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Shielded, twisted pair wire for Lochinvar cascade feature.

JohnNY
JohnNY Member Posts: 3,230
in Thermostats and Controls
Hello, all. Does anyone have a source for buying a small quantity of shielded, twisted pair wire that I can use to link two boilers?
Many thanks,
John Cataneo
Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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Comments

  • ratio
    ratio Member Posts: 3,624
    Around here, one can get a cut of wire at an electrical supply house without too much difficulty, most|all of them carry at least something shielded. Online comes to mind, if you've got time to wait.

    A 500' roll of 18/3 stranded shielded plenum-rated wire is only around $100. I know I'd hate to buy that much when I only need a few feet, but if it's a get'r'dun today kind of thing, that might be the fastest, if the electrical supply houses don't want to make a cut for you.

    JohnNY
  • mattmia2
    mattmia2 Member Posts: 9,631
    just buy a cat 6a cable. is the actual impedance important?
    ChrisJ
  • mattmia2
    mattmia2 Member Posts: 9,631
    Also, this place will cut a lot of different cables:
    https://www.wireandcableyourway.com/
    JohnNY
  • mattmia2
    mattmia2 Member Posts: 9,631
    Looking at the manual, it looks like virtually any shielded 1 pair control cable would work.
  • hot_rod
    hot_rod Member Posts: 22,120
    I bought this for some solar sensor wiring.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    JohnNY
  • Gary Jansen_4
    Gary Jansen_4 Member Posts: 77
    I would think that most hardware stores and electronic shops would sell it by the foot.
    That's how it is in Wisconsin.

    That being said, I can't count the number of boilers, including Lochinvar, that I have used standard 18-2 thermostat wire for communication, and it has worked just fine.
    Thanks Gary
  • HVACNUT
    HVACNUT Member Posts: 5,829
    Does Lochinvar recommend shielded cable or is there the chance of interference to other equipment?
  • Zman
    Zman Member Posts: 7,569
    Lochinvar recommends it. Controls companies use miles of shielded wire. I usually grab some drops from a buddy that does controls work.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • JohnNY
    JohnNY Member Posts: 3,230
    mattmia2 said:

    just buy a cat 6a cable. is the actual impedance important?

    No, it's not. Thank you.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
    Classes
  • Gary Jansen_4
    Gary Jansen_4 Member Posts: 77
    How much do you need?
    I have tons of the stuff?
  • mattmia2
    mattmia2 Member Posts: 9,631
    The shield usually isn't important until you get in an environment where it is then you end up with weird intermittent issues.

    It also might not be to protect its signaling from interference but to keep its emissions within part 15 limits.
    ratio
  • HVACNUT
    HVACNUT Member Posts: 5,829
    Part 15, part 16. Whatever it takes.
    JohnNY
  • JohnNY
    JohnNY Member Posts: 3,230
    Gary Jansen_4 said:

    How much do you need?

    I have tons of the stuff?

    I need about 7 feet of the stuff but maybe I should just buy a roll.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
    Classes
  • Gary Jansen_4
    Gary Jansen_4 Member Posts: 77
    I'll send some out today.
    Thanks Gary
  • Gary Jansen_4
    Gary Jansen_4 Member Posts: 77
    If you are cascading 2 lochinvar boilers, then I am assuming you are running a header sensor. And possibly an outdoor sensor.
    Do you need the shielded wire for those 2 sensors also?
    Thanks Gary
  • JohnNY
    JohnNY Member Posts: 3,230
    Gary Jansen_4 said:

    I'll send some out today.

    Thanks Gary

    Gary, thank you so much. That's fantastic and very generous of you. The two sensors don't require shielded cable. Again, I'm very grateful.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
    Classes
  • Wellness
    Wellness Member Posts: 139
    edited June 2020
    Not sure what Lochinvar's requirements are, but shielded twisted pair cable is often incorrectly provisioned in computer network environments without grounding, thereby defeating the whole purpose of having the shield. It's not simply a matter of terminating the wire leads.
    mattmia2
  • mattmia2
    mattmia2 Member Posts: 9,631
    Wellness said:

    Not sure what Lochinvar's requirements are, but shielded twisted pair cable is often incorrectly provisioned in computer network environments without grounding, thereby defeating the whole purpose of having the shield. It's not simply a matter of terminating the wire leads.

    The shield does block some types of noise without a low impedance at RF connection to ground, but for other types of noise the shield has to be properly prepared and connected to a shielded modular connector or jack.
  • JohnNY
    JohnNY Member Posts: 3,230
    Received, @Gary Jansen_4 !! Thanks a million! I hope I can do something for you some day.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
    Classes

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