GBB and TBB

Discussion about the Power System DC Disconnect (PSDC)

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ericwahl
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GBB and TBB

Post by ericwahl » Wed May 01, 2002 7:16 am

Hi,
Are the standard pos. and neg. bus bars for the PSDC the same as your separately available GBB and TBB?

What are wire size capacities for TBB and GBB?

Thank You!
Eric

ericwahl
Forum Guru
Posts: 132
Joined: Wed Mar 13, 2002 11:01 pm
My RE system: (9) SW230mono, XW-60-MPPT, SW5548
Contact:

GBB and TBB

Post by ericwahl » Thu May 02, 2002 11:15 am

Thanks Marty,
I haven't yet handled the PSDC, so I have more stupid questions - where would you terminate a 4/0 neg. battery cable? Is there a 4/0 lug attached to the GBB? And to continue on with 4/0 to the inverter?

For positive 4/0 battery input, I would either go to the 250 amp breaker and then to the TBB, or to the TBB and then to the breaker. Either way I don't understand how I can maintain 4/0 to the inverter and also make use of the TBB if it doesn't take 4/0? Or do you just switch to 1/0?

Sorry if this is painfully ignorant. I appreciate your help.

Eric

Christopher

GBB and TBB

Post by Christopher » Thu May 02, 2002 5:41 pm

The TBB and GBB are the same parts as used in the PSDC, PSAC and PSPV products. The TBB includes two of the black plastic insulators and mounting hardware and flexible plastic sheet insulation to prevent wires from contacting the side of the enclosure. The GBB only has mounting screws included.

Both the GBB and TBB allows three #1/0 to 14 AWG and eight #6 to 14 AWG wires. No lugs or crimp terminals are required for the connections.

We also now have the custom made insulators in red and white plastic in addition to the original black version. We can also provide a longer version of the TBB if needed.

The TBB with red insulators is PN TBB/R.
The TBB with white insulators is PN TBB/W.

The PSDC and PSAC can accept several additional TBBs and GBBs if required. One TBB is standard on the PSDC along with a combined negative/ground busbar connected to the chassis and shunt. The PSAC has two TBBs and one GBB standard.

The PSPV has one TBB standard and can accept one additional TBB. Two TBBs are needed when using one PSPV with two RV power products controllers as the negatives on the PV array side must be kept separate.

Christopher

GBB and TBB

Post by Christopher » Thu May 02, 2002 5:43 pm

The PSDC includes a 500 amp DC current shunt standard for connection of the negative battery and inverter cables. The terminals on the DC current shunt are 3/8" bolts that go into tapped holes into the shunt. The DC cables require either crimped-on lug terminals on the ends - but so do the positive cables on the breaker 3/8" threaded stud terminals.

The advantage of OutBack's PSDC design is that since all of the lage DC cables are connected with lugs with bolted terminals, you can connect multiple wires per terminal easily. This allows you to "tap" off of the battery connection from one breaker with a short cable to feed another breaker or the TBB. Our distributors all make up custom cables or stock several standard sizes that will work well for various configurations.

The standard TBB in the PSDC can be used for either input or load circuits - so it is not connected to anything from the factory. The size of wire used to connect the TBB depends upon the amount of current involved, but up to #1/0 is accepted by the TBB. A ring terminal on one end of the wire is usually needed to connect this "tap" conductor to one of the large DC breakers. It is acceptable to make short jumpers of smaller gauge wires from a high current circuit as long as the circuit stays inside of the PSDC or goes through an appropriately sized breaker for the wire size before it leaves the enclosure or supplies another component like a relay or controller.

We have example diagrams in the documentation section of our website which might help you visualize the connections.

<small>[ May 02, 2002, 08:08 PM: Message edited by: Christopher Freitas ]</small>

ericwahl
Forum Guru
Posts: 132
Joined: Wed Mar 13, 2002 11:01 pm
My RE system: (9) SW230mono, XW-60-MPPT, SW5548
Contact:

GBB and TBB

Post by ericwahl » Thu May 02, 2002 6:46 pm

Thanks Christopher,
Your response plus the Halakau diagram clears it up nicely. I think the 3/8" lugs is a great idea.

Eric

Christopher

GBB and TBB

Post by Christopher » Fri May 03, 2002 2:11 pm

I agree - the 3/8" lugs work out very well for multiple cable and wire terminations. Eliminates the need most of the time for large copper busses and additional cabling.

Currently, the small and medium breakers (up to 60 amps) all have 1/4" studs. We also will soon offer a 125 amp breaker with 5/16" studs as well. It will fit in the medium size openings which are mixed with the large breakers (up to 4 large breakers or 6 medium breakers or 2 large and 3 medium breakers etc.).

<small>[ May 03, 2002, 04:12 PM: Message edited by: Christopher Freitas ]</small>

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