Gulf Island Off-Grid System - Part 5 (Surge Suppression)

David and Laura · September 2013

One of the remaining items on the list for our new solar system is surge suppression. We rarely have lightning, but when it happens, it can be quite spectacular and intense.

We figure that we're at risk of transient surges due to two factors:

Our solar array is on a ridge at a high point.
We have some pretty long AC cable runs (500 feet to building 1, 500 feet to building 2, and 250 feet to the array)

Here's what we're looking at installing, and we wanted some feedback to see if this is sufficient levels of protection.

To protect the solar panels, both strings will be connected to ground through a Midnight MNSPD600.
To protect the AC side of the inverters located under the panels, a Midnight MNSPD300 will be installed into the panel AC load centre.
To protect the AC systems in the container (Sunny Island, etc), a Square D TVSS will be installed connected to the main AC load centre.
To protect the AC systems in each of the two buildings, a MNSPD300 will be installed at the service panel of each building.
For data communication, Ethernet cable is protected using a B&B Ethernet Surge Suppressor, and RS-485 runs will be protected using a B&B RS-485 Surge Suppressor.

Still "yet-to-spec" is a phone line surge suppressor.

So, our questions are:

Is this sufficient? There will be a SPD at each end of each long cable run.
Do we need protection at each end of each data run? In the past, I've typically seen it only installed on the "more expensive" end of each run.
Anything else that we might be missing?

Thanks!

BB. · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

Not my wallet--But I would install suppressors on both sides of long wire runs where they enter the buildings. You have the equipment you are protecting--And the people in the area too.

-Bill

westbranch · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

there are some threads over on the MidNIte site on SPD's and their choice and placement.

http://midniteforum.com/index.php?board=13.0

inetdog · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

David & Laura wrote: »

[*] Do we need protection at each end of each data run? In the past, I've typically seen it only installed on the "more expensive" end of each run.
[*] Anything else that we might be missing?
[/LIST]

Thanks!

Well, depends on how expensive the "less expensive" end is. A surge protector at the far end of a long data line will not protect semiconductors at the near end from pulse type surges.
So if the equipment directly connected to the data line costs more than the surge suppressor, OR will be hard to replace and is critical to the operation of the system, go ahead and add suppressor to both ends.

David and Laura · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

For the phone surge suppression, we're leaning towards this Sixnet product:

http://www.sixnet.com/dist/SP-TELCO_datasheet.pdf

They run for around $50 each.

Re #2, #4 - Given the feedback, we're also going to put protection on both ends of our RS-485 runs. Replacing an inverter isn't something that we'd like to do...

Re #3 - Not too much there that isn't already well covered on the NAWS forums...

David and Laura · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

The RS-485 surge suppressor is now installed, so our Sunny Island Inverters are protected.

attachment.php?attachmentid=5831

We also added a little box up at the solar array to hold the RS-485 and Ethernet protector that we will be installing.

attachment.php?attachmentid=5832

There is also a Midnight MNSPD300 installed in the load centre (but not visible in the photo).

Next trip: Installing the remainder of the Midnight SPDs, and the Square D TVSS.

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David and Laura · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

The Square D TVSS panel came in the mail, and it looks like the USPS dropped it! The upper flange is bent almost 90 degrees.

Drat.

Now I'm having to deal with their damaged shipment bureaucracy.

zoneblue · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

Theres a little Heizenberg uncertainty principle image forming in my mind when i look inside that box. Out of curiousity how much power does all that monitering gear actually draw?

David and Laura · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

Re #8 - Very very little, under 1/3 of an amp at 48 volts. I'll clamp it and get you an exact measurement, as it's something on the to-do list.

Surfpath · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

Hi D&L,
Very well researched project you have in motion.

Re. lightning surge protection, have you installed your hydro and if so, how do you protect your (presumably long) Hydro cable run? How has your experience with Hydro been in general?

David and Laura · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

Re #10 - Our cabin system has a small Harris waterwheel connected with a very long power cable. The waterwheel puts out around a hundred volts, which is stepped down to close to 24 volts, regulated, and connected to the battery. It's part of an older setup that we inherited when we purchased the property, and isn't very well protected. But because it is connected to the battery, it does have a (slightly) higher ability to withstand a surge.

Since that's on our smaller system, we haven't done a full lightning surge assessment like we have with our new system. It has some older Delta protectors that we may want to replace with Midnite SPCs too.

Our existing wheel puts out 200 watts 24/7 during the winter months, and really helps keep the battery topped up when we have weeks (or months) of clouds and rain). We're looking at replacing it with a PowerSpout ME 250 or PowerSpout GE400, but that would be a project for the next year or the year after. This winter, when we have water again, we'll measure the pressure so that we know exactly how much power potential we actually have.

David and Laura · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

We weren't too happy with the B&B RS-485 surge protector we have installed, so we ordered a set of Dehn BLITZDUCTOR BVT RS485 SPDs to replace it and provide protection on both ends of the RS-485 line.

http://www.dehn-usa.com/pdf/Cat2005/pgs%20176-181%20Blitzductor%20VT.pdf

This is a much nicer product from a mounting and termination standpoint, and has better specs.

David and Laura · September 2013

Re: Gulf Island Off-Grid System - Part 5 (Surge Suppression)

The Square D TVSS is now installed and operational:

attachment.php?attachmentid=5916

We also have DC protection installed at the solar array:

attachment.php?attachmentid=5915

That completes the installation of the surge suppression equipment. While this won't help us if there is a direct lightning strike to our system, it should reduce the probability of damage from a nearby strike.

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Gulf Island Off-Grid System - Part 5 (Surge Suppression)

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