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I am buying a home that is under construction. The developer installed the vertical Cat6 Ethernet and RG6 coaxial cable runs from the basement to the attic in the wall immediately behind where the stove/range will go. My concern is that I was hoping to get an induction range in the near future. Would the magnetic fields produced by an induction range extend far enough to induce interference in the Cat6 and RG6 cables in the wall behind the range?

  • What are those cables transmitting? What is the data rate you are using the Cat6 for? 10, 100, 1000 and 10,000 Mbps can all be carried by CAT6 with differing levels of noise immunity. Is the RG6 carrying an analog signal like the run between a dish and a receiver? Is the RG6 for a cable modem or digital cable set-top-box? – alx9r Apr 26 '17 at 14:36
  • The Cat6 will be used at 1000 Mbps until such time as I get a router that supports 10 Gbps. Even at that point though, I imagine most connected devices wouldn't exceed 1 Gbps with the exception of a desktop PC and media server, although the media server would probably be in the basement. There are two different uses for the RG6. One will connect a digital antenna in the attic to a receiver or amplifier in the basement, the rest will be connect the TV(s) upstairs to the basement. The coax cable from outside to the modem runs separately through the floor. – B Sharp Apr 26 '17 at 19:13
  • In that case would endeavor to put some distance between the induction rangetop and those cables. I'd be comfortable with 10'. I have some first-hand experience with induction devices interfering with the signals you are expecting to put through those cables. If I can find some time I'll try to write an answer. – alx9r Apr 26 '17 at 19:33
  • @alx9r Thanks, I would appreciate more information. I can't really move the location of the range and moving the cables would be quite difficult since they are already installed. – B Sharp Apr 26 '17 at 23:42
  • I've written an answer. There's a bit of speculation involved here, so I hope my answer is still helpful. – alx9r Apr 27 '17 at 15:25
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TL;DR

If your rangetop is well-built and you are using those cables only for TCP ethernet traffic, you probably won't notice any problems. On the other hand, if you rangetop's switching circuitry is noisy, and you have some signals that are very sensitive to interference in those cables, you may be better off with a different cooking technology.

Long Answer

Would the magnetic fields produced by an induction range extend far enough to induce interference in the Cat6 and RG6 cables in the wall behind the range?

I don't think you can get a definitive answer to this without trying it. Here are the significant factors as I see them.

How Clean is the Power Switching in the Rangetop?

Any time large amounts of current are switched on and off there is a potential for emissions. Induction rangetops switch large amounts of current on an off. How significant those emissions are depends on a lot of factors that basically boil down to how well the rangetop's power circuitry was designed and manufactured to minimize emissions. One rangetop might emit a lot, while another might not. Because of the amount of current being switched, the potential for emissions is there.

How Close is the Rangetop to the Signal Cables?

The coupling of the interference to your cables will fall off with somewhere between the square and cube of the distance between your cables and your rangetop. If you move a sensitive signal cable from 10' away to 1' away from the source, I would expect to see between 100x and 1000x the interference. Most devices and cables are several feet apart. Designers and manufacturers know this, so they don't generally design unrelated devices and cables to operate correctly in very close proximity. If you have interference problems, manufacturers' first recommendation will often be to increase the distance between unrelated devices and cables.

How Sensitive are the Signals to Interference?

For network traffic running over those cables, interference will probably manifest as packet loss. I have seen packet loss occur on cables in close proximity to equipment that switches electric motors. The packet loss occurred only during transients periods when the motors were turning on and off. It's hard to guess how likely this is to occur in your situation. I know it's possible for at least electric motors and their drives.

You probably wouldn't notice packet loss for network traffic that uses reliable protocols like TCP (eg. web browsing, file downloads, phone apps). On the other hand, I have seen video distribution equipment/protocols that are designed for LANs that are very sensitive to dropped packets. I have seen the impact of dropped packets be as subtle as short black lines in the video and as dramatic as causing the feed to freeze altogether.

A common way to get sync'ed video streams to several displays throughout a home are devices that transmit HDMI over UTP/STP (like your CAT6). I have found that those devices are terribly sensitive to interference. Some don't seem to packetize the data or use ethernet physical signaling at all. Rather they seem to use the twisted pairs to transmit signals of some other standard. In one of my installations, those signals were interrupted by the current in the drive cables of a small electric motor that ran nearby.

  • Thank you for the thorough answer @alx9r. Unfortunately, I don't really have the option to move anything. I may see if I can devise an experiment to test a similar model before buying. Do you know if a metal plate or metallic film on the wall behind the range could help? – B Sharp Apr 27 '17 at 20:17
  • @BSharp In my experience EM shielding of any kind only ever reshapes the propagation or shape of the emissions or fields and that the resulting shape and propagation are very difficult to predict. A metal plate or metallic film could just as easily make matters worse as better. Reducing the source of emission, increasing separation, and improving immunity are the only reliable strategies I've found. – alx9r Apr 30 '17 at 14:11
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No, for two reasons:

  1. Induction ranges operate at kHz frequencies. Modern data transmission is done at frequencies that are thousands to millions of times higher.
  2. Cat6 is twisted, and RG6 is shielded, to mitigate noise from electrical interference.
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    Regarding your point 1 - the physics of induction doesn't place any requirement on the 'receiving' side other than it be conductive. Only if your induction uses a core to concentrate the magnetic field do you require any sort of magnetically permeable material - and that only in the core. Induction cooking works just as well with aluminum (non-magnetic) cookware as it does on cast-iron (magnetic) or stainless steel (depends on the alloy). – brhans Apr 25 '17 at 21:45
  • @brhans: Induction ranges operate via magnetic induction. They will not induce heat in anything but ferro-magnetic metals. Induction cooking does not work at all in aluminum or copper cookware. (Some induction cookware is clad in copper, but the heat is only produced by a ferrous core.) – feetwet Apr 25 '17 at 21:51
  • Seems I was misinformed as Wikipedia agrees with you. I was under the impression that induction cooking relies on the same principal as an induction furnace which works perfectly well on non-ferrous materials (commony used to melt gold & silver for jewelry work). Similarly lower-power induction applications like wireless charging of your smartphone don't require a ferromagnetic material. – brhans Apr 25 '17 at 22:04
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    Induction cook tops rely on changing magnetic fields to transfer energy. Any conductor in a changing magnetic field could have a current induced in it. The presence of a ferrous metal might alter the magnet field but, no matter the material, any conductor is susceptible to current induction by a changing magnetic field. In other words, point 1 in the answer is incorrect. – alx9r Apr 26 '17 at 14:26
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    @feetwet It's possible to provide a correct and practical answer without making statements that purport to rewrite the laws of physics. FWIW I have first-hand experience with magnetic fields from induction devices interrupting communication over UTP cabling. – alx9r Apr 26 '17 at 16:03

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