Can someone point me in the right direction regarding the code compliance and manufacture requirements for MC4's and Amphenol connectors? I've heard that connectors are only listed to mate with ones made by the same company. I've heard that as long as they're UL listed then it doesn't matter who made them. Are optimizers and micro inverters all universally interchangeable? Any info from UL or code sections would be appreciated.
MC4 Requirements
- Thread starter sketchy
- Start date
NEC 690.33(C) requires that: "Where mating connectors are not of the identical type and brand, they shall be listed and identified for intermatability, as described in the manufacturer’s instructions."
While it is possible for connectors from different manufacturers to the listed for intermatability as far as I know none are. Everyone wants to be listed to mate with MC4s and Stäubli won't do it.
While it is possible for connectors from different manufacturers to the listed for intermatability as far as I know none are. Everyone wants to be listed to mate with MC4s and Stäubli won't do it.
Carultch
Senior Member
- Location
- Massachusetts
No, they are fundamentally different devices.
What they have in common:
1. They are both module-level devices installed in the array adjacent to or on each module
2. They are both methods of achieving the requirements of rapid shutdown (NEC2017 and later).
3. They both localize the power processing to the module-level, so that a shaded module doesn't hinder the performance of fully exposed modules.
What the essential differences are:
1. Microinverters do the complete power conditioning at the same device, and produce AC power to match the building's grid. Outputs are combined in parallel with other microinverters of the same branch circuit, using a brand-specific cable system to combine them in parallel.
2. Optimizers still output DC, but they modify the voltage and current of each one. Therefore, an inverter is required to convert the output to match the building's grid voltage. This allows them to all match the same output current (independently of the module's output current) so they can be combined in series. Each will contribute an output voltage that's proportional to available power, and they all add up to the inverter's target input voltage.
3. Optimizers are meant to be used as part of a brand-specific combination with an inverter of the same brand, and neither is meant to work without the other, as is the case for SolarEdge. Tigo by contrast, had an optimizer solution that would work with standard inverters, in what would otherwise be a conventional string of "wild PV".
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
No, they are not. This is why micro and optimizer manufacturers make different models with different connectors from time to time.
So when Enphase says in their data sheets that they have MC4 connectors it doesn't matter because they haven't been listed for intermatability with MC4's. And there are no connectors that are listed as such. That means every micro installed does not meet code because there are no products made that do meet code. How is this possible? Do people make whips with different manufacturer connectors on each end?
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
No, when Enphase says they have MC4s it ought to mean they're genuine listed MC4s. Most likely they're paying Stäubli something to license the factory to produce them, or maybe actually buying them from Stäubli for the factory to assemble onto the micros.
I seem to recall there has been a history of marketing Amphenol as compatible with MC4 but that was like 10 years ago. It was a bit of a s---show at one point. But as pv_noob said that is not really accepted and I don't think manufacturers are still trying to pinch pennies that way.
I seem to recall there has been a history of marketing Amphenol as compatible with MC4 but that was like 10 years ago. It was a bit of a s---show at one point. But as pv_noob said that is not really accepted and I don't think manufacturers are still trying to pinch pennies that way.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
On a number of the IQ series of Enphase micros the DC connectors are a separate part that can be switched out for the connector that is compatible with your module.
What you have to watch out for is a manufacturer that says they use "MC4 compatible" connectors on their devices. That means they are not using an actual MC4 connector. There are no UL Listed MC4 compatible connectors from different manufacturers because UL requires both connector manufacturers to submit together for the listing and the market leaders have nothing to gain from this.
Also, people rarely specify, or even ask, what connectors are on the equipment when they order it. They just assume that whatever they get will click together. The "If it clicks, it fits" mentality is strong.
Birken Vogt
Senior Member
- Location
- Grass Valley, Ca
As it should be. The MC4 "style" connector had the potential to be a good solution.
How they managed to screw it up into the intermating-but-not-really-compatible mess we have today, I can't understand.
The way I'm understanding it is that Staubli will not support any 3rd party's documentation stating "MC4 Compatible". When Enphase says that their DC connector type is MC4 you can take that to the bank because the connectors are stamped "MC". BUT if the PV module's connectors don't have "MC" stamped on them that's a problem. I checked a few different manufacturer's and they do have the stamp. There must be a lot of panel manufacturers that don't.
There was never an industry standard for a connector everyone could build to. To make MC4 compatible connectors a manufacturer had to reverse engineering the MC4 connector and make a connector that would mate to it. Some did a better job than others, which is why mis-mated connectors can overheat. Some manufacturers went a step farther and had a lab test their connector with an MC4 and issue a letter saying they are fine together. Manufacturer's would email that out if questioned. But it's not the same as UL Listed and that is what the NEC requires.
If it clicks, if fits is the absolute lowest bar for intermatability.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
I checked datasheets for some of the tier 1 modules we sell (Silfab, Q-Cells, REC, ...) and they all actually say 'Stäubli MC4'. (One didn't have the umlaut, lol). If your older or no-name modules say something different, then yes, technically that could be a code violation without an adapter or something. I've used adapters in the past.
Like I said, 10 years ago there was less consensus on all this; and people would say Amphenol was compatible with MC4, or whatever, as pv_noob alluded to. But nowadays I don't think manufacturers make that claim. MC4 is pretty much the defacto standard and almost everyone is paying royalties to Stäubli because why would Stäubli ever say they don't care about their IP. Without a very different government and code making structure, it is what it is.
Like I said, 10 years ago there was less consensus on all this; and people would say Amphenol was compatible with MC4, or whatever, as pv_noob alluded to. But nowadays I don't think manufacturers make that claim. MC4 is pretty much the defacto standard and almost everyone is paying royalties to Stäubli because why would Stäubli ever say they don't care about their IP. Without a very different government and code making structure, it is what it is.