PS2 Clarifications

Discussion about OutBacks "PS" enclosures

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bflusche
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PS2 Clarifications

Post by bflusche »

I would like to clarify a couple of items in building a PS2 system:

1. Inverter grounding lugs. The wiring diagram shows them connected to ground. There are not any instructions about this. Should they be connected to a ground bar? If so what size wire, #8?

2. Cat5 communication cables to the inverters. Since the HUB is on the left side, the cables will come through the PS2AC into the inverter. No notching of the lexan cover is needed?

3. Best way to route the MATE RJ45 cable to the HUB. Just go thru the PS2DC, one inverter, and thru the PS2AC?

4. Master inverter. I have two VF3648s. Is there any preference as to which (bottom or top) is the master? Since the master is always on, any preference due to air flow or cooling?

5. I took out one to many square breaker slugs in the PS2DC cover. Any good solutions to cover the hole other than cutting some sheet aluminum and attaching with screws?
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mvrck
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Post by mvrck »

1. I use 6ga for everything inside the PS2AC and DC (except for Inverter-Battery-DC and battery to + Bus). Run the green wire from the inverter ground lug to the DC ground bus. Run the Inverter AC Ground wire from the AC side to the AC ground bus. Between the star washers and the extra wiring, should be covered.
2. Yes. Notch the cover for the RTS and CAT5 cable.
3. Yes.
4. I put (as most people have) L1 on top, L2 on bottom.
5. I bought a few extra 60A breakers for unknown future expansion. Just put another breaker in the hole. If you ever plan on getting more panels or a dc gen or any other unforeseen add-on, you will already have a breaker. For the purist, it might not be the right size. It will likely be used as a disconnect and the proper size breaker will be at the source of the DC. You could also get a 10A breaker and wire in a back up light source at the PS2 just in case.
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bflusche
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Post by bflusche »

Thanks. Two more questions on DC wiring shown in Fig 11 "PS2 Wiring Diagram::

6. I have an OBDC-GFP/2 installed. One of the 60 amp GFP breakers runs directly to an OBDC-60 and then to the solar array +V. Assuming the GFP-2 60 amp breaker functions as a normal overcurrent breaker in addition to the ground fault function, these two series breakers give "double breaker" protection. Why? Is it necessary or can the GFP-2 run directly to the array and save a breaker?

7. There is no disconnect between the battery bus and the +DC bus bar. While the only loads shown on the +DC are MX-60 with input breakers, is there any real advantage to adding a breaker between the Battery bus and the +DC bus?
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Post by mvrck »

6. I never examined the GFP that close to see if the two outside terminal were contacts or breakers. I know the center is the breaker looking for ground current. I kind of remember reading somewhere that your not supposed to use a GFP as a disconnect. That might be a figment of imagination...
7. The only reason would be if you had a bunch of DC loads and you wanted a easy way to disconnect all of them at once. Otherwise all the DC loads/sources are individually breakered.

Thanks
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Post by ericwahl »

mvrck wrote:6. I never examined the GFP that close to see if the two outside terminal were contacts or breakers. I know the center is the breaker looking for ground current. I kind of remember reading somewhere that your not supposed to use a GFP as a disconnect. That might be a figment of imagination...
Correct. If you do, the array negative is not bonded to ground while disconnected. Whether that is important to you is another question.
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Post by bflusche »

Revisiting item #3. This will mix high and low voltage wires in the breaker box and inverter and may be a problem for electrical permit inspections. Searching the internet for UL & NEC requirements, I don't see a lot of info about this specific issue.

The only UL info is dual gang Carlton brand receptical boxes that have a plate to separate the low voltage from the 120.

On the NEC side there is 725-54 which requires that the device be designed for and support simultaneous high voltage and low voltage plus other requiremetns.

While not specific there is some verbage about the NEC prohibiting running high & low voltage wires in the same conduit.

I don't see anything in the Outback spec sheets or manual that says the components are designed for this purpose. Anyone with experience in this area?

Thanks
Barney
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