Author Topic: Spyder only, no CT? Also, CT/Spyder max wire length?  (Read 749 times)

swillden

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Spyder only, no CT? Also, CT/Spyder max wire length?
« on: January 18, 2018, 12:33:50 PM »
I have two breaker panels in my house. One of them is large, with many circuits. On that one I want an MTU + CTs to track all usage, and a Spyder (probably mix) to get more detailed information about certain loads. The other one is small, with a total of six circuits.  I'm thinking that with one MTU + Spyder, I can track all of the usage there, with no need for CTs on the main input lines.

Is that possible? Can the system be configured to read from a Spyder that does not "break out" usage from a main CT pair, but instead provides the only measurement?

Also, how far from CTs/Spyders can MTUs be?  I could avoid purchasing an extra MTU if I ran long wires.  The rectilinear distance between the panels, following walls where I could mount cables, is a little under 60 feet.  So I could put the MTU by the large panel and run 60' wires to CTs/Spyder in the small panel, or put the MTU midway between them and run 30' wires each way. The effort of running the wires isn't a factor, since I'm going to have to run ethernet along that same route anyway (the router is near the large panel).  Using your wire extensions, I'd need three packs -- $45, vs an extra MTU, which is $99. Or if I made my own wire extensions I could do it more cheaply.  If 60' is too far with your wire extensions, would extensions with heavier gauge wire to lower resistance work? Or if interference rather than resistance is the issue, could I twist them to reduce interference?

Thanks.

pfletch101

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Re: Spyder only, no CT? Also, CT/Spyder max wire length?
« Reply #1 on: January 18, 2018, 05:09:53 PM »
You may want to raise a ticket (http://www.theenergydetective.com/ticket) to get a definitive answer on this. I suspect, however, that the answer will be that the distances are too long to run Spyder cables between your two panels (or from a central point to each panel). There are also code and safety considerations which (IMHO) would preclude this approach unless (possibly) you ran everything in conduit, which would certainly make your proposed approach much more difficult and expensive than buying a second MTU set. BTW, assuming that you have a reasonable WiFi setup, you shouldn't need to pull Ethernet cable, even if PLC transmission between your breaker box and your router location turns out to be iffy. I have my ECC plugged in to a dedicated circuit right next to my breaker box and networked via a WiFi Access Point plugged in next to it. The Access Point cost me about $20 from Frys.
Peter R. Fletcher
TED Pro Home - main MTUs monitoring utility and PV Solar feeds; 2 Spyders monitoring selected individual circuits

swillden

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Re: Spyder only, no CT? Also, CT/Spyder max wire length?
« Reply #2 on: January 18, 2018, 06:29:45 PM »
Thanks for the quick response.

I can't think what code or safety considerations would preclude the long run.  We're talking about low-voltage wiring, about which code (at least in my area) has nothing to say, and the route I have in mind would keep it safely out of the way so it wouldn't be any sort of physical hazard. Well, there may be some code issues with running the wiring out of the breaker enclosures, but that's going to be the same with any external installation, regardless of distance.

Am I missing something?

I'll raise a ticket; didn't realize that official support personnel weren't on this forum.

Thanks again!

pfletch101

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Re: Spyder only, no CT? Also, CT/Spyder max wire length?
« Reply #3 on: January 19, 2018, 10:13:55 AM »
Thanks for the quick response.

I can't think what code or safety considerations would preclude the long run.  We're talking about low-voltage wiring, about which code (at least in my area) has nothing to say, and the route I have in mind would keep it safely out of the way so it wouldn't be any sort of physical hazard. Well, there may be some code issues with running the wiring out of the breaker enclosures, but that's going to be the same with any external installation, regardless of distance.

The code issues to which I was referring do indeed have to do with running the wiring outside the breaker enclosures. By design, all TED hardware and wiring is/are intended to be installed within a single breaker enclosure. For your situation, I would envisage two separate 'installations'.

Quote
I'll raise a ticket; didn't realize that official support personnel weren't on this forum.

They do pass by quite frequently, but they aren't here every day. Tickets typically get a response within one working day.
Peter R. Fletcher
TED Pro Home - main MTUs monitoring utility and PV Solar feeds; 2 Spyders monitoring selected individual circuits