Ground terminal for PSPV

Discussion about the Power System PV Combiner (PSPV)

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Anonymous

Ground terminal for PSPV

Post by Anonymous » Thu Apr 04, 2002 9:29 am

Is the ground terminal provided with the PSPV listed for landing more than one conductor? Was this stated in the literature and I missed it.

Paul

Christopher

Ground terminal for PSPV

Post by Christopher » Wed Apr 10, 2002 10:04 pm

The ground lug in the PSPV is rated for only one conductor - the OBPV breakers used in systems up to 125 vdc are rated for two wires.

The PSPV includes only one ground lug standard. There is mounting locations for up to three of the ground lugs - two on the back surface and one in the bottom which can be either internally or externally installed. You can also add one of the GBB (Ground Bus Bar) kits if more ground terminals are required.

The ground terminal lug is the same as what we provide on the positive busbars - two are included. If you are not using the combiner for two sperate output circuits, one of the terminals can be reused as a ground terminal by removing it from the busbar and installing it in one of the square holes in the chassis.

Kent Osterberg
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Ground terminal for PSPV

Post by Kent Osterberg » Tue May 18, 2004 8:33 pm

How about adding predrilled holes for the GBB?
There are predrilled holes for the TBB, but not for a GBB. Why is that?

Robin Gudgel

Ground terminal for PSPV

Post by Robin Gudgel » Fri May 21, 2004 6:18 am

It is fairly common for people to split the PSPV into two circuits. Some controllers like the SB require separate negative circuits. When we designed the PSPV, the SB was the preferred MPPT available. With its lower current rating we were seeing many of these units per system, so we made holes for the second TBB. Very seldom are people adding a GBB into the box. If we ad another hole or a set of holes, then there will be more holes to plug when not using them. These boxes are often put outside in the rain so holes need to be plugged. No matter what we do, it will not satisfy all installations. We tried to make it work for the majority of cases. If more people want the extra holes, then speak up and I'll add them. To add a GBB, drill .172 diameter holes. Our thread forming screws that come with the GBB will go right in and tighten up.

Kent Osterberg
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Ground terminal for PSPV

Post by Kent Osterberg » Fri May 21, 2004 7:46 am

Robin, I agree that unused holes should be plugged -- keeps the rain out and helps to keep the wasps out too. Since most of the combiners are put in without a second TBB, the job of plugging holes needs to be done anyway. The newer boxes have multiple square holes for the ground lug that should also be plugged. A couple more holes to plug will not make that job significantly bigger, but it will make it easier to install the GBB.

I believe that the GBB belongs in almost every PSPV! Here's a list of the ground wires that should land in a typical PSPV installation for a pole-top mounted array:
1. with the output wires
2. to a ground rod at the array
3. to the modules
4. to the pole (structural steel)
5. to a second (possibly future) array
It's possible that one ground wire can serve for multiple items on this list, but the provided ground lug really isn't sufficient.

Also, the GBB isn't mentioned in the catalog as an accessory for the PSPV. Is that because it won't fit without drilling the box?

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Post by DavidB » Sun Nov 13, 2005 10:48 am

I have an older PSPV and was wondering if there have been any modifications to address the issue Kent brought up. Since the lugs are not rated for more than 2 wires then it would seem you would run out of ground locations quite often. I noticed in a recent Home Power article that did use one of the lugs to terminate 2 ground connections. A followup in a the latest Home Power commented on how this was a red flag.

Mine came with three box lugs. 2 on the +breaker bus bar and 1 for the ground. If you use a delta surge arrestor which I would think is fairly common and have top-of-pole mount you would have:
- ground wire to ground rod
- ground wire to array
- ground wire from arrestor

The positive breaker bus bar would also use one lug for cable back to controller and one lug to attach the + arrestor wire to. So looks like 5 connections with only 3 lugs.

Along these lines, I wanted to make sure the positive wire from the delta arrestor should be connected to the breaker bus bar, is this correct?

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