Replies

1. 
   DanH | Sep 28, 2009 02:04am | #1

   The only interference that might occur would be due to the thermostat. An electronic thermostat might function like a dimmer and produce "hash", but no more so than a regular dimmer. A mechanical thermostat would produce switching transients as it goes on and off, but again no worse than switching on and off lightbulbs.

   And foil covering on the wires wouldn't do much to prevent interference anyway.

   I smell snake oil (or simply an installer who doesn't know why the manufacturer might have covered the cable with foil).

   As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
2. 
   sandalboy | Sep 28, 2009 03:42am | #2

   Foil shielding can reduce rf interference quite well. Think coax TV wire or xlr type audio cables. I think that the important thing is that the shielding is grounded. I don't know if in floor heat would present too much of a problem though. I know that our electric heating pads and such cause no interference in my home.

1. 
   edwardh1 | Sep 28, 2009 04:30am | #3

   metal screen also works, but whats the source of the rf?
   Ask the manufacturer of the material- perhaps by e mail or letter.

2. 
   DanH | Sep 28, 2009 05:00am | #4

   I'll repeat: Foil shielding on the heating cable will do essentially no good to stop interference, even if there really was some coming from the cable. Metal screen over the cable (and under, perhaps) would be more effective (if you actually needed something).
   As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz

1. 
   sandalboy | Sep 28, 2009 06:05am | #5

   I'm not sure where you think that I said in floor heat would cause an RF problem. All I mentioned is that shielded cable does work in many cases, but it needs to be grounded to be effective. As far as audio cabling I can tell you from experience, that foil or whatever metalic shielding that the manufacturer chooses does work. We use XLR balanced cabling in our PA system, and it is readily apparent when the shielding is damaged or not grounded. Electric in floor heat will emit measurable RF like any other electrical conductor, just not likely enough to be an issue with a home network.

1. 
   DanH | Sep 28, 2009 06:37am | #6

   It works for audio cables, where BOTH wires are inside the shield.
   As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz

1. 
   sandalboy | Sep 28, 2009 08:50am | #7

   Correct, and I never suggested that audio cables using the shield as a conductor do anything to keep RF out. But the shielding also works with single conductors inside as used in antenna wires. There is a good reason that sensitive low level wiring has shielding, whether to keep RF out or in.In my opinion, if the wire cost is not much different, I would opt for properly installed shielded radiant wire (if available) vs. non-shielded.This is silly to argue about though since there would unlikely be any problems with a home network either way.

2. 
   DanH | Sep 28, 2009 03:47pm | #8

   Antenna wires function as a wave guide. Different principle.
   As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz

2. 
   junkhound | Sep 28, 2009 05:05pm | #9

   Electric in floor heat will emit measurable RF like any other electrical conductor

    

   HUH??  RF???  Only if you are driving your in floor electric heat with a PWM system, which I dont think are even commercially available. 

   OTOH, any conductor will re-emit RF - IF one part of it is in an RF field... 

   Put it another way.  Put an electric heater powered with a 60 Hz sine wave in a Mil-std-462 compliant screen room,  you will measure ZERO RF emissions. 

   paying more for shielding 60 Hz heaters is a rip-off for any home - there are, however,  some specific military or medical installations where it can be an advantage due to the re-emission factors.

3. 
   Billy | Oct 02, 2009 06:55am | #10

   I think they're screwed up -- there is a supposed issue related to EMF radiation (not RFI), but I'm not sure it's a real isse.

   This is what Suntouch radiant says about it:

   http://www.suntouch.com/emf/

   Billy

1. 
   DanH | Oct 02, 2009 06:59am | #11

   What that site says is more or less true. There's no strong evidence that "EMF" fields at 60Hz can cause problems, but if one's worried about it, heat cables that have both wires in them will produce virtually zero EMF, while those with a single wire in a loop will produce lots (and no amount of "shielding" will trap the EMF).
   As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz

1. 
   TomW | Oct 02, 2009 07:07am | #12

   Nope, gotta trap it with one of these.

   View Image

1. 
   DanH | Oct 02, 2009 07:23am | #14

   Gotta line it with tinfoil first.
   As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz

2. 
   Billy | Oct 02, 2009 07:13am | #13

   Yep, it looks like theu're set up as a twisted pair inside the jacket.

   Billy