Transmission of 3.3v

Can a 3.3v be transmitted through a 30 awg single core wire upto 30m.

Yes, the question is what the side effects are. For instance, long wires

  • can act as antenna, when you want to transfer a signal at 3.3V you will get noise that you will need to filter
  • can act as coils, when you switch of the voltage the magnetic field around the wire will collapse and the current wants to continue to flow but it cannot because you opened a switch that will increase the voltage and potentially damage your circuit
  • have resistance, with larger currents the voltage will drop across the wire

In this question, you will certainly experience some voltage drop.

The solution should be based upon a current loop principle, which basically means provide a slightly stronger pull-up at a voltage that works over the distance- then divide that switched value into your input to get a clean HIGH/LOW voltage swing.

A #30 wire has a resistance of 0.1 ohms/ foot or 0.1 * 3.28 = 0.328 Ohms/Meter

60 meters (path out and return) * 0.328 = ~ 20 ohms

Now the question is will 20 ohms be a problem for your circuit? You can add capacitance at the end to store energy for any short term event.

Just a note, Resistance drops in 1/2 for each 3 wire sizes larger.

I don't know your situation but I think you would be better off with a larger wire. Also you will find #30 wire wrap wire is not very durable and because it is a solid wire, easy to break. As your link states this wire is 0.25mm diameter.

1 Like

Hi, @adithyasm65

Can you tell us the application?
Do you want to use it to power a device up to 30m away?
If so how much current?
If not is it as a signal system transmitting data?

Thanks.. Tom... :smiley: :+1: :coffee: :australia:

Actually i was planning to automate a water pumping mechanism, so I need to connect the relay with the esp8266 which is at a distance of 30m away.


So the 3V3 is to supply power to the relay coil?

What is your project power supplies?
Can you post a diagram of your project?

Thanks.. Tom.. :smiley: :+1: :coffee: :australia:

Come on now! Just why are you referring to this particular wire which is intended for a completely different purpose!

Looking for the cheapest option is not necessarily a sensible idea, certainly not if you lack the important design skills. It should be obvious that you need two wires for a start, and related to Klaus' comments, you should be using a twin or "figure eight" cable. You could twist two runs of the wire you cite, together to achieve that but it may not be as sturdy as you might wish.

You really need to explain how you propose to physically run this cable.

You also need to explain what relay it is you want to control and what the "water pumping mechanism" is, how it is powered and how you propose to connect the ESP8266. A 3.3 V relay is going to be inconvenient and an ESP8266 cannot operate a relay directly, so you basically should not be transmitting a 3.3 V signal along your wire.

If you provide some sensible information here, we can certainly advise how to arrange it, but so far, you are getting nowhere, fast. :astonished:

From here;

How big a Lipo are you aiming to use?

Tom... :smiley: :+1: :coffee: :australia:

Beware of using this wire. It is NOT wire wrapping wire as it has NO coating of tin or other metal to protect the copper. The bare copper will begin to corrode as soon as the pvc coating is removed.

You could use more than one length if this is all you have.
For example, if you were wiring out a battery you could have 3 lengths on the positive and 3 lengths on the negative.
It's not the ideal but -- sometimes a guy has to work with what he has.

First question is
Which costs less
Spool of wire
Second ESP8266?

Assume you have all the power needed at the pump/relay end.

Lots of ESP8266 runn8ng on solar for the remote.

This means you have power on site, why not use that to power the board and relay?

Well, I basically brought that up in #8. Let's see if the OP ever provides any information. :roll_eyes:

Okay lemme explain the entire scenario, as I mentioned earlier I need to automate a water pumping mechanism using esp8266.the board along with ultrasonic sensor is kept on top of the overhead tank.The board is powered using a 3.7v cell.Coming to the relay part...I need to connect 3 wires .. gnd,vcc and trigger from esp8266 to the relay which is near the pump 30m away from esp8266.vcc,gnd are connected to corresponding pins of the relay module.The trigger is fed to the base of 2N222 and gnd to the emitter.The input pin of the relay is connected to the collector terminal.

This is my setup, except for that 30m cable for connection... everything works perfectly for my cause.Only concerned about the cable and its cost.sorry for the inadequate informations provided earlier.

Will the wire be exposed to the elements? Sunlight/ UV will destroy the insulation of your wires, unless it is rates for such exposure.

Yes probably

Ignoring the physical capability of such wire, can you add 25 ohms into your setup to simulate the resistance of the wire? It would be a good test to answer part of your question.

Ohh that's great!

Well, you have still not answered the necessary detail. :roll_eyes:

And you have quite a number of problems. One is for example, the suggestion that you are going to power the ESP8266 with IIRC, an 18650 LiPo battery - but how are you going to charge the battery every couple of days?

Using a 3.3 V relay is going to be rather inefficient for a start. If we presume you mean a common SRD-03VDC-SL-C relay, its coil resistance is in fact 25 Ohms and requires 120 mA when operating. That means it will not work at all with a 25 Ohm series resistance in your wires and even without the wires, 125 mA will be a significant discharge on the battery.

Next problem is that that the Songle relay is not particularly durable. What sort of pump is it supposed to be controlling? You probably need it to control a proper mains contactor in order to switch the pump.

But there is the absurdity. What is powering your pump? If it is mains electricity you have no reason to use a battery and its associated problems. Whatever the power source is for the pump, you use that power source to supply your ESP system and the (higher voltage version of the) relay. 25 Ohms in series with the 5 V supply back to the regulator on an ESP8266 module is not so much of a problem.

And why are you using the ESP8266 in the first place? Presumably for WiFi connectivity, otherwise you would be using a Pro Mini. So if you are using WiFi, there is no need to run a wire 30 meters in a conduit (a piece of hose would probably suffice) to protect it from the sun. You use a second ESP8266 at the pump.

You really seem to be doing it all wrong! :grin: