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can aluminum foil sheild wires?

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  • can aluminum foil sheild wires?

    does aluminum foil shield wires against interference. I would like to wrap aluminum foil around my wires to shield them from EMI and then wrap electrical tape around them to hold it in. Do you think that would do me any good or would it make it an antenna for it. I cant get shielded rca at the moment for a good price. Is this an okay quick fix until i can get my hands on some shielded cable?
    "You know what I mean? But at the end of the day, it is what it is." - The most articulate thing someone could say.

  • #2
    Yes tin foil would work, I have used it in the past for various jobs.
    Data911 M5 system
    RR and iGo8PC
    Pioneer head unit
    Pioneer DEQ-9200 digital processor
    Phoenix gold line drivers
    Ultimate and Visonik amplifiers
    SMT 3 way active front stage
    Digital Design sub woofers
    3 runs of 0 gauge wire


    • #3
      It would be interesting to do a comparison with a CRO so see the actual difference this makes. Anyone willing to give it a go?
      Never let the truth get in the way of a good story


      • #4
        Would it help if you connect a wire to the foil and ground it?


        • #5
          You can find really cheap rca's of various quality at

          Seems like alot of work to wrap all of your wires. If you do it, make sure you ground the foil at one or both ends. Theres not much point in wrapping them if you don't ground it.


          • #6
            Think about what you are shielding your wiring from: EMI (Electro Magnetic Interference)....."electrical noise" . This "noise" is a result of magnetic fields....fields that occur whenever electricity flows through a wire. (Electricity 101 class). These fields are created around one wire (with a current flowing through it) and then cross another wire where they generate a new current. (Move a magnet across a wire and you will generate voltage in that wire).


            To shield a wire you can use a "drain". The best shielding would be soft iron. It will conduct the magnetic flux lines 1000 times better than air, and much better than copper or aluminum. Of course this drain needs to be grounded.

            Another commonly used method in sensitive automotive (and other) circuits is to use "twisted pairs". In automotive aplications these can be found on very sensitive computer circuits such as ABS speed sensors or some engine sensors. More info on that can be found here:


            Its always a good idea to be aware of the types of signals traveling in the wiring. Straight DC does not normally cause an issue as its magnetic field is stationary. However, if you have pulsating DC or AC in wiring you are going to have more problems with EMI as you will have moving magnetic fields.

            Early on I mentioned using iron as a shield. Think about the structure of an automobile: its STEEL (which is iron). Many times you can place wiring in such a fashion that you take advantage of the structure of the vehicle itself to act as a shield. Plan your wiring so that wires that are sensitive to noise are not close to wires that produce noise. Also, if you cross other wires, do it at a right angle if possible as you reduce the area where EMI is a problem.

            Thoughtful placement of wiring can go a long way in reducing electrical "noise".


            • #7
              Twisted pair does not do much unless you are using a "balanced system". Automotive communication lines are balanced lines, computer networks also used balanced signal transmission.
              System always under construction


              • #8
                What did you mean by grounding the aluminum foil?

                How would one go about doing that? Sorry, I'm just not getting the image in my head, haha, i'm not an electrically inclined person, yet. I'm thinking about tin-foiling the wires coming out of my M2-ATX, and also my RCA cables, and my VGA cable, in order to reduce the interference. Especially for my monitor, i get the horizontal lines when the engine is running.

                Could this be solved by a Big 3 Upgrade?


                • #9
                  I have successfully used aluminum foil tape for shielding on IDC type ribbon cables. I had to make some Mini centronics (MDR) cables from scratch, I didn't buy the $8K crimper from 3M so I could not used their shielded 100 conductor cable, I bought IDC MRD ends and made my own ghetto crimper. Anyhow, one of the cables I made was for LVDS video and Serial data on the same cable. When I hooked it up the video was almost unusable. I wrapped the cable in the self adhesive aluminum tape, being sure to make good contact with the MDR ends and it worked perfectly.

                  The Foil tape is about 3 inches wide and is commonly used for HVAC duct work. It is heavier gauge than kitchen foil, and very, very sticky. I imagine you can buy it at the big box home improvement stores, but I got mine from a actual HVAC supply house.



                  • #10
                    Originally posted by azngujuonfire View Post
                    What did you mean by grounding the aluminum foil?
                    Attach the aluminum foil to the bare metal frame of the car.

                    Especially for my monitor, i get the horizontal lines when the engine is running.

                    Could this be solved by a Big 3 Upgrade?
                    What monitor do you have? The Lilliputs have an external nosie filter for the power wires for the monitor. It might also help to keep your VGA extension cable away from high current power wires. BIG 3 upgrade will not filter the lines out.
                    System always under construction


                    • #11
                      I have a Lilliput 669 HB. It has an external noise filter? Right now I'm using the cigarette lighter adapter to power the monitor. My VGA cable is like right next to and runs along the 12V wire to the M2-ATX, as well as the ignition wire that and ground wire that goes inoto the m2-atx, could that be the problem? Would wrapping these wires in tin foil help? And about attaching the tin foil to the bare metal of the car, would it have to be like a piece of aluminum foil that is attached to the wire that it is covering?


                      • #12
                        To ground it, you add a wire with no insulation to the bundle of wires you are shielding.

                        Wrap this uninsulated wire around the outside of the others so it can create a good connection with the shielding.

                        Soldering, or at least taping it to the inside of the shielding would be best (if you use foil. For the aluminum tape you attach this wire to the outside)

                        If you are separately wrapping multiple wires you can run the separate ground wires to each other and bond them all to a thicker wire which would be connected to the chassis. For a single "wrap" you would just connect the one ground to the chassis.

                        The grounding gives the EMI somewhere to go. Without it, you are simply creating a nearly useless physical obstruction for EMI.