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Class 4 digital wiring

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hot_rod
hot_rod Member Posts: 27,707
in THE MAIN WALL

Interesting article. Seems as more equipment has ECM/DC motors, pumps, compressors, most LED lighting. Sending DC directly to the equipment makes sense. High voltage, small conductor wire, no conduit.

https://www.phcppros.com/articles/23302-the-digital-electricity-revolution-why-class-4-wiring-is-the-secret-weapon-for-geothermal-retrofits

Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
PC7060Mad Dog_2EdTheHeaterMan

Comments

  • PC7060
    PC7060 Member Posts: 1,830
    edited May 24

    very interesting. “bundled” pulses of high voltage DC controlled by health checks every 20ms. Does the consuming equipment have a capacitive filtering to smooth out the gaps or are pulses invisible to the DC motors?

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,394

    May be a great Idea but it made me laugh.

    Low voltage technicians because the electricians are retiring

    Everything in the standard electrical world is referred to as heavy, expensive, costly and labor intensive

    I guess I am not smart enough to understand what you can run with DC @450 volts with wire that small.

    I thought Westinghouse beat out Edison (AC versus DC) because with DC voltage drop was the issue.

    I looked in the new 2026 NEC and it doesn't say too much about Class 4. Looks like #6 wire is the largest allowed. I am amazed that they will allow class 4 (450 v DC) wire in the same cable as a class @2 circuit like your doorbell or thermostat. Apparently, they have some Majic protection built into this stuff so you can't get shocked

    I equate this to gas piping.

    Do you want something that has been proven to last even though it is heavy, expensive or labor intensive and is safe? Like black pipe?

    Or do you want CSST which is cheaper but is as flimsy as tin foil and hope nothing goes wrong?

    109A_5Mad Dog_2EdTheHeaterMan
  • mattmia2
    mattmia2 Member Posts: 17,212
    edited May 24

    ac vs dc doesn't have different voltage drop at least at low frequencies. ac is easier to use for long distance power transmission so you can raise the voltage and lower the current to reduce the voltage drop and power loss because you have less current. you can use a transformer to change the voltage/current combination. it is much more complicated to do that with dc.

    it sounds like it will fail spectacularly not because it is a bad idea but because it will be done as cheaply as possible.

    pex doesn't replace iron pipe, the things that iron pipe was used for recently still needs iron pipe.

    you will have the conversion losses at he transmitter and receiver, you would have to use a dc-dc converter at both ends to make what you need which usually involves providing chopped dc to an inductor or transformer then rectifying and filtering it. the loss of that is why network switches need like 20a 208 ckts and a couple tons of cooling in the closet

    PC7060

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