Wiring question: Going from larger wire to smaller wire

In summary, when going from a larger wire to a smaller wire, there are a few things to keep in mind. First, it is important to make sure that the smaller wire can handle the same amount of current as the larger wire. This can be determined by checking the wire gauge and consulting a wire size chart. Additionally, proper connections must be made between the two wires to ensure a secure and safe electrical connection. Finally, the smaller wire may experience more resistance and heat buildup, so it is important to monitor and potentially adjust for this difference.
  • #1
atlbraves49
81
0
I could use some tips on the following setup..


Will have a larger wire (i think its 14 AWG) going into a metal box, but then inside the box i need to switch over to smaller wires (breadboard type) for the circuitry inside. Is that possible? And if so, how do i go about making that switch over.


Just a basic idea of what I am talking about.. the red wire is the larger wire, and the blue wire is what's connect to a breadboard inside the box

http://img3.imageshack.us/img3/737/wiringgr8.jpg
 
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  • #2
atlbraves49 said:
I could use some tips on the following setup..


Will have a larger wire (i think its 14 AWG) going into a metal box, but then inside the box i need to switch over to smaller wires (breadboard type) for the circuitry inside. Is that possible? And if so, how do i go about making that switch over.


Just a basic idea of what I am talking about.. the red wire is the larger wire, and the blue wire is what's connect to a breadboard inside the box

Either solder the wires together or use a wire nut.
 
  • #3
Or used a connector block of some sort. They have ones specifically for converting wiresizes. Search on Digikey.com.
 
  • #4
I guess another question is.. can breadboard type wires handle 25W? Id like to put my power mosfet and resistor on a breadboard and connect them that way.. i just want to make sure the wires can handle it too.
 
  • #5
atlbraves49 said:
I guess another question is.. can breadboard type wires handle 25W? Id like to put my power mosfet and resistor on a breadboard and connect them that way.. i just want to make sure the wires can handle it too.

If you mean the little white spring-contact 0.1" grid breadboards, no. They should have a spec for the max current per contact -- I'd guess it's around 100mA, but it could be less. The little white plugboards are for low-power digital and analog prototyping.

You will be needing heat sinks to the metal case for your power prototype, right? You can prototype low-power control circuitry on the breadboard, and using flying wires up to the power stuff mounted on heatsinks.

BTW, depending on your power device, its tab (or whatever) may not be ground. You may need a piece of mica between the power device and the heat sink -- check the specs of the device. And it helps to use heatsink grease -- gives a lower Theta J-A.
 
  • #6
im talking about something like this:
http://www.allelectronics.com/make-a-store/item/PB-400/SOLDERLESS-BREADBOARD-400-CONTACTS/-/1.html

was planning on inserting the power mosfet:
http://www.irf.com/product-info/datasheets/data/irf640npbf.pdf

in series with this resistor:
http://www.ohmite.com/catalog/pdf/tch.pdf

with typical breadboard wires

and both the power mosfet and resistor will be fitted with their own heatsinks
http://www.aavidthermalloy.com/cgi-bin/stdisp.pl?Pnum=6396bg
http://www.futureelectronics.com/en...-accessories/Pages/4002283-593002B03400G.aspx
 
  • #7
atlbraves49 said:
im talking about something like this:
http://www.allelectronics.com/make-a-store/item/PB-400/SOLDERLESS-BREADBOARD-400-CONTACTS/-/1.html

I don't see a contact rating, but I'd still guess about 100mA max. What currents are you wanting to run through the breadboard?
 
  • #9
berkeman said:
I don't see a contact rating, but I'd still guess about 100mA max. What currents are you wanting to run through the breadboard?


not sure exactly but probably
anywhere between 0.5A and maybe 5A?

if not a breadboard, what kind of board should i use to make these connections?
 
  • #10
atlbraves49 said:
not sure exactly but probably
anywhere between 0.5A and maybe 5A?

if not a breadboard, what kind of board should i use to make these connections?

The next step up from the white plugboards is to use 0.1" spaced prototype boards, which have a plated-though hole per pad on that spacing. They come in lots of different form factors and styles:

http://images.google.com/images?hl=en&q=prototype+board+plated&gbv=2

Even that is going to be problematic for 5A current levels. You can probably use the protoboard up to about 500mA to 1A, and then beyond that you will either need to just use soldered fly-wires, or make your own PC board with wide traces:

http://www.desmith.net/NMdS/Electronics/TraceWidth.html
 
  • #11
how many components you looking at here? if it's just a few, i wouldn't even bother with things like plated-through hole perfboard. just grab a piece of plain perfboard with no metal, just holes. cut to size and put on standoffs in the box. then just poke all your components through the holes and solder up appropriate size wires. easy-peasy. it won't be pretty, but it's hidden in the box.
 
  • #12
Since this thread is trending towards simpler and simpler...

Assuming you solder a few components together, and don't have any perfboard you can use hot glue to insulate and add extra robustness to your circuit. TIP: use a heat gun or a blow driver to reflow the glue and make it look less like you hot glued your circuitry together. Great for waterproofing / encapsulating small circuits.

Think of it as a poor man's potting compound / epoxy. I suppose you could use electrical tape, but I'm not so much a fan of that, since it tends to get pretty messy and falls apart depending on conditions and how much you paid for the roll. Hot glue also usually comes off pretty clean if you rub at it, and make a cut or few.

It could be worse. I remember reading about a pita breadboard a while ago, and an associate of mine used cardboard for a temporary job.
 

Related to Wiring question: Going from larger wire to smaller wire

1. What is the purpose of going from a larger wire to a smaller wire?

The purpose of going from a larger wire to a smaller wire is to reduce the amount of current flowing through the circuit. This can help prevent overheating and potential safety hazards.

2. How do I determine the appropriate gauge size for my wiring?

The appropriate gauge size for wiring is determined by the amount of current the circuit will be carrying. The higher the current, the larger the wire gauge needed to safely handle it. You can consult a wire gauge chart or consult a professional electrician for help with determining the appropriate size.

3. Can I use a wire with a smaller gauge than what is recommended?

No, it is not recommended to use a wire with a smaller gauge than what is recommended for the circuit. This can lead to overheating and potential safety hazards. It is important to always use the appropriate wire size for the circuit.

4. Is there a limit to how many times I can go from a larger wire to a smaller wire in a circuit?

Yes, there is a limit to how many times you can go from a larger wire to a smaller wire in a circuit. Each connection point adds resistance to the circuit, which can affect its overall efficiency and safety. It is best to limit the number of connections in a circuit and use the appropriate wire size throughout.

5. Are there any other factors I should consider when going from a larger wire to a smaller wire?

Yes, there are other factors to consider when going from a larger wire to a smaller wire. It is important to also consider the length of the wire and the voltage of the circuit. Longer wires and higher voltages require larger wire gauges to ensure safe and efficient operation. It is best to consult a professional electrician for help with determining the appropriate wire size for your specific circuit.

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