Best Solar Panel Manufacturers

[electrofelon]

Reducing the neutral can be done on any inverter that only uses the neutral as a voltage reference. Sometimes it's in the installation manual but sometimes you need to ask the manufacturer.

Yeah, but some manufacturers don't state that and wont tell you either, like it's a matter of national security or some unsolved mystery :slaphead:

Then there is the option that chint and solectria state that the neutral can be jumpered to the egc terminal and the neutral conductor eliminated all together - potentially not liked by inspectors tho.

 

[ggunn]

Yeah, but some manufacturers don't state that and wont tell you either, like it's a matter of national security or some unsolved mystery :slaphead:

Then there is the option that chint and solectria state that the neutral can be jumpered to the egc terminal and the neutral conductor eliminated all together - potentially not liked by inspectors tho.

If they won't give it to you in writing, then, yes, you'll have to use a full sized neutral. It's not a secret, necessarily; they might see it as a potential liability. Also, I have seen three phase inverters that under the hood were three separate single phase inverters phase to neutral.

 

[electrofelon]

If they won't give it to you in writing, then, yes, you'll have to use a full sized neutral. It's not a secret, necessarily; they might see it as a potential liability. Also, I have seen three phase inverters that under the hood were three separate single phase inverters phase to neutral.

Being someone who has installed pv systems in georgia in august with fire ants everywhere, and upstate NY in the mud and the snow, IMO there is no reason we should be installing neutral conductors to inverters :rant:

 

[ggunn]

Being someone who has installed pv systems in georgia in august with fire ants everywhere, and upstate NY in the mud and the snow, IMO there is no reason we should be installing neutral conductors to inverters :rant:

I can't fight that logic. I can't fight what I can't see.

 

[GoldDigger]

Being someone who has installed pv systems in georgia in august with fire ants everywhere, and upstate NY in the mud and the snow, IMO there is no reason we should be installing neutral conductors to inverters :rant:

All logic and reason aside, if the manufacturer's instructions (listing conditions) for the inverter require it the code enforces that requirement.

And many 240V inverters have a test for voltage balance between L1-N and L2-N (required or encouraged by UL?). You would have to fake that with a voltage divider of some sort or hope that local ground will fill the need.

 

[jaggedben]

Many inverters default to looking for the neutral but can be set to operate without it. In that case the neutral can simply be eliminated. Enphase got rid of the neutral entirely on their new products; you still need one for the Envoy if you use the combiner, but you can invoke the calculated load on the feeder to size it per the EGC, no 705 rule need be invoked.

 

[electrofelon]

Not disagreeing with anything here, but my point is if everyone - installers, inverter manufacturers, UL, inspectors, etc - would just get on the same page we could get rid of the neuter and save everyone time and money. The last large system I worked on had 67 inverters and 6 combiner panelboards. How much did that neutral that was a completely "unnecessary" cost?

 

[Ozymandias]

One suggestion is to work with a trusted distributor. The experienced distributors tend to narrow down their module offerings to a few manufacturers and models that they have researched, to the best of their ability, and judged to be best values.

For some who use sunpower modules, does a company have to be a sunpower installer to purchase their modules and racking? I've read comparisons and at 96 cells and 41 pounds, sunpower is impressive. I assume they are much larger as well. I live in the midwest so my distributor choices are narrow and freight is a nonstarter unless I want to purchase large quantities and sit on them till I can install them. Don't think I could do that fast enough.

 

[Ravenvalor]

Thanks for the tip about taking a look at solar world LG and hyundai. they all look pretty good .should i use all three of them as needed for job requirements? Are there any other companies that are rock solid and make a great panel? Id rather stay clear of chinese but if they are controlling the market then i will have to get into the ring with them.
thanks for the help with this large amount of data!!!!

best regards

 

[ggunn]

Thanks for the tip about taking a look at solar world LG and hyundai... Are there any other companies that are rock solid and make a great panel?

Yes, there are.

 

[pv_n00b]

I found the link to that thread on reducing or eliminating the neutral conductor:

http://forums.mikeholt.com/showthread.php?t=188721

I posted a comment on that thread that still works. To add a little, UL 1741 listed inverters have to measure phase to neutral voltage if the service is grounded to detect a phase to neutral voltage problem with the service and shut down. No way to get around that if the inverter is going to be listed. Some inverters actually need the full neutral as a current carrying conductor and some just use it for making the phase to neutral voltage measurement. A few inverter manufacturers have done what I consider is a questionable end run at this if they only use the neutral for voltage measurement by measuring the phase to EGC voltage at the inverter, not using a neutral, and assuming that it is the same as the phase to neutral voltage at the service. If the service is properly grounded, the EGC is in good condition, and there is no current on the EGC then this is true, but it's not as assured as if a dedicated neutral were used. It's more of a safety issue than an operational issue but if the EGC is used and there is a voltage on it due to some other problem in the system it could cause the inverter to intermittently shut down.

 

[electrofelon]

I posted a comment on that thread that still works. To add a little, UL 1741 listed inverters have to measure phase to neutral voltage if the service is grounded to detect a phase to neutral voltage problem with the service and shut down. No way to get around that if the inverter is going to be listed. Some inverters actually need the full neutral as a current carrying conductor and some just use it for making the phase to neutral voltage measurement. A few inverter manufacturers have done [bold]what I consider is a questionable end run at this if they only use the neutral for voltage measurement by measuring the phase to EGC voltage at the inverter, not using a neutral, and assuming that it is the same as the phase to neutral voltage at the service. If the service is properly grounded, the EGC is in good condition, and there is no current on the EGC then this is true, but it's not as assured as if a dedicated neutral were used. [/bold]It's more of a safety issue than an operational issue but if the EGC is used and there is a voltage on it due to some other problem in the system it could cause the inverter to intermittently shut down.

anything you say about the EGC could happen to the neutral. In fact the neutral is more likely to have current on it and thus not be as "good" a voltage reference. I see absolutely no issue using the EGC to measure the voltage.

 

[ggunn]

I posted a comment on that thread that still works. To add a little, UL 1741 listed inverters have to measure phase to neutral voltage if the service is grounded to detect a phase to neutral voltage problem with the service and shut down. No way to get around that if the inverter is going to be listed. Some inverters actually need the full neutral as a current carrying conductor and some just use it for making the phase to neutral voltage measurement. A few inverter manufacturers have done what I consider is a questionable end run at this if they only use the neutral for voltage measurement by measuring the phase to EGC voltage at the inverter, not using a neutral, and assuming that it is the same as the phase to neutral voltage at the service. If the service is properly grounded, the EGC is in good condition, and there is no current on the EGC then this is true, but it's not as assured as if a dedicated neutral were used. It's more of a safety issue than an operational issue but if the EGC is used and there is a voltage on it due to some other problem in the system it could cause the inverter to intermittently shut down.

I know of several inverters that do not require a neutral of any size.

 

[jaggedben]

I posted a comment on that thread that still works. To add a little, UL 1741 listed inverters have to measure phase to neutral voltage if the service is grounded to detect a phase to neutral voltage problem with the service and shut down. No way to get around that if the inverter is going to be listed. A few inverter manufacturers have done what I consider is a questionable end run at this if they only use the neutral for voltage measurement by measuring the phase to EGC voltage at the inverter, not using a neutral, and assuming that it is the same as the phase to neutral voltage at the service. If the service is properly grounded, the EGC is in good condition, and there is no current on the EGC then this is true, but it's not as assured as if a dedicated neutral were used. It's more of a safety issue than an operational issue but if the EGC is used and there is a voltage on it due to some other problem in the system it could cause the inverter to intermittently shut down.

I know of several inverters that do not require a neutral of any size.

I can ditto ggunn, and I don't understand how the UL requirement can be exactly such unless something improper is happening in the listing process. Also, what exactly is the safety issue if inverters don't shut down in a phase imbalance?

 

[pv_n00b]

anything you say about the EGC could happen to the neutral. In fact the neutral is more likely to have current on it and thus not be as "good" a voltage reference. I see absolutely no issue using the EGC to measure the voltage.

There are some limited cases in the NEC where the EGC is allowed to act as a current carrying conductor. One I ran across recently is electronic controls for lighting where no neutral was brought to the switch. But overall the NEC does not allow it, neutrals are designed to carry current and EGCs are not. If the code stated that the EGC could be used by inverters to do the phase voltage test then it would not be an issue but it does not. Does it work? It seems to based on prior usage. Is it allowed? No.

I know of several inverters that do not require a neutral of any size.

Neutrals are not required in delta services, several inverters can be used with delta services, therefore several inverters have the option of not using the neutral with delta services. I'd be glad to see a manufacturer and model listed with an install manual that says to connect it up to a grounded 4 wire service without any neutral. Please let me know which ones you know of.

I can ditto ggunn, and I don't understand how the UL requirement can be exactly such unless something improper is happening in the listing process. Also, what exactly is the safety issue if inverters don't shut down in a phase imbalance?

Just telling you what I know, you can take it up with UL if you don't agree with it. Get on the STP and tell them how wrong they are. And since UL 1741 is based on IEEE 1547 you should probably get involved there too. The requirement for phase voltage monitoring comes from that IEEE standard, and I would be willing to bet from the utility members on the standard panel. It's all interrelated.

 

[ggunn]

Neutrals are not required in delta services, several inverters can be used with delta services, therefore several inverters have the option of not using the neutral with delta services. I'd be glad to see a manufacturer and model listed with an install manual that says to connect it up to a grounded 4 wire service without any neutral. Please let me know which ones you know of.

I'm not sure what you are asking, but the SMA 30kW Tripower can be connected 480/277V wye (with neutral) or 480V delta (no neutral). In the latter case I don't think it cares whether the CCC's are ground referenced or not.

 

[jaggedben]

Neutrals are not required in delta services, several inverters can be used with delta services, therefore several inverters have the option of not using the neutral with delta services. I'd be glad to see a manufacturer and model listed with an install manual that says to connect it up to a grounded 4 wire service without any neutral. Please let me know which ones you know of.

Enphase IQ series. To either a 208 Wye or a 240 high-leg delta.

I thought there were a couple Fronius models, too, although apparently the current models have a different setting for delta and high-leg delta.
Some Satcons back in the day, as well.

 

[ggunn]

Enphase IQ series. To either a 208 Wye or a 240 high-leg delta.

I thought there were a couple Fronius models, too, although apparently the current models have a different setting for delta and high-leg delta.
Some Satcons back in the day, as well.

Also SunPower micros, 240V split phase only. Ground connection but no neutral.

 

[pv_n00b]

Enphase IQ series. To either a 208 Wye or a 240 high-leg delta.

I thought there were a couple Fronius models, too, although apparently the current models have a different setting for delta and high-leg delta.
Some Satcons back in the day, as well.

The old Satcons used the EGC to do the phase voltage measurement. Somehow they got their NRTL to buy off on that in their listing. That's stopped now.
The Enphase 3 phase system is actually made up of single phase inverters and 3 phase is created by how they are interconnected in the harness. Single phase inverters connected L-L do not require a neutral, tricky 'eh?

I'm not sure what you are asking, but the SMA 30kW Tripower can be connected 480/277V wye (with neutral) or 480V delta (no neutral). In the latter case I don't think it cares whether the CCC's are ground referenced or not.

You are correct, grounding does not matter on the delta and with no phase voltage to measure there is no neutral.

Also SunPower micros, 240V split phase only. Ground connection but no neutral.

Single phase 240V inverters connected L-L don't need a phase voltage reference so no neutral required.

 

[electrofelon]

There are some limited cases in the NEC where the EGC is allowed to act as a current carrying conductor. One I ran across recently is electronic controls for lighting where no neutral was brought to the switch. But overall the NEC does not allow it, neutrals are designed to carry current and EGCs are not. If the code stated that the EGC could be used by inverters to do the phase voltage test then it would not be an issue but it does not. Does it work? It seems to based on prior usage. Is it allowed? No.

I wouldn't consider a neutral used only for voltage measurement with a high impedance meter to be current carrying. The NEC doesnt say its ok, but they dont say its not OK either.


I still stand by my belief that there is no functional requirement (other than NEC, UL, IEEE, etc "red tape") for the neutral conductor (except if the neutral is actually current carrying as has been mentioned, which in that case it shouldnt be designed that way IMO). As I said before, it just seems like something we could get rid of if everyone would get on the same page.