[RE-wrenches] Cat 5 cable in 240 AC power conduit with #2 alum entrance wire.

[penobscotsolar at midmaine.com]

Very simply, is this not contrary to the NEC? I did not think we could run
wires of differing voltages in the same conduit. This is your CYA to the
client.

Daryl




> Well, I don’t think anyone on this list is a network specialist, which
> is what I would consider an expert…. But…
>
>
>
> Running cat5 (really any data cable) parallel to a power line (especially
> and AC line) is listed as a bad move in almost every installation guide I
> have ever seen. Data and power are supposed to cross paths in a
> perpendicular fashion whenever they get “close” to each other. If the
> clients wants to pay for a letter from a network specialist, just so they
> can spend more money putting the right stuff in, I would just have that
> done. But everything I’ve ever learned about this says that power
> running in the same conduit as communications is a cardinal sin (they run
> parallel, and as close as is physically possible while in the same
> conduit). To borrow a phrase from Joe Lstiburek “That’s what we call a
> Barry Bonds problem…..stupid on steroids”.
>
>
>
> The bare minimum is to make sure the cable is shielded, and the bleed wire
> is terminated at a grounding point at one end only. This is the only way
> there is a prayer for Ethernet signals to make the 120’ journey with any
> reliability. The more noise in the line, the slower the connection, as
> more and more packets will get rejected and have to be re-sent until they
> make it through without too much distortion, at some point the noise will
> prevent any data packets from making it from A to B and you need to break
> out the string and Dixie cups.
>
>
>
> The standard phone line may function, but it might sound like you’re
> talking to one of the adults from Charley Brown.
>
>
>
> As for the inverter signal…. I bet that would work if you use a solid
> state relay that requires just a few milliamps to trigger, even 28AWG cat
> 5 wire can handle that I bet. When we use a shielded cat 5 to transmit
> MODBUS and a small amount of signal power, we usually use two pairs of
> wire and parallel them just to give more copper for the amps to go
> through. You just make sure you run the + using the striped wires from
> both sets, and the - on the solid wire from both sets (or vise versa) so
> that your power is truly running in twisted pairs still and so it will not
> create any added noise in the cabling.
>
>
>
> When a client wants to do something like this with us and we cannot
> convince them it’s a bad idea, we simply put it in writing that any
> issues resulting from “XYZ” will not be covered by our warranty, as it
> was done counter to industry best practices, and against our advise.
>
>
>
> With Regards,
>
>
>
> Daniel Young,
>
> NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90
>
>
>
> From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On
> Behalf Of John Blittersdorf
> Sent: Monday, August 22, 2016 9:26 AM
> To: RE-wrenches <RE-wrenches at lists.re-wrenches.org>
> Subject: [RE-wrenches] Cat 5 cable in 240 AC power conduit with #2 alum
> entrance wire.
>
>
>
> Wrenches,
>
>   I have a customer who has pulled a cat 5 cable through his power conduit
> (2" PVC) to a new barn for about 120' and wants to use it for ethernet
> and telephone.  Wants me to use a pair if wires in the cable to trigger
> a relay to disconnect a direct grid tie inverter (AC Coupling) when
> batteries are full on his double GVFX3648 backup system   He wants it in
> writing from experts that it is not a good idea.  Has anyone done this
> and had good luck with it or have opinions?
>
>
>
> John Blittersdorf
>
>
>
> formerly owner of Central Vermont Solar & Wind
>
> now working for the new owner Rob Stubbins Solar
>
> (I get a regular paycheck and (usually) regular hours.
>
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