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Thread: New To Low Voltage, Is this allowed?

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    New To Low Voltage, Is this allowed?

    Have almost never worked with low voltage cable so fairly new to the rules around it, scenario is cat5e cable with POE 12VDC on it, i'm being told I can strap it along existing piping with tywraps because this type of cable isn't enforceable by CEC rules. It would be supported along insulated water lines, natural gas lines, and EMT as well as pass through some holes in concrete walls. Seems a little crazy to me cause I would almost always think the cable would need to be protected in some way and not just pulled in the quickest route possible and strapped to whatever works. Is low voltage above the rules in these cases?

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    I am not an electrician. The following comments are based on my 30+ years in the IT field, stringing cables in the computer room and beyond. What I and my colleagues did may have violated the NEC rules, but it was all done to provide as much protection to the cables as possible.

    Generally, you don't want communication lines running along side of power cables. This minimizes the comm lines picking up 60-cycle hummmmm. If either type of cable is in a metal conduit, this reduces the chances of induced hummmm.

    Normally, a few inches of space reduces the hummmm as well. If the comm lines must cross the power lines, doing so at a 90* angle is the generally recognized best way.

    You should check the CEC and see what the rules are for comm lines-- do they have to be in conduit, or can you just run them any which way? Fire code issues??

    As far as routing the cable-- In the USA, it's common practice to route comm lines almost anywhere. Restrictions apply when routing cables above suspended ceilings used as an air plenum-- cables must be plenum rated. And cables can't just be draped across the top of the suspended ceiling-- they must be supported, and not by the wires holding up the ceiling.

    You can't run cables through that nice, open air duct that leads from where you are to where the cable has to go. ): That's for air only!

    Other than that, protection from damage is the best advice I can give-- strapped to water pipes, you mentioned insulated. Don't disturb the asbestos insulation. (: And be careful of hot water (uninsulated)-- you don't want to roast the cables-- it ages them (and whatever is holding them together) prematurely.

    Running cables through a hole in the wall is OK; but watch out for fire-rated walls-- the penetrations have to be sealed with fire-rated fillers. The other issue is pulling the cable through the hole-- although cable jackets are remarkably tough, rough edges can be bad for the cable! Be gentle!

    Running comm lines into manufacturing areas you run the risk of 'accidental' damage. You have to provide protection to the lines-- and they must be supported. You don't want to see sagging cables overhead. Either a messenger wire or conduit or other means of support are required.

    Although dropping a comm line down to a workstation has been done, that's bad news, especially if someone gives a yank on the cable. Conduit or other protection is required! And, unless it's designed for it, just letting the conduit dangle from above is no good either. I'd be careful strapping cable to an electrical conduit as well-- it may be against the rules.

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    I've looked through the CEC a fair amount on the issue and none of it really talks about restrictions on installations, the comms section is fairly focused on keeping data away from power and the class 2 circuit section is similar. I've seen lots of low voltage installs that seem to go by the whatever works is fine and anything you do on top of that is just good practice but not an actual rule. As long as using existing piping systems as a support doesn't go against any building or plumbing rules its all good then?

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    See 725.143 & 800.133
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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    Quote Originally Posted by augie47 View Post
    See 725.143 & 800.133
    I don't have a copy of the NEC to look those up but this install is in Canada so it only matters whats in the CEC as far as I know.

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    opps missed the location.. cant help
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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    You can read up on 16-212, they require separation, but not when attached to EMT.

    If this a commercial install, most companies follow EIA/TIA standards.

    For resi installs, loosing a camera feed or internet is not a safety concern. My kids would argue with me on that though !

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    Quote Originally Posted by 414Mhz View Post
    You can read up on 16-212, they require separation, but not when attached to EMT.

    If this a commercial install, most companies follow EIA/TIA standards.

    For resi installs, loosing a camera feed or internet is not a safety concern. My kids would argue with me on that though !
    Ah missread that rule initially and thought it needed to be seperated from power conductors in emt, not that emt was suitable seperation. Its a commercial install for a cctv, main concern now is building codes against the natural gas line as a support.

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