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Author Topic: current capacity of breadboards  (Read 2790 times)
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I have a robot that will be at peak using 7 amps at 12 volts when all systems are on. In the past I usually used breadboard power rails and that worked just fine for smaller robots. I have many devices using 1 amp at 12 volts (water pump, halogen lights, motors, wireless router ) and none of them really exceeding 1 amp each.  how can I manage this kind of current and all of these connections?
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In that case I'd use suitably rated wires to link the high current components and only use PCB/plugboard/breadboard for the low current parts. The currents and voltages you're dealing with are well within the normal range of automotive wiring.
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Here maybe you can get a idea here I've use relays on strip board like this
the Red is 120 volts @ 10 amps the Gray is the going to the load

The blue are control lines

I used this to fix a relay that I couldn't find a match for worked fine. I also paint over the copper after I'm done with lacquer black nail polish works great as  insulation.


* StripBoard.PNG (127.46 KB, 525x277 - viewed 139 times.)
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Look closely at the way a breadboard is constructed. Do you really think that the breadboard is designed to carry 1200 watts? I hope your insurance is paid up (or even better, that you don't have any!).
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Here maybe you can get a idea here I've use relays on strip board like this
the Red is 120 volts @ 10 amps the Gray is the going to the load

The blue are control lines

I used this to fix a relay that I couldn't find a match for worked fine. I also paint over the copper after I'm done with lacquer black nail polish works great as  insulation.


What is the current rating of that track? If you don't know, then what is the cross-section area? Remember to exclude the holes from your calculation. For example, a cable rated at 5A continuous load would typically have a conductor diameter of about 1mm and a cross-section area of about 0.75mm square.
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If you ever peel back the backing material from a solderless breadboad you will see the material and it's size that connects the connection pins together, fairly 'beefy'. I don't know if such boards carry a max current spec, but I would think the limiting factor would be the resistance of the external wire to socket pin connections rather then the interconnecting paths. I would think 3 amp or less would be an effective safe max rating. I don't think 120v would be a limiting factor as the insulation is well made, but human error when sticking wires into and out of the pin holes could be very dramatic using household power! It would limit voltage and current to + or - 15 volts and 3 amps or less for solderless breadboards, but that's just a gut specification on my part.

Lefty
 
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I'm not showing one track it's two off them and the whole track is solder covered

And can safely handle the 10 amps

which gives a Trace Current Carrying  of about 12.5 amps
 
The track is 4 times as wide as the one on the stove PCB  and 1 once copper
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solderless breadboad are good for 2 amp that's if you have a good one cheap one maybe a 1/2 amp

And here some design charts to use http://www.armisteadtechnologies.com/trace.shtml
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what exactly happens if the max current on a breadboard is exceeded?
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I don't think you connected the grounds, Dave.
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Pretty green sparks
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Solderless bread boards are not a good idea for power over a 1/2 amp there to much that can go wrong with them. I would make a PCB or for one off things use a solder bread board with gang tracks and over size them.

Where I work I've fixed a lot of poorly made boards that controlled motors
The older boards always had solder covered tracks which helps to fix some poorly made boards.   
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The main problem is the resistance of the tracks which is much higher than actual copper wire, that will create heat as the current raises, heat will cause it to melt and perhaps short circuit producing some very nice sparks as the tracks probably blow apart(if ur power supply can handle it) all in a little cloud of black smoke, best way is to use some 18-22 gauge stranded wire soldered point to point, with the main feed wire being a little larger
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