# Generator install w/solar panels



## Meadow (Jan 14, 2011)

I see no problem, however contact the manufacturer of the solar inverter just in case there is some unknown incompatibility issue.


----------



## ElectricJoeNJ (Feb 24, 2011)

meadow said:


> I see no problem, however contact the manufacturer of the solar inverter just in case there is some unknown incompatibility issue.


How do you see no problem with this. Think about it like this. When solar power is backfed into the grid it is consumed by other houses. If you have a power outage and use your generator to feed your house and in turn have your solar system turn on, where is the excess power going to go? It is going to back feed the generator. Something tells me that they are not designed to handle a backfeed like that.


----------



## cabletie (Feb 12, 2011)

The inverter is not going to come on. No generator is going to fool an inverter into thinking utility power has been restored. I also agree with talking to the inverter manufacture about your concerns, but having both on at the same time is not going to happen from what I have been told.


----------



## ElectricJoeNJ (Feb 24, 2011)

cabletie said:


> The inverter is not going to come on. No generator is going to fool an inverter into thinking utility power has been restored. I also agree with talking to the inverter manufacture about your concerns, but having both on at the same time is not going to happen from what I have been told.


I'm sorry, but thats the stupidest thing I've ever heard. All all solar inverter needs to operate is 240 volts @ 60 hertz. As long as your generator puts that out it will turn on. Back to the OP. I DONT recommend using a generator to turn on an inverter.


----------



## McClary’s Electrical (Feb 21, 2009)

meadow said:


> I see no problem, however contact the manufacturer of the solar inverter just in case there is some unknown incompatibility issue.


 
You must have bumped your head before posting this...


cabletie said:


> The inverter is not going to come on. No generator is going to fool an inverter into thinking utility power has been restored. I also agree with talking to the inverter manufacture about your concerns, but having both on at the same time is not going to happen from what I have been told.


 And you too...



ElectricJoeNJ said:


> I'm sorry, but thats the stupidest thing I've ever heard. All all solar inverter needs to operate is 240 volts @ 60 hertz. As long as your generator puts that out it will turn on. Back to the OP. I DONT recommend using a generator to turn on an inverter.


 
I agree 100% . Not only is the solar gonna try and run, but once it does, the inverter is gonna go crazy trying to sync with a POS generator. We need to know what type of inverter, because some of safety interlocks but I would probably wire this system through a contactor, that is energized by grid power, before the backfeed interconnection point, so it will be disabled during generator runs. I would never, ever, let a grid tied solar syatem try and sync to a generator.


----------



## backstay (Feb 3, 2011)

....


----------



## cabletie (Feb 12, 2011)

ElectricJoeNJ said:


> I'm sorry, but thats the stupidest thing I've ever heard. All all solar inverter needs to operate is 240 volts @ 60 hertz. As long as your generator puts that out it will turn on. Back to the OP. I DONT recommend using a generator to turn on an inverter.


 I was told in two different solar classes that I have taken, that an inverter will know the difference between the utility power and the generator power, and would not turn on. Solar pro magazine has a good article "Interaction of grid-direct inverters with backup generators". There are a few scenarios none at all harmful. With a good quality generator it will try to synchronize as long as it is within UL 1741 limits. 
 Here is the authors quote "But what if the instantaneous power output for the PV system is larger than the building loads? If there is more power available from the PV system than the total load can consume, the inverter will attempt to put the extra power somewhere, raising the ac line voltage, for example. In this case, when the PV system comes on line, as soon as the voltage or frequency reaches the maximum UL 1741 limit, the inverter will trip off. Unless the total load demand exceeds the instantaneous power output of the PV system at all times, the grid-tied PV system has no chance of staying connected to the generator output".




> I DONT recommend using a generator to turn on an inverter


Neither do I, that would be stupid, but for safty concerns I dont think anything is going to happen. It is not the best set up but Please show me somewhere in the code where this setup would be a violation.

Backstay, I am curious does it actualy sync. or is the solar inverter off and running on batteries when the generator is on?



> Sparksaplenty "One of my customers wants a manual-transfer gen-set connection. No problem there. I plan to use a Interlock-kit unit to feed his entire panel."


Just tell him to shut off the solar breaker when he turns on the generator breaker or label it that way, if they forget oh well no harm.


----------



## backstay (Feb 3, 2011)

....


----------



## janagyjr (Feb 7, 2011)

I'm curious, though it's probably OT, but isn't it kind of backwards to have the solar trip off when utility does? Isn't that when you would want the panels to be doing something other than plugging into the grid or charging its batteries? Did I miss something basic here? I've not covered solar anything so my ignorance is pretty complete.


----------



## backstay (Feb 3, 2011)

....


----------



## smithbell81 (Oct 25, 2011)

Hello, there. I just bought a solar panel from this company they gave me this manual for analyzing or how to operate it. Last weekend I paint the lens from inside so it can consume more light as not before. But now the heating is going down as I didn’t expected and I also think that there is broken fire line has occurred in my solar lens. Please help me to solve out my problem.


----------



## wpelectric94 (9 mo ago)

Sparksaplenty said:


> With all of the power outages last week due to hurricane Irene, I have been besieged with generator install jobs.
> One of my customers wants a manual-transfer gen-set connection. No problem there. I plan to use a Interlock-kit unit to feed his entire panel.
> Manual Transfer Switch | Extension Cord | Generator Interlock Kit
> But he has a utility-intertied solar array. You know, the type that dis-connects itself during a power outage. These are generally connected by back-feeding a branch circuit 2-pole breaker, but I have seen others that are bugged-on to the main ahead of the main breaker, with their own disconnect
> ...


Just install a rib relay and tap off the load side of the breaker with the tap rule when generator comes on the normally close contacts open when rib relay is energized then you have no issues it becomes electrically interlocked


----------



## backstay (Feb 3, 2011)

wpelectric94 said:


> Just install a rib relay and tap off the load side of the breaker with the tap rule when generator comes on the normally close contacts open when rib relay is energized then you have no issues it becomes electrically interlocked


That was 2011.


----------



## emtnut (Mar 1, 2015)

backstay said:


> ...


FIFY, just to keep your theme for this thread going


----------



## Almost Retired (Sep 14, 2021)

@backstay 
2018 i installed some grid tied inverters for solar, they did not allow running the solar with the generator
but i dont know what they did when they added batteries or even whether that could be grid tied.

but my question is : what are they doing now ?

can you have batteries and a generator on grid tied solar ?


----------



## nrp3 (Jan 24, 2009)

I've run into the back fed breaker on a couple of installs of late and have had the solar folks come and move the grid tie to ahead of the ATS so the inverter and generator aren't coming together. Not taking any chances. Cost of letting the blue smoke out...


----------



## backstay (Feb 3, 2011)

Almost Retired said:


> @backstay
> 2018 i installed some grid tied inverters for solar, they did not allow running the solar with the generator
> but i dont know what they did when they added batteries or even whether that could be grid tied.
> 
> ...


Two solutions, generator sub panel where the backed up loads go. This would be for a grid tie, no batteries system. With a battery backup, the inverters have a generator input built into them. The inverter controls the flow of power and when the generator is run. There is no ATS.


----------



## Almost Retired (Sep 14, 2021)

backstay said:


> Two solutions, generator sub panel where the backed up loads go. This would be for a grid tie, no batteries system. With a battery backup, the inverters have a generator input built into them. The inverter controls the flow of power and when the generator is run. There is no ATS.


so batteries are still not grid tie ?


----------



## nrp3 (Jan 24, 2009)

I don't think that is the case. I think it depends upon the system being built. I'm guessing a vast majority of those Powerwalls are grid tied solar.


----------



## backstay (Feb 3, 2011)

Almost Retired said:


> so batteries are still not grid tie ?


Yes they are grid tied. The inverter decides if you are selling, buying, or generating. Here is an Outback system I installed. This is a screenshot.


----------



## Almost Retired (Sep 14, 2021)

edit


----------



## Almost Retired (Sep 14, 2021)

backstay said:


> Yes they are grid tied. The inverter decides if you are selling, buying, or generating. Here is an Outback system I installed. This is a screenshot.
> View attachment 164962



OK. i thought i had seen that some time back


----------



## Almost Retired (Sep 14, 2021)

nrp3 said:


> I don't think that is the case. I think it depends upon the system being built. I'm guessing a vast majority of those Powerwalls are grid tied solar.


a guess is similar to an assumption


----------



## backstay (Feb 3, 2011)

The power wall has an inverter inside.


----------



## backstay (Feb 3, 2011)

backstay said:


> Two solutions, generator sub panel where the backed up loads go. This would be for a grid tie, no batteries system. With a battery backup, the inverters have a generator input built into them. The inverter controls the flow of power and when the generator is run. There is no ATS.


I should say there is a third solution. That is to bring the grid tie in before the service disconnect. This is like having two services. Your solar just goes through a breaker to the line side of your service breaker. Power then goes to your loads or to the grid, or both depending on your system size and load.


----------



## wpelectric94 (9 mo ago)

nrp3 said:


> I've run into the back fed breaker on a couple of installs of late and have had the solar folks come and move the grid tie to ahead of the ATS so the inverter and generator aren't coming together. Not taking any chances. Cost of letting the blue smoke out...


That's actually the right way to do it but sometimes the solar guys don't want to come out and then you're responsible if you end up moving it


----------

