4 ms·

Can you please elaborate? Sadly your linked document is in Italian, which poses a language barrier for most of the community here.

bombcar 4y ago
Two problems - mains lines could come in contact with the data lines which would then transmit power to things connected to them (or burn up). Fiber won't do this because it doesn't transmit. And the second is that mains lines are AC and could introduce noise into the wired lines - again, fiber isn't susceptible to this.
jaclaz 4y ago
Until that norm (as said I believe around 2010 or so) you could NOT mix low voltage (and signal) cables with mains (220V-240V AC usually) within a same conduit. The new norm allows this mixing as long as the low voltage cables are certified as having insulation for 400 V. Still you cannot strip the cable (i.e. you cannot put a terminator/receptacle) in the same box as mains. The code is mainly about electrical safety, it doesn't consider the possibility of interference, that is "your" problem (but shielded cables give no problems in practice).
cptskippy 4y ago
The National Electric Code in the US has similar provisions: > 300.3 > (C) Conductors of Different Systems. > (1) 600 Volts, Nominal, or Less. Conductors of ac and dc > circuits, rated 600 volts, nominal, or less, shall be permitted > to occupy the same equipment wiring enclosure, cable, or > raceway. All conductors shall have an insulation rating > equal to at least the maximum circuit voltage applied to any > conductor within the enclosure, cable, or raceway. Basically idea is to prevent a low/less voltage cable from potentially being energized by a higher voltage cable. It would suck to strip the ends off your CAT6 and discover it's been energized to 240v.
- mindslight 4y ago
  But keep in mind many times electrical conduit is not used as a bona fide conduit, but rather more of a physical convenience (note how the bit you quoted is talking about conductors not cables. So if you bury a length of PVC pipe (grey or white) with a cat6 network cable plus a UF power cable (required for the wet location, regardless of the pipe), you're fine. Although residential in the US rarely (never?) goes above 170 volts (peak), which is more forgiving than the ~325V of most of the world.
  - cptskippy 4y ago
    A cable is at least one wire which is a conductor, they use the term conductor because the standard applies to more than wires and cables. Claiming a conduit is just a convenience doesn't change anything. Where did you get the 170/325 numbers? In residential applications it's 220-240v for most of the world. North America uses split phase for most outlets but major appliances still run on 220-240v.
    - mindslight 4y ago
      I think it's going to come down to the AHJ, or your own judgement if there is no inspection. The way I've seen it explained on electrician forums is that you're not using the piece of PVC for its properties as conduit under the electric code (like say outer damage protection/containment for running single THHNs), so it isn't considered a conduit. But it would obviously be wrong to apply this argument to things like conduit fill or abrasion protection - regardless whether the pipe was manufactured intended for electrical conduit or not. While they call mains voltage 120V, that's actually RMS voltage and not peak voltage. The peak is 170V, which I think is a better gauge for thinking about insulation and safety (by the time power is being resistively dissipated, you've already lost). Residential "240V" circuits use opposing legs of a split phase, so nothing is more than 170V from ground, which is what matters for insulation and most failure modes. You're not going to get any more of a shock from a "240V" residential circuit than a "120V" one unless you manage to touch both ungrounded conductors at the same time - it's the arc flash risk that gets worse. Although now that I'm really thinking about it, maybe mixing insulation types is not foolproof at the extremes. If there is a wire with 170V inside sitting in free space, the worst case assumption is that it can have 170V on the outside of its insulation as well (due to the parasitic resistance and capacitance across the insulation, and ignoring the parasitics to ground. If this sounds strange to you, think about how those non-contact voltage testers can work). So if you put a grounded conductor with a low insulation rating right next to it, that insulation could have voltage across it higher than its own rating (depending on its parasitic R/C), which may cause it to break down over time. The possibility is likely moot with real world values, but still.

bombcar 4y ago

Two problems - mains lines could come in contact with the data lines which would then transmit power to things connected to them (or burn up). Fiber won't do this because it doesn't transmit. And the second is that mains lines are AC and could introduce noise into the wired lines - again, fiber isn't susceptible to this.

jaclaz 4y ago

Until that norm (as said I believe around 2010 or so) you could NOT mix low voltage (and signal) cables with mains (220V-240V AC usually) within a same conduit. The new norm allows this mixing as long as the low voltage cables are certified as having insulation for 400 V. Still you cannot strip the cable (i.e. you cannot put a terminator/receptacle) in the same box as mains. The code is mainly about electrical safety, it doesn't consider the possibility of interference, that is "your" problem (but shielded cables give no problems in practice).

cptskippy 4y ago

The National Electric Code in the US has similar provisions: > 300.3 > (C) Conductors of Different Systems. > (1) 600 Volts, Nominal, or Less. Conductors of ac and dc > circuits, rated 600 volts, nominal, or less, shall be permitted > to occupy the same equipment wiring enclosure, cable, or > raceway. All conductors shall have an insulation rating > equal to at least the maximum circuit voltage applied to any > conductor within the enclosure, cable, or raceway. Basically idea is to prevent a low/less voltage cable from potentially being energized by a higher voltage cable. It would suck to strip the ends off your CAT6 and discover it's been energized to 240v.

mindslight 4y ago
But keep in mind many times electrical conduit is not used as a bona fide conduit, but rather more of a physical convenience (note how the bit you quoted is talking about conductors not cables. So if you bury a length of PVC pipe (grey or white) with a cat6 network cable plus a UF power cable (required for the wet location, regardless of the pipe), you're fine. Although residential in the US rarely (never?) goes above 170 volts (peak), which is more forgiving than the ~325V of most of the world.
- cptskippy 4y ago
  A cable is at least one wire which is a conductor, they use the term conductor because the standard applies to more than wires and cables. Claiming a conduit is just a convenience doesn't change anything. Where did you get the 170/325 numbers? In residential applications it's 220-240v for most of the world. North America uses split phase for most outlets but major appliances still run on 220-240v.
  - mindslight 4y ago
    I think it's going to come down to the AHJ, or your own judgement if there is no inspection. The way I've seen it explained on electrician forums is that you're not using the piece of PVC for its properties as conduit under the electric code (like say outer damage protection/containment for running single THHNs), so it isn't considered a conduit. But it would obviously be wrong to apply this argument to things like conduit fill or abrasion protection - regardless whether the pipe was manufactured intended for electrical conduit or not. While they call mains voltage 120V, that's actually RMS voltage and not peak voltage. The peak is 170V, which I think is a better gauge for thinking about insulation and safety (by the time power is being resistively dissipated, you've already lost). Residential "240V" circuits use opposing legs of a split phase, so nothing is more than 170V from ground, which is what matters for insulation and most failure modes. You're not going to get any more of a shock from a "240V" residential circuit than a "120V" one unless you manage to touch both ungrounded conductors at the same time - it's the arc flash risk that gets worse. Although now that I'm really thinking about it, maybe mixing insulation types is not foolproof at the extremes. If there is a wire with 170V inside sitting in free space, the worst case assumption is that it can have 170V on the outside of its insulation as well (due to the parasitic resistance and capacitance across the insulation, and ignoring the parasitics to ground. If this sounds strange to you, think about how those non-contact voltage testers can work). So if you put a grounded conductor with a low insulation rating right next to it, that insulation could have voltage across it higher than its own rating (depending on its parasitic R/C), which may cause it to break down over time. The possibility is likely moot with real world values, but still.