Disadvantages to using last gen SMA SB6000-US-10 inverters?

[Spektre]

I found the older, last generation SMA SB6000-US-10 for a really good price. I know several of its disadvantages are:

- no integrated AFCI
- no secure power
- bigger and heavier due to transformer
- only single MPPT
- no built-in communication module

I have no shading issues at all, didn't really think the secure power was all that useful, don't care about the weight... so, how much extra expense am I looking at to add AFCI and the comms module? I believe AFCI became a requirement under NEC 2014, correct?

Also, is it correct to say the module wiring is different between transformer/transformerless inverters? If true, what is that difference?

[sensij]

Also, is it correct to say the module wiring is different between transformer/transformerless inverters? If true, what is that difference?

Grounding is different, since one of the system conductors in the -10 model must be grounded, while the TL series is ungrounded. That affects how the ground wire is sized and run (GEC vs EGC), and also the insulation color of the grounded system conductor is supposed to be white, vs non-white for the ungrounded system.

Ground fault protection is much more sensitive for the TL series, as well.

[Spektre]

Grounding is different, since one of the system conductors in the -10 model must be grounded, while the TL series is ungrounded. That affects how the ground wire is sized and run (GEC vs EGC), and also the insulation color of the grounded system conductor is supposed to be white, vs non-white for the ungrounded system.

Ground fault protection is much more sensitive for the TL series, as well.

Thanks for the answer Sensij.

So the extra grounding wire doesn't really sound like that big a deal as far as install expense. When you say ground fault protection is much more sensitive for the TL series, are you saying it better at sensing ground faults or more often triggers because it's too sensitive to ground faults?

Do you have any experience adding AFCI to the older inverters? I know they sell a separate AFCI box to add to systems, and I think its required for new installs.

[adoublee]

Are you addressing rapid shutdown separately or haven't had 2014 NEC adopted yet?

[solarix]

go for it.