[RE-wrenches] Accessibility of Equipment on Roof was Are PV Systems Mechanical Equipment?

[Jason Szumlanski]

Yeah, normally it would have been our practice to use a j-box and bring
down three strings. In this case it made more sense to combine strings on
the roof and just bring down a single circuit in a single conduit. Long
story... long wire run... probably bad planning in hindsight.

The MNPV6-AC is a new product with a disconnect on the front exterior and
up to six breakers on a DIN rail that you can combine with bus bars that
they supply. It is specifically for combining AC strings. I think it's
rated for 120A per pole. I'm impressed with the units. It makes a great
residential Enphase string combiner.

List price is $239.00 and it's on their site as the last item here:
http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=34&productCatName=PV%20Disconnecting%20Combiners%20-Not%20Birdhouse%20Compatible

You are right - jurisdictions around here do not require disconnects on the
roof. The AC connectors on the inverters suffice. We normally just do a
j-box and transition to THWN. We've been using TC-ER to extend the trunk
lines and just use one j-box with all circuits running down a single
conduit to whatever combiner we need or to the load center for smaller
systems. No utility discos <10kW here. Yay!

*Jason Szumlanski** *

*Fafco Solar*

*
*


On Fri, Feb 8, 2013 at 11:11 AM, jay peltz <jay at asis.com> wrote:

> Hi jason,
>
> 3 questions,
> I can't find the MNPV-AC in midnites price list, is this something custom
> or just new?
> And
> if you don't need breakers why not just do a junction box on the roof.
> and
> the inspectors I've had have requested a disconnecting means on the roof
> or visible from the roof.  So I've done the enphase suggested switches on
> the roof, but no overcurrent.  It doesn't appear that is a requirement from
> your inspector?
>
>
> jay
>
> peltz power
>
>
> On Feb 8, 2013, at 7:27 AM, Jason Szumlanski wrote:
>
> Oh, yes - that is a great application for the MNPV-AC. I didn't mean to
> imply there isn't a good use for them. In this particular instance the
> three MVPV-AC's are really subcombiners that get all get tied together in
> another subpanel at ground level. They really were not necessary, but made
> it more convenient and cost effective.
>
> It's just interesting how Midnite advertises that they can be mounted as
> flat as a 3:12 pitch. What application would allow this mounting angle
> where it is still readily accessible? The spec/advertising seems to imply
> that these can be roof mounted in an AC string combining application.
>
> The Soladeck combiner with fuses would appear to be non-code compliant in
> any situation. I would love for someone to refute that in a convincing way
> given the access requirements in 240.24(A).
>
> *Jason Szumlanski*
> *Fafco Solar*
>
>
> On Thu, Feb 7, 2013 at 7:31 PM, jay peltz <jay at asis.com> wrote:
>
>> Hi Jason,
>>
>> Is it possible to install them on the side of a building?
>> And Dan's suggestion for the remote midnite might be perfect.
>>
>> jay
>>
>>
>> On Feb 7, 2013, at 3:55 PM, Jason Szumlanski wrote:
>>
>> Jay,
>>
>> I assume you mean pitched roofs, or not readily accessible flat roofs.
>> This particular project happens to be a flat commercial roof, but with no
>> permanent ladder or hatch. I really didn't have to use the MNPV6-AC's, but
>> it made sense in this case (excluding the access issue).
>>
>> Looks like my options are to remove the combiners or install a permanent
>> access. Neither are fun options. Live and learn...
>>
>> *Jason Szumlanski** *
>> *Fafco Solar*
>>
>>
>
>
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