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what type of electrical wire holds up best to repetitive bending

rimcanyon

Diamond
Joined
Sep 28, 2002
Location
Salinas, CA USA
I am looking for some 18 ga. wire for an application where the wire will see a lot of flex. Two wires will run from an entry door into the jamb, and there will be 1/16-3/32" clearance when the door is closed.
 
I would look at the security supply companies.

I see an "electric strike" mounted on some doors, and there is a small
metal armored cable sending current to the door.

No need to re-engineer the job, it's already been figured out for you
(and probably meets all codes too)
4612 Power Transfer Device
 
In general the finest stranding will have the best life. The mechanism is that bending the wire below the yield point will have the least fatigue. The thicker the wire, the less deflection will reach that point. If you can do it, aligne the wire with the hinge line so that the cable is only twisted rather than bent. Look at the door cable on a car with power leads to the electric windows and electric locks. These cables must stand hundreds of thousands of flexes.

Bill
 
Tell us more about the application. Voltage requirements, length between points of attachment, current requirements, degree of flexing. How far must the door be allowed to swing, 90*, 170*? When the door is opened, the distance between the points of attachment will increase, so when the door is closed, the wire will need to have a place to go.

Tom
 
I am looking for some 18 ga. wire for an application where the wire will see a lot of flex. Two wires will run from an entry door into the jamb, and there will be 1/16-3/32" clearance when the door is closed.

No room for a festoon then.
Current/voltage/bandwidth?
Access to the sills/stiles?
Why not a contact? Can the connection be made only open or closed?
 
How many?

USB mouse cords of industrial grade units are good.

Lots of instrument cords that have rubber jacket combined with cotton cording or better braiding.

Telephone patch cords can be made this way.

Try contacting vendor like digikey and ask a human to help as many options.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
As mentioned by Bill above, the finer the strands the batter. And if the wire must bend, the bigger radius the better. Not only the strands need to fine but the insulation flexible. I found the silicon insulated wire used for RC cars models is one of the best deals for high flexibility wire. Available in 10-18 gauges

BNTECHGO 12 Gauge Silicone Wire Ultra Flexible 1 Feet high temp 2 deg C 6V 12 AWG Silicone Wire 68 Strands of Tinned Copper Wire Stranded Wire Model Battery Cable Black and Red Each Color 5 ft: Amazon.com: Industrial & Scientific
 
What Bill (9100) said.

The best is to set it up so the wire is twisted, and not bent. This works for single wires, and it works for reasonable sized bundles of wire as well. "Reasonable" means the bundle diameter is at least 15 or 20 times less than the length of the twisted section. The door etc needs to move freely, and not have the wires acting like a screen door spring.

My experience is that bends will break long before twisted wires will. The key is, however, to not let the wire end up bending at the end of the twisted section, because it may break there.

I am not clear about the geometry of the situation the OP has. It seems from my mental picture as if that may be much smaller than is desirable for a bending situation.
 
As mentioned by Bill above, the finer the strands the batter. And if the wire must bend, the bigger radius the better. Not only the strands need to fine but the insulation flexible. I found the silicon insulated wire used for RC cars models is one of the best deals for high flexibility wire. Available in 10-18 gauges

BNTECHGO 12 Gauge Silicone Wire Ultra Flexible 1 Feet high temp 2 deg C 6V 12 AWG Silicone Wire 68 Strands of Tinned Copper Wire Stranded Wire Model Battery Cable Black and Red Each Color 5 ft: Amazon.com: Industrial & Scientific

If you can afford it, Cooner Wire makes super flexible wire and cables.

16 gauges wire with 665 strands!

Hookup Wire NEF
 

Good link. A customer had a Chevalier 20 X 36 grinder stop with a broken wire in the cable to the table. It was a critical situation because it halted production of their main product. I found a cable locally that worked but was far from ideal and will probably fail again. This discussion prompted me to look for a replacement, either from Chevalier or someone like Cooner and store it.

Bill
 
When the application allows I use Cicoil's high-flex line. Available from Mcmaster-Carr. Can be a bit of a pain to terminate into connectors without a backshell but excellent in continuous motion and harsh environments. If IP67 or higher is required I suggest a nice backshell design with some even nicer adhesion promoters due to the silicon. Cicoil Flat Cable - Home
 
Data point: bog standard 18 ga. stranded "hook-up" wire is used in my fridge, 'twisting' thru the center of hinge, carrying 120V about 2A power to switch ice and water dispenser solenoids. Lifespan was 12 years with average daily fridge use in a household of 3.
 
What you want is "test lead" wire. It is both fine stranded and also has insulation that is extra flexible.

I have already narrowed this search to 18 gauge:

Single Conductor Cables (Hook-Up Wire) | Cables, Wires | DigiKey

I have never seen a test lead that broke anywhere other then the point of attachment and that can be easily remedied with proper strain relief that avoids flexing at that point. A simple clamp will do. You can work with it just like any hook-up wire: solder, crimp, screw terminal, etc. It should present no termination problems.
 
I am looking for some 18 ga. wire for an application where the wire will see a lot of flex. Two wires will run from an entry door into the jamb, and there will be 1/16-3/32" clearance when the door is closed.

Though this may be outside of the realm of how much fabrication you want to do in this project, this is just a friendly reminder that there 'is' a product made especially for such continuous flex applications: Flat ribbon cable. It's the same thing that (used to be) used is applications like laptop computers (where the screen is constantly opened and closed - just like a door). In your case with close tolerance (not a lot of space for the wire/cable), the thin ribbon cable is often a good choice. The only drawback is that it often requires a little more fabrication to devise the connection/connectors. Good luck.
Custom-Rainbow-Ribbon-Cable-Utilized-by-NASA-for-Real-Time-Data-Acquisition.jpg
 

Whats nice is they sell it all by the meter too and have more flavors than than you could wish for from coax to vast multi cores and power - fibre optics. Works out cheap too because again they sell by the meter, just a happy customer who uses it for a multitude of multi core - power transmission both on moving things and in cable chains.
 
Yep IGUS. I used to buy 230 ft long servo cable with 3 power conductors, ground and two braided shielded twisted pairs for encoders. Held up very well reeling and unreeling all day long.
 








 
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