.1 x 9.5mm corded dc output plug right off the data sheet. Just use a mating connector like these or just use a bulkhead connector. If you want to use a grommet just look at your cable diameter and find a suitable grommet. These are among the most common DC connectors out there.

Ron
Thanks for the reply. I'm using the wall wart with this power barrel jack connector on my PCB (https://www.digikey.com/en/products/detail/cui-devices/PJ-036AH-SMT-TR/1530971). So I still have to feed the wall wart wire into my product to the PCB, so I will need a grommet I believe.

For the grommet, it's a bit tricky since the hole has to clear the 10mm barrel jack diameter at the tip, but the rest of the wire is the typical thin wire. I believe a product such as this one would work: https://www.amazon.com/HYCC-2-3-Fle...a2907&pd_rd_wg=mHcdi&pd_rd_i=B01HT2VKN2&psc=1

#### panic mode

Joined Oct 10, 2011
2,112
it all depends on application. this means considering type of wire/cable (solid or flexible), bending radius, environment/seal rating etc.

a good strain relief grip cable, provides seal, protects cable from sharp edge or flexing at one point.

these types are very low cost and easy to use. just drill a hole and attach strain relief. price per entry can be $1-$10 depending if plastic or metal.

Last edited:

#### djsfantasi

Joined Apr 11, 2010
8,258
Or have you considered removing the jack from the PCB and replacing it with one on the exterior? Then, you can wire it to the PCB with wire and a connector.

#### panic mode

Joined Oct 10, 2011
2,112
when there is plenty of cables to pass through enclosure wall, or if there is an issue preventing cutting/reassembly of cables, there are entry systems that handle that too:

#### Ian0

Joined Aug 7, 2020
4,865
The law requires that the cable must not pull out if subjected to a force of 60N.
My method of testing is to put a piece of tape in contrasting colour around the cable where it enters the product. The attach a weight to the plug (a bag of ball bearings), then use the product to lift the cable and weight off the ground.
Repeat the number of times required by the standard, then look at the tape to see if it has moved.

#### MisterBill2

Joined Jan 23, 2018
11,605
Or have you considered removing the jack from the PCB and replacing it with one on the exterior? Then, you can wire it to the PCB with wire and a connector.
I wish that they would do that with laptop computers. When the power connector is just soldered to the mother board, possibly surface mount only, but even thru-hole is poor, one bump on the power connector and a solder joint fails and becomes intermittent at best. And getting at the area to service on that one HP computer was 23 pages of dis-assembly instructions and 24 pages to put it back together.