How are wires secured into electrical applicance/product?

Thread Starter

jai.whitey

Joined Oct 19, 2021
16
Hello - please forgive this novice question. How are wires secured from the outside into electrical appliances/products? It doesn't seem as simple as creating a hole the same diameter as the input power wire. See the attached photo for an example of a fan. It seems there is some type of heat shrinking going on? I'm just curious how to secure a wire inside a product so it doesn't become loose, or when you pull on a wire it doesn't pull on the internal PCB. Hope I'm making sense here.
 

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dl324

Joined Mar 30, 2015
14,317
I'm just curious how to secure a wire inside a product so it doesn't become loose, or when you pull on a wire it doesn't pull on the internal PCB.
There are multiple methods that can be used. The photo you posted looks like could be a grommet that protects wire insulation from sharp edges (the cord could also be tied in a knot on the inside to prevent it from being pulled out).
1638508980930.png

Another option is something like this that includes strain relief:
1638508873780.png
 

MaxHeadRoom

Joined Jul 18, 2013
24,999
Generally some form of strain relief component or method is used, the wire insulation itself is sometimes bonded to the relief device. Implemented by the manufacturer.
 

Audioguru again

Joined Oct 21, 2019
4,532
Some cheap electrical products sneak through the border without passing a safety check and have their power cable secured with a bit of chewing gum.
 

Reloadron

Joined Jan 15, 2015
6,527
Your example reflects the use of a rubber grommet exactly as dl324 shows in his post. Next as MaxHeadRoom points out many applications require a form of strain relief. I believe you will find if you research "through the bulkhead" connectors they are chosen for their intended applications. Endless variables figure into things like running a wire through a chassis hole. Water proof? Water resistant? Environment and the list goes on. The method is chosen based on the application. :)

Ron
 

MaxHeadRoom

Joined Jul 18, 2013
24,999
I have at least a couple of small appliances which either have a small non-restraining grommet but internally there is a U shaped screw-clamp.
On another no grommet at all but just the U-clamp.
 

MisterBill2

Joined Jan 23, 2018
11,593
Your example reflects the use of a rubber grommet exactly as dl324 shows in his post. Next as MaxHeadRoom points out many applications require a form of strain relief. I believe you will find if you research "through the bulkhead" connectors they are chosen for their intended applications. Endless variables figure into things like running a wire through a chassis hole. Water proof? Water resistant? Environment and the list goes on. The method is chosen based on the application. :)

Ron
A grommet is protection from insulation cutting and is not intended to provide any train relief at all.
Many better products have an arrangement in the plastic housing that provides a repairable strain relief. Some products have a molded on grommet equivalent. Many premium products have a power inlet connector well anchored, and an unpluggable cordset,
 

Reloadron

Joined Jan 15, 2015
6,527
A grommet is protection from insulation cutting and is not intended to provide any train relief at all.
Many better products have an arrangement in the plastic housing that provides a repairable strain relief. Some products have a molded on grommet equivalent. Many premium products have a power inlet connector well anchored, and an unpluggable cordset,
Really, now show me in the quote of what I posted I said a grommet provided strain relief?
Your example reflects the use of a rubber grommet exactly as dl324 shows in his post. Next as MaxHeadRoom points out many applications require a form of strain relief. I believe you will find if you research "through the bulkhead" connectors they are chosen for their intended applications. Endless variables figure into things like running a wire through a chassis hole. Water proof? Water resistant? Environment and the list goes on. The method is chosen based on the application. :)

Ron
Get it right when you quote me and don't mix words. I never claimed or said a grommet afforded strain relief. Maybe if you actually read rather than skim what others post you would get a clue. Incidentally it is strain relief, I have no clue what train relief is unless it's a train relieving itself?

Thank You and Have a Nice Evening
Ron
 

MisterBill2

Joined Jan 23, 2018
11,593
Really, now show me in the quote of what I posted I said a grommet provided strain relief?


Get it right when you quote me and don't mix words. I never claimed or said a grommet afforded strain relief. Maybe if you actually read rather than skim what others post you would get a clue. Incidentally it is strain relief, I have no clue what train relief is unless it's a train relieving itself?

Thank You and Have a Nice Evening
Ron
OK, and My comment was because the picture of a grommet was immediately after the question about strain relief, and so regardless of how specific you were, some folks do not get what the words mean. My comment was never intended to challenge what you said, and no, it was just clarifying what you did not say.

So it was not to be critical, it was to clarify because some folks will not understand the difference. I certainly did not intend any offense.
 

Reloadron

Joined Jan 15, 2015
6,527
OK, and My comment was because the picture of a grommet was immediately after the question about strain relief, and so regardless of how specific you were, some folks do not get what the words mean. My comment was never intended to challenge what you said, and no, it was just clarifying what you did not say.

So it was not to be critical, it was to clarify because some folks will not understand the difference. I certainly did not intend any offense.
OK, forget it. No big deal. I took a chill pill AKA bottle of cider.

Ron
 

MrSalts

Joined Apr 2, 2020
1,551
You can buy cables with over-molded strain relief and cord grips.
Here is one for a 12VDC barrel connector. Cut a notch in one of the chassis edges (assuming a top/bottom box). The square section fits inside the box, the cone-shaped section is outside the box. Similar cord-sets exist for mains voltage applications.

 
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