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

[Dan Fink]

If the PV home runs are below 600V, you shouuld be OK using 600V CAT 5 as
far as NEC 300.3(C)(1) goes.
But it sounds to me like an RFI / noisy signal nightmare on the CAT 5
waiting to happen.

This Blackout Relay scheme for preventing battery overcharge when AC
coupling is not optimal...it provides only 1-stage battery charging, 5
minutes in bulk then 5 minutes off (UL1741). Much better to use a diversion
load controller and diversion load for 3-stage charging, though with a
large PV array that can get expensive fast. Or SMA
sunny-boy/sunny-boy/sunny-island clusters which can do 3-stage by frequency
shifting, but he already has Outback.

I guess it boils down to how often there are grid blackouts. If they are
rare and short, 1-stage charging shouldn't hurt anything. If he's prepping
for the end of the world as we know it, he should go the diversion
controller route IMO.


Dan Fink
Adjunct Professor of Solar Energy Technology, Ecotech Institute
IREC Certified Instructor™ for:
~ PV Installation Professional
~ Small Wind Installer
Executive Director, Buckville Energy
NABCEP Registered Continuing Education Providers™
970.672.4342



On Mon, Aug 22, 2016 at 7:25 AM, John Blittersdorf <
john.blittersdorf at gmail.com> wrote:

> 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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