# Can't shut this...



## ampman (Apr 2, 2009)

400 volt?


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## chicken steve (Mar 22, 2011)

Yeah, a dz cells made in series Amp ~CS~


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## 3xdad (Jan 25, 2011)




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## guest (Feb 21, 2009)

Couldn't you just have covered the panels with a tarp or something?


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## macmikeman (Jan 23, 2007)

Isn't there supposed to be a disconnecting means up on the roof when combiners are used instead of micro inverters? I've only installed micro inverter systems is why I ask, and they shut down the output when no utility voltage is present.


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## Rap2 (Dec 17, 2010)

macmikeman said:


> Isn't there supposed to be a disconnecting means up on the roof when combiners are used instead of micro inverters? I've only installed micro inverter systems is why I ask, and they shut down the output when no utility voltage is present.


Yes but the MC connector or whatever plugs into the panel is a means of disconnect and the combiner does not have to be on the roof


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## backstay (Feb 3, 2011)

macmikeman said:


> Isn't there supposed to be a disconnecting means up on the roof when combiners are used instead of micro inverters? I've only installed micro inverter systems is why I ask, and they shut down the output when no utility voltage is present.


Not until 2014. Now it must shut down PV conductors(reduce to not more than 30 volts) 10 ft from array or 5 ft inside of building. Called Rapid Shutdown. And don't use the MC connectors as a disconnect. They are not load rated.


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## backstay (Feb 3, 2011)

Here's a closeup. There is a box called a Bird House, with a button on it down at the inverter to remotely shut trip this disconnect. It's there for firefighters safety. Sorry about the sideways shot. The bird house talks too. Tells the world what the array status is.


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## backstay (Feb 3, 2011)

The bird house is right above the inverter.


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## Rap2 (Dec 17, 2010)

l


backstay said:


> Not until 2014. Now it must shut down PV conductors(reduce to not more than 30 volts) 10 ft from array or 5 ft inside of building. Called Rapid Shutdown. And don't use the MC connectors as a disconnect. They are not load rated.


 
OK for the times its 5 feet inside the building you should absolutely disconnect the MC connectors before servicing the Array after confirming its shut down and not under load.

Yes it is a plug and you shouldn't unplug any plug while under load.

Some MC connectors actually have that printed on them.


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## backstay (Feb 3, 2011)

Rap2 said:


> l
> 
> 
> OK for the times its 5 feet inside the building you should absolutely disconnect the MC connectors before servicing the Array after confirming its shut down and not under load.
> ...


You've never designed and installed a PV system have you? What service work would you be doing to an array?


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## Rap2 (Dec 17, 2010)

backstay said:


> You've never designed and installed a PV system have you? What service work would you be doing to an array?


I have designed and installed a couple.

As far as service work? How about changing a panel? Changing a failed optimizer under a panel? A faulty connection or wire? How about removing a panel to fix a leak in the roof?

What would you suggest to someone who designed a system with the Rapid Shut down 5 feet inside the building as a means of disconnect on the roof?

I believe you still need on in that case.


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## backstay (Feb 3, 2011)

Rap2 said:


> I have designed and installed a couple.
> 
> As far as service work? How about changing a panel? Changing a failed optimizer under a panel? A faulty connection or wire? How about removing a panel to fix a leak in the roof?
> 
> ...


I think you need to read the OP.


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## Rap2 (Dec 17, 2010)

backstay said:


> I think you need to read the OP.


Sorry to go off topic, was just responding to your question about what service you may preform on an array.

But I thought the question about putting the rapid disconnect inside was relevant.


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## chicken steve (Mar 22, 2011)

backstay said:


> Here's a closeup. There is a box called a Bird House, with a button on it down at the inverter to remotely shut trip this disconnect. It's there for firefighters safety. Sorry about the sideways shot. The bird house talks too. Tells the world what the array status is.


Backstay, what is that ? Midnightsun?Midnightsolar? 

and it talks?....it would  talk.....

~CS~


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## Meadow (Jan 14, 2011)

I knowing next to nothing about building a code complaint PV system. Back in the day when I designed them I went buy my own rules. I miss those days.


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## backstay (Feb 3, 2011)

chicken steve said:


> Backstay, what is that ? Midnightsun?Midnightsolar?
> 
> and it talks?....it would  talk.....
> 
> ~CS~


Midnite Solar is the brand I'm using. The disconnect has a circuit board with a RJ 45 connector, cat5 cable then goes between the disco and the Bird House. The Bird House can then monitor the disco's state. It talks about if the disco is open and when it is, it informs that power is still on or not at the array(sun is out). Or if the disco has failed somehow. It's pretty chatty, and it adds over $500 to the system.


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## chicken steve (Mar 22, 2011)

Thx, so this is all in 690.17 Backstay? 
I wonder if this (yesterdays gig) complies>>>:blink:?



















~CS~


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## backstay (Feb 3, 2011)

chicken steve said:


> Thx, so this is all in 690.17 Backstay?
> I wonder if this (yesterdays gig) complies>>>:blink:?
> 
> 
> ...


I have a bunch of Qs. Who's mount is it? I've never seen a meter in that location. We install a bidirectional meter at the service(the only meter). How many volts are the panels at? If it's over 50, you have to guard the wires and connectors. I haven't found any rack maker that has addressed that. I install the panels high enough to make them, not readily accessible(the wires). So mine are over 8 feet high. What's the second conduit at the pole for?


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## backstay (Feb 3, 2011)

Looks like micro inverters? How many watts and who's panels? Here's the back of the last one I did. All DC here. Panels are two sets in series. About 80 volts DC. It's not just 690, 705 also.


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## chicken steve (Mar 22, 2011)

backstay said:


> > I have a bunch of Qs. Who's mount is it?
> 
> 
> Well it's was installed via one of our local solar guru's, i really didn't catch the name brand, sorry
> ...


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## chicken steve (Mar 22, 2011)

backstay said:


> Looks like micro inverters? How many watts and who's panels? Here's the back of the last one I did. All DC here. Panels are two sets in series. About 80 volts DC. It's not just 690, 705 also.





> ARTICLE 705
> Interconnected Electric Power
> Production Sources


Hold my calls!......I've some reading to do.....~CS~


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## backstay (Feb 3, 2011)

The only time we install a second meter is to measure the usage of the site. That happens when the system is owned by someone other than the property owner. Property pays the PoCo the usage from the utility, the solar owner for the usage off the panels and the PoCo pays the solar owner the backfeed kWh.



chicken steve said:


> Hold my calls!......I've some reading to do.....~CS~


705 is not bad, I use option C for sizing, add up all the breakers except the main and stay under its rating.


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## macmikeman (Jan 23, 2007)

The following three pictures are from the 40 panel system tied to a single 100 amp (shared with a panel) main breaker that I spoke about. You judge for yourselves if it is a good idea to put 40x 240 rated panels onto a 1/0 feeder for a panel protected by a 100 amp breaker plugged onto a 200 amp rated bus.

























The fourth picture is of the identical new meter socket I picked up for this fix. I just swapped the busbar guts out of the new socket and installed them into the old socket since it was still in prime shape otherwise.


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## backstay (Feb 3, 2011)

macmikeman said:


> The following three pictures are from the 40 panel system tied to a single 100 amp (shared with a panel) main breaker that I spoke about. You judge for yourselves if it is a good idea to put 40x 240 rated panels onto a 1/0 feeder for a panel protected by a 100 amp breaker plugged onto a 200 amp rated bus.
> 
> 
> 
> ...


So you had a 40 amp inverter output protected with a 100 amp breaker?


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## macmikeman (Jan 23, 2007)

backstay said:


> So you had a 40 amp inverter output protected with a 100 amp breaker?


Not me, I wired that house for my wife's cousin. He asked me to do a pv but I wasn't interested at that time, so he brought in one of the big 5 locally. My meter/main has 4 spaces so you can run two ser cables from it to individual sub panels and put 2 100 amp disconnect breakers in the customer side of the can. The solar company tagged onto one of those 100 amp protected subfeeders just below the 100 amp breaker. I asked the poco trouble call lineman today as to how often he is seeing this stuff happen these days and he replied that it is daily now. I told him about the forty panels and he just shook his head.


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## backstay (Feb 3, 2011)

macmikeman said:


> Not me, I wired that house for my wife's cousin. He asked me to do a pv but I wasn't interested at that time, so he brought in one of the big 5 locally. My meter/main has 4 spaces so you can run two ser cables from it to individual sub panels and put 2 100 amp disconnect breakers in the customer side of the can. The solar company tagged onto one of those 100 amp protected subfeeders just below the 100 amp breaker. I asked the poco trouble call lineman today as to how often he is seeing this stuff happen these days and he replied that it is daily now. I told him about the forty panels and he just shook his head.


So you fixed it by just replacing the buss? Won't it happen again?


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## macmikeman (Jan 23, 2007)

backstay said:


> So you fixed it by just replacing the buss? Won't it happen again?


I took an alternate meter/main over there today that uses one single 200 amp breaker for a main, then has 20 spaces for additional breakers down the right side. My inlaw paid me for that meter, and told me he is going to have the solar guys come back and install it at their own cost. OR ELSE.


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## macmikeman (Jan 23, 2007)

Right now he is happy to have power. And I fixed him up in about twenty minutes once the poco guy pulled the meter out of the socket to de-energize. He has Koi in a pond inside his living room. Berry Berry expensive.


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## chicken steve (Mar 22, 2011)

backstay said:


> 705 is not bad, I use option C for sizing, add up all the breakers except the main and stay under its rating.


this.....?



> *705.12 Point of Connection.*(c) The sum of the ampere ratings of all overcurrent devices on panelboards, both load and supply devices, excluding the rating of the overcurrent device protecting the
> busbar, shall not exceed the ampacity of the busbar.


I don't understand this at all....

making into a 100A 30 cir can might be 30X20A=600A

are 100A panel busbars rated for 600A?:blink:

to further this, i'm told (local guru's) that i may need to upgrade 100A services to a 200A panel , but i can maintain the same service entrance conductors.....:001_huh:

corn fusing.....~CS~


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## backstay (Feb 3, 2011)

chicken steve said:


> this.....?
> 
> 
> 
> ...


I don't run these into 30 space panels. Last one was a 70 amp MLO four space with two 30 amp DPs. The inverter output times 125% was 62.5 amps. Then into an eight space 200 amp with only the solar going to it. That panel then is fed by a 400 amp service. I've been at this for along time, oldest system is over twenty years. I've never seen a buss failure. Maybe I'm just lucky, but my systems put out maximum output because of the cold temps.

Generators in a cogen system have the same issues.


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## chicken steve (Mar 22, 2011)

Backstay, we've been running 30A DP's into 100A house panels here. 

So what do i look for? Do i wait until it's sunny,crank up the house & amp probe it?

Is there some _'rule of thumb'_ ......?

~CS~


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## backstay (Feb 3, 2011)

chicken steve said:


> Backstay, we've been running 30A DP's into 100A house panels here.
> 
> So what do i look for? Do i wait until it's sunny,crank up the house & amp probe it?
> 
> ...


Why these 100 amp backfeed breakers are failing on 40 amp PV systems is unclear to me. The whole buss rating has more to do with faults and available current from two sources. The breakers should be cycled a few times a year and probably replaced at some interval. As far as 30 DPs go, it's back to what's in the panel now. Either do the calc in A or B, or the way in C. But what happens after you leave? Circuits get added. I have MH's book on this.

http://www.amazon.com/gp/aw/d/19326...-11&pi=AC_SX110_SY165_QL70&keywords=mike+holt


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## backstay (Feb 3, 2011)

Here is a graphic of A, where the backfeed breaker is not at the opposit end of the buss. So you buy a convertible panel and install a main that is smaller than the buss rating. Feeding the panel with a fused disconnect would also work I'd think.


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## backstay (Feb 3, 2011)

Here is b, backfeed breaker at opposit end from utility. Get MH book, worth the money.


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## backstay (Feb 3, 2011)

And C, you need a label for this one and for B.


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## shortcircuit2 (Jan 4, 2015)

macmikeman said:


> The following three pictures are from the 40 panel system tied to a single 100 amp (shared with a panel) main breaker that I spoke about. You judge for yourselves if it is a good idea to put 40x 240 rated panels onto a 1/0 feeder for a panel protected by a 100 amp breaker plugged onto a 200 amp rated bus.
> 
> 
> 
> ...


Is this service equipment without a main breaker? Is it a meter on one side and main lug panel on the side that had the meltdown?

Looks to me like the breaker may have been loosely stabbed in...i mean like the jaws where loose at the contact point with the bussing...


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## Meadow (Jan 14, 2011)

macmikeman said:


> The following three pictures are from the 40 panel system tied to a single 100 amp (shared with a panel) main breaker that I spoke about. You judge for yourselves if it is a good idea to put 40x 240 rated panels onto a 1/0 feeder for a panel protected by a 100 amp breaker plugged onto a 200 amp rated bus.
> 
> 
> 
> ...



Looks like a loose breaker to stab connection. Ive seen this happen with 15 amp circuits.


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## Meadow (Jan 14, 2011)

macmikeman said:


> Not me, I wired that house for my wife's cousin. He asked me to do a pv but I wasn't interested at that time, so he brought in one of the big 5 locally. My meter/main has 4 spaces so you can run two ser cables from it to individual sub panels and put 2 100 amp disconnect breakers in the customer side of the can. The solar company tagged onto one of those 100 amp protected subfeeders just below the 100 amp breaker. I asked the poco trouble call lineman today as to how often he is seeing this stuff happen these days and he replied that it is daily now. I told him about the forty panels and he just shook his head.



Im confused. This has to be a defect in the panels. I cant picture this happening when done to code.


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## chicken steve (Mar 22, 2011)

So am I AT....

One would think if useage in a system was less , less heating would occur

Not so....and it beckons the _theory_ of it all :blink:

I'm trying to visualize the flow of electrons in AC, they really don't flow as much as bump and charge each other back and forth right?:001_huh:

So we have all these electrons doing the bump , from two sources , right?

Now i sound like **** Clark narrating American Bandstand.....~CS~:no:


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## backstay (Feb 3, 2011)

chicken steve said:


> So am I AT....
> 
> One would think if useage in a system was less , less heating would occur
> 
> ...


Think of it as parallel feeds. On a normal 200 amp service you can push through that breaker a certain amount of energy. Now you add a second source and the energy the buss could see is more than its designed for. Also the output of the solar could be high for 6 or more hours. Than may be what's happening in Hawaii.


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## Switched (Dec 23, 2012)

This is good stuff guys!


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## Meadow (Jan 14, 2011)

chicken steve said:


> So am I AT....
> 
> One would think if useage in a system was less , less heating would occur
> 
> ...


As long as any part of the buss bar does not exceed its rating nothing will happen.

The issue with solar is its like having 2 paralleled services to a panel. This creates an issue in that the main breaker does not "see" all the load being drawn out of a panel. A 100amp panel could have 130 amps of load drawn out of it, 90 across the main and 40 from the solar module.


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## Meadow (Jan 14, 2011)

backstay said:


> Think of it as parallel feeds. On a normal 200 amp service you can push through that breaker a certain amount of energy. Now you add a second source and the energy the buss could see is more than its designed for. Also the output of the solar could be high for 6 or more hours. Than may be what's happening in Hawaii.



I can understand that, but why would it cause a stab to burn up? :blink:


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## backstay (Feb 3, 2011)

AcidTrip said:


> I can understand that, but why would it cause a stab to burn up? :blink:


More a problem of the breaker to buss connection if you ask me. Not the buss failing. But what do I know, I've never had one fail. And the failure should not be at the solar breaker connection. That spot only see the inverter output. It would be at the other sub feed breaker. In my systems, that's a lug not a breaker. Either the panel has feed through lugs or it's a MLO that I only have back feed breakers in.


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## chicken steve (Mar 22, 2011)

Well you probably build your stuff_ apocalyptic proof_ BackStay, as you've been at it long enough to be aware of the sore spots ....

~CS~


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## chicken steve (Mar 22, 2011)

AcidTrip said:


> I can understand that, but why would it cause a stab to burn up? :blink:



Weak link in the chain?:blink:

What about all these solar fields feeding back on older infrastructure?

Are the Xformers upsized? 

I've obviously more Q's than A's need to get MH's book...

~CS~


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## Meadow (Jan 14, 2011)

chicken steve said:


> Weak link in the chain?:blink:
> 
> What about all these solar fields feeding back on older infrastructure?
> 
> ...



My theory is that it was simply a defective stab rather then solar feeding by itself. 

Let me look at the Mike Holt book again, but when I glanced at it its based on current at any one point in a node not exceeding the rated current of the buss bar Assembly. I know of buss duct systems that spit out more then the rating off the ducts themselves...


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## chicken steve (Mar 22, 2011)

Well i tend to believe Mac when he's _not_ talkin' politics AT :laughing:

And there's more than one local solar guru insisting on a _panel_ upgrade for their installs on my turf

Panel, not _entire service_ upgrade.....

Don't mean to be a _peckerhead_ about it, and correct me if i'm wrong, but all current circulates _back_ to the serving Xformer, right?:blink:

So enter the solar fields , we've got more popping up here than we so silage corn these days, lotta it has to do with a Gov so _green_ he could lead the St Paddy's day parade ....:no::whistling2:

And we're still dealing with FDR era electrical infrastructure _installed_ via the rural electrification program years .....:001_huh:

~CS~


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## Meadow (Jan 14, 2011)

chicken steve said:


> Well i tend to believe Mac when he's _not_ talkin' politics AT :laughing:
> 
> And there's more than one local solar guru insisting on a _panel_ upgrade for their installs on my turf
> 
> Panel, not _entire service_ upgrade.....


What are they saying regarding the panels? Perhaps its not current as much as continuous loading. I know places with high, constant loading enjoy bolt on breakers. 




> Don't mean to be a _peckerhead_ about it, and correct me if i'm wrong, but all current circulates _back_ to the serving Xformer, right?:blink:



It depends. Sometimes yes, that is if no load is being drawn. Usually its consumed by the load, and what is left over goes out the meter. 



> So enter the solar fields , we've got more popping up here than we so silage corn these days, lotta it has to do with a Gov so _green_ he could lead the St Paddy's day parade ....:no::whistling2:
> 
> And we're still dealing with FDR era electrical infrastructure _installed_ via the rural electrification program years .....:001_huh:
> 
> ~CS~


I can see POCOs having the most issues. Old protective relaying and new solar dont mix well.


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