<p>You could absolutely do that.</p>

<p>Ultimately, the amount of current you can push through a wire/breadboard/connector depends on its resistance: for a given current <strong>I</strong>, a component with a resistance of <strong>R</strong> will have a voltage drop of <strong>V = I x R</strong> across it, resulting in a power dissipation of <strong>I^2 x R</strong> watts.</p>

<p>I measured the resistance of breadboard traces to be around 7 Ohm/meter (measurement subject to some error, but this is the value I got testing over a 300mm stretch at 0.2A). This is quite high, the wires that came with your stepper motor are probably in the range of 0.1 Ohm/meter. If you had a stepper running at 2A, you'd waste 28W of power in a meter of breadboard rails.</p>

<p>Thankfully you're only going to be dealing with a very short stretch of breadboard (wasting "only" 0.8W for 4 wires over a 3 pin stretch each). It would probably be OK, but it's not ideal. Make sure the connection is good (and keep an eye on it initially) as a bad connection can result in significantly higher resistance and that might generate enough to melt your breadboard and short things out.</p>

<p>A better way of doing this would be to simply solder the wires together, or (if you don't want to permanently connect the steppers) use the pin headers you mentioned, and solder them together directly (for example on a piece of perfboard or perhaps just link them up directly with a few pieces of thick wire).</p>

CC BY-SA 3.0
2016-05-02T19:02:53.787Z
So you measure resistance to make sure it's not going to catch on fire right?
leeand00
CC BY-SA 3.0
2016-05-02T19:03:18.243Z
Is there a more ideal way of doing this?
leeand00
CC BY-SA 3.0
2016-05-02T19:35:52.573Z
I added a paragraph on a better way of doing this.
Tom van der Zanden
CC BY-SA 3.0
2016-05-03T15:43:53.983Z
This misses the key concern - it is not the resistance of the length of the contacts in the breadboard that is a potential issue, but rather the small contact area between the breadboard leafs and the header pins.
Chris Stratton
CC BY-SA 3.0
2016-05-04T02:30:56.603Z
Nevermind, My board actually has both Z-axis inputs on it.
leeand00
CC BY-SA 3.0
2016-05-04T20:15:17.693Z
@ChrisStratton The resistance due to the connection is on the order of 0.1Ohm. Not too great to be of much concern (but neither is the resistance of a short section of the tracks).
Tom van der Zanden
CC BY-SA 3.0
2016-05-04T21:00:21.053Z
No, you are quite mistaken about that - the resistance is not necessarily that small, especially when subjected to higher than designed current!  **It is grossly ignorant to model contacts as if they were wires!**
Chris Stratton
CC BY-SA 3.0
2016-05-04T21:26:25.037Z
[This particular breadboard](http://www.mouser.com/ds/2/58/BPS-MAR-BB300+BB400-001-8664.pdf) is rated for 2A, so the kinds of currents needed for steppers are definitely within the realm of possibilities for breadboards. I just passed 600mA through a breadboard and only got a voltage drop of 30mV (measuring between two rows of a breadboard joined by a single jumper wire).
Tom van der Zanden
CC BY-SA 3.0
2016-05-04T21:32:25.333Z
Your mistaking is in not modeling contact degradation - sure, it might act nice when new, but breadboard contacts are very poor in contact area and oxide piercing compared to true mating connectors.  Not to mention assuming all breadboards are quality... most are not.
Chris Stratton
CC BY-SA 3.0
2016-05-02T18:39:56.457Z
2016-05-02T19:35:30.667Z
2016-05-02T19:35:30.667Z
Tom van der Zanden
<p>Can I use a <a href="https://www.newbiehack.com/categories/3d-printer-component-connector-male-2!54-pitch-newbiehack-connectors-male-2!54-pitch#prettyPhoto" rel="nofollow">pin header</a> with the molex on my <a href="http://www.kysanelectronics.com/graphics/1124090-8.3.15.pdf" rel="nofollow">Nema 17 motors</a> and a bread board to wire up the z-axis motors in series?</p>

<p>Also, do breadboards and pin headers have ratings, the way that wires do?</p>

<printer-building><prusa-i3-rework><wiring><nema-17>
Can I use a pin header in a breadboard to wire up the z-axis motors in parallel?
leeand00
# Can I use a pin header in a breadboard to wire up the z-axis motors in parallel?

(Asked by: username_0 on 2016-05-02)

Can I use a [pin header](https://www.newbiehack.com/categories/3d-printer-component-connector-male-2!54-pitch-newbiehack-connectors-male-2!54-pitch#prettyPhoto) with the molex on my [Nema 17 motors](http://www.kysanelectronics.com/graphics/1124090-8.3.15.pdf) and a bread board to wire up the z-axis motors in series?

Also, do breadboards and pin headers have ratings, the way that wires do?

**Tags:** printer-building, prusa-i3-rework, wiring, nema-17


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## 1 answers

### Answer by username_1 on 2016-05-02. Score: 1

You could absolutely do that.

Ultimately, the amount of current you can push through a wire/breadboard/connector depends on its resistance: for a given current **I**, a component with a resistance of **R** will have a voltage drop of **V = I x R** across it, resulting in a power dissipation of **I^2 x R** watts.

I measured the resistance of breadboard traces to be around 7 Ohm/meter (measurement subject to some error, but this is the value I got testing over a 300mm stretch at 0.2A). This is quite high, the wires that came with your stepper motor are probably in the range of 0.1 Ohm/meter. If you had a stepper running at 2A, you'd waste 28W of power in a meter of breadboard rails.

Thankfully you're only going to be dealing with a very short stretch of breadboard (wasting "only" 0.8W for 4 wires over a 3 pin stretch each). It would probably be OK, but it's not ideal. Make sure the connection is good (and keep an eye on it initially) as a bad connection can result in significantly higher resistance and that might generate enough to melt your breadboard and short things out.

A better way of doing this would be to simply solder the wires together, or (if you don't want to permanently connect the steppers) use the pin headers you mentioned, and solder them together directly (for example on a piece of perfboard or perhaps just link them up directly with a few pieces of thick wire).

> **Comments:**
> **username_0**: So you measure resistance to make sure it's not going to catch on fire right?  
> **username_0**: Is there a more ideal way of doing this?  
> **username_1**: I added a paragraph on a better way of doing this.  
> **username_2**: This misses the key concern - it is not the resistance of the length of the contacts in the breadboard that is a potential issue, but rather the small contact area between the breadboard leafs and the header pins.  
> **username_0**: Nevermind, My board actually has both Z-axis inputs on it.  
> **username_1**: @username_2 The resistance due to the connection is on the order of 0.1Ohm. Not too great to be of much concern (but neither is the resistance of a short section of the tracks).  
> **username_2**: No, you are quite mistaken about that - the resistance is not necessarily that small, especially when subjected to higher than designed current!  **It is grossly ignorant to model contacts as if they were wires!**  
> **username_1**: [This particular breadboard](http://www.mouser.com/ds/2/58/BPS-MAR-BB300+BB400-001-8664.pdf) is rated for 2A, so the kinds of currents needed for steppers are definitely within the realm of possibilities for breadboards. I just passed 600mA through a breadboard and only got a voltage drop of 30mV (measuring between two rows of a breadboard joined by a single jumper wire).  
> **username_2**: Your mistaking is in not modeling contact degradation - sure, it might act nice when new, but breadboard contacts are very poor in contact area and oxide piercing compared to true mating connectors.  Not to mention assuming all breadboards are quality... most are not.  

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