New Code Requirements

[J.P.M.]

And solar powered, once the snow is off the panels....

I'm just sayin', ya' know ??

[bcroe]

Suggestions & Chicago

Hearing about all the snow and bitter cold makes me glad I
moved out here from Chicago area. Don't miss the snow one bit.

Maybe you could invent a solar panel add-on device that has multiple functions. Mini
snow plow leading edge & retractable cover! Could cover both sides. Maybe put some
water jets in there to wash the panels off (when its not freezing, of course) -- even
a soft, non-scratching brush. Flame retardant material.... Non-slip, non-conductive
surface to keep the fire fighters safe? The possibilities are endless.

Thanks for all the innovative suggestions. There are a coupe months of the year not
so great here in the "wild west", but there is a long list of reasons some don't want
to live elsewhere. 4" of snow and we yawn, look at Atlanta!

Looks like the solution to snow is vertical elevation. Most times that works, or just
the slightest snow sticks. If the panels were vertical, just a little heat would cause
the snow to slide off; wonder how to do that? Melting the snow is out of range. We
have enough precipitation here to do the cleaning.

As just pointed out to me, the 2014 version of PVWatts indeed will give hourly output.
The data prints out on 250 pages (is my ink cartridge that big?), but capturing about
4 days over the year (and no nights!) will be enough info. When some curves get
worked out, will start another thread.

Not worried about firemen, with panels hundreds of feet from a building. Complete
overcast today, running only 2 or 3 KW. Then some snow, dropped to 800 W. The
vertical panels were completely clean. Cleaned the sloping panels at 15:30, got
back my 2 KW. Bruce Roe

[Mike90250]

How about heated glass like window defrosters?

I think Midnight is coming out with Ice Melter option in the software, it removes the anti-backfeed diode function, and lets the batteries heat the panels. I think it's best to run the generator with it !

[Solarisolator NZ]

Remote Solar Isolator

Hi, I'm a newb to this site and reasonably new to the solar scene here down under in New Zealand. I have been following this thread with interest especially with regard to comments about a pending new code that may enforce array isolation to a module level to ensure ELV on the roof top for reasons of maintenance access, reduced fire risk and most importantly safer conditions for emergency personnel. I note there are some creative suggestions about how to do this and wondered if you have heard of the Remote Solar Isolator which is product currently being used in Australia and we are introducing it to New Zealand. In essence, in layman's talk, the Remote Solar Isolator is different in that it tackles the problem of DC isolation at the source before the panels combine to lethal d.c voltages. The (RSI) is capable of simultaneously isolating solar panels, stopping the combining of panel voltages and limiting the system voltage to the safety of Extra Low Voltage. This disconnection can be performed either at the switchboard, or remotely by disconnecting the supply voltage. The engineered RSI is the only isolating system that provides the:

- Ability to switch off both locally and remotely.
- Defined isolating air gap between combining panels (Safest Isolation)
- Ability to clearly indicate safe solar panel isolation via existing inverter
- Ability to switch off when a predetermined temperature has been reached (if heat is detected from a fire the entire system will safely shut down).
- Ability to shut down solar generation independent from the solar panels
- Simply Retrofitted to any new or existing system.
- Cost effective and safe.

I would be interested in your feedback.

[inetdog]

All of those points are potentially valuable features.
For the 2014 NEC requirements not all of them are mandatory, but they are allowed as extra benefits.
For the moment the only module level isolation products that I have seen sold in the US are DC combiners incorporating Rapid Shutdown, microinverters (which do not need to actually do anything on the DC side because they are so close to the panel), and optimizers which are network controlled from the matching string inverter.
Any US solution will be better received if it also incorporates DC arc fault detection that can be used with existing string inverters that do not have this feature built in.

[Naptown]

Compliance for this would simply mean a combiner/ disconnect located within 10 feet of the array.
There is no requirement written as to the placement of or access ability of the shut down device.
That however leaves it open to interpretation.

[Naptown]

The one AHJ that has adopted this has allowed for a limited time a disconnect on the roof.
Seems after this it will require something remotely operated.
The only one on the current market I know about for grid tie is solar edge for a reasonable cost. Midnight has some compliant products but are very expensive.

[inetdog]

The one AHJ that has adopted this has allowed for a limited time a disconnect on the roof.
Seems after this it will require something remotely operated.
The only one on the current market I know about for grid tie is solar edge for a reasonable cost. Midnight has some compliant products but are very expensive.

There is at least one maker of a DC combiner with remote shutdown relays (not MN) but I do not remember the name. Basically DC breakers with shunt trip AFAIK, so you have to reset them by hand after the event is over.

[bcroe]

There is at least one maker of a DC combiner with remote shutdown relays (not MN) but I do not remember the name. Basically DC breakers with shunt trip AFAIK, so you have to reset them by hand after the event is over.

I presume that none of this will apply to ground mount panels, so there is going to be a price
advantage for them. 2 types of panels, if the fix is built into them, for roofs & ground.

I'm still pushing for a shorting relay (solid stated preferred) built into the panel, which will
default to shorting the panel. It will need a signal to enable the panels. Bruce Roe

[inetdog]

I presume that none of this will apply to ground mount panels, so there is going to be a price
advantage for them. 2 types of panels, if the fix is built into them, for roofs & ground.

I'm still pushing for a shorting relay (solid stated preferred) built into the panel, which will
default to shorting the panel. It will need a signal to enable the panels. Bruce Roe

All of this would, IMHO, apply equally well to ground mount panels. They would have to have a shutdown point within 10 feet of the outside limits of the array unless the inverter is within that 10' limit.
The goal is not to protect fire fighters specifically on your roof but working anywhere on your property.

[bcroe]

All of this would, IMHO, apply equally well to ground mount panels. They would have to have a shutdown point within 10 feet of the outside limits of the array unless the inverter is within that 10' limit.
The goal is not to protect fire fighters specifically on your roof but working anywhere on your property.

There are outside DC shutdown switches which completely disconnect anything in the building
(the inverters) from the ground mount panels, 230' away. There is nothing near the panels
that requires protection. So I see no need for disabling these panels. Bruce Roe

[Colt45]

Is is for systems on a building only. They don't care about pole or ground mounted arrays / equipment. They will just let that sucker burn!

690.12 Rapid Shutdown of PV System on Buildings.
PV circuits installed on or in buildings shall include
a rapid shutdown function that controls specific conductors
in accordance with 690.12(1) through (5) as follows.

1. Requirements for controlled conductors shall apply only to PV system conductors of more than 1.5m (5 ft) in length inside a building, or 3m (10 ft ) from a PV array.
2. Controlled conductors shall be limited to not more than 30 volts and 240 volt-amperes within 10 seconds of rapid shutdown initiation.
3. Voltage and power shall be measured between any two conductors and between any conductor and ground.
4. The rapid shutdown initiation methods shall be labeled in accordance with 690.56(B).
5. Equipment that performs the rapid shutdown shall be listed and identified.

[Solarisolator NZ]

I suggest it should apply to ground and roof as well. The aim is to provide safety for all whether its fire personnel or an over curious child. The beauty of using the Remote Solar Isolator is it has the following features:

Provides a single source solution that exceeds requirements for compliance of NEC 690.12.
Uses the latest air gap isolation techniques providing up to 8mm air gap in less than 5 milliseconds
Provides true instantaneous module level shut down isolation.
Removes lethal d.c. Voltages on any solar array providing a safe environment for all
Automatically shuts down if it detects heat from a fire
Prevents solar panels back feeding into the grid.
Allows emergency services an immediate and unrestricted path to attack a fire or emergency situation rather than lose precious time performing risk assessments or not be willing to go on the roof from concern of electric shock.
Electricians would be able to work on the array and change faulty solar panels or cables knowing that NO dangerous or lethal voltage can be generated.
Anyone would have safe access to work on or just near the array without fear of finding themselves in a hazardous situation caused by a hidden or unknown fault or damage to the array.
Prevents potential for electric shock when cleaning solar panels with water

Having this level of safety is peace of mind don't you think.

[SunEagle]

I suggest it should apply to ground and roof as well. The aim is to provide safety for all whether its fire personnel or an over curious child. The beauty of using the Remote Solar Isolator is it has the following features:

Provides a single source solution that exceeds requirements for compliance of NEC 690.12.
Uses the latest air gap isolation techniques providing up to 8mm air gap in less than 5 milliseconds
Provides true instantaneous module level shut down isolation.
Removes lethal d.c. Voltages on any solar array providing a safe environment for all
Automatically shuts down if it detects heat from a fire
Prevents solar panels back feeding into the grid.
Allows emergency services an immediate and unrestricted path to attack a fire or emergency situation rather than lose precious time performing risk assessments or not be willing to go on the roof from concern of electric shock.
Electricians would be able to work on the array and change faulty solar panels or cables knowing that NO dangerous or lethal voltage can be generated.
Anyone would have safe access to work on or just near the array without fear of finding themselves in a hazardous situation caused by a hidden or unknown fault or damage to the array.
Prevents potential for electric shock when cleaning solar panels with water

Having this level of safety is peace of mind don't you think.

Keeping people safe is a good thing and I support it.

What concerns me is what will the new regulation do to the cost of a system. And will existing systems be required to make hardware changes to meet the new regulation or will there be a grandfather clause?

[inetdog]

Keeping people safe is a good thing and I support it.

What concerns me is what will the new regulation do to the cost of a system. And will existing systems be required to make hardware changes to meet the new regulation or will there be a grandfather clause?

Pretty much standard that an existing compliant system is OK until you make substantial (or sometimes trivial) changes to it. The change event may trigger applying the current code to the old system.