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Old 06-24-2023, 12:55 PM   #1
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Major Safety Concerns in 97% of Rooftop PV Systems

Clean Energy Associates (CEA) performed a safety audit on more than 600 rooftop PV systems in, 14 countries, and it's finding show that 97% of installations have major safety concerns. The report states that 49% of sites have grounding issues, 47% have damaged modules, and 41% have cross-mated connectors.

*CEA performed inspections in the United States, United Kingdom, Italy, Spain, India, Japan, United Arab Emirates, Australia, Canada, Mexico, Czech Republic, Germany, Poland, and France.



Grounding issues and damaged modules are the most common safety problems among rooftop solar projects, according to Clean Energy Associates (CEA). Almost half (49%) of the audited projects had grounding issues. These typically took place at the inverter or equipment pad, between PV array blocks and module rows where short conduit runs were necessary, and on extended conduits runs, where additional grounding straps are required.

The grounding issues discovered included incorrect designs, moisture or water intrusion, installation instructions not followed by installers, poor quality assurance inspections & overlooked installation errors.

The second culprit, showing in 47% of installations, included damage to modules. Possibly caused by incorrect installation or cleaning methods, including walking on modules, as well as extreme weather events.

Next up, 41% of installations have cross-mated connectors, often resulting from a misunderstanding of UL-listed connector pairings and the use of field-made connectors, which do not match the module connector.

Additional findings of the audit show that 40% have poor terminations and improperly assembled connectors, 31% have module hotspots, 27% have cables across sharp edges, 26% have broken or damaged connectors (as well as water ingress) and 19% have enclosure hotpots.

Simon Yuen wrote an article about the report, published in PV-Tech:
www.pv-tech.org/grounding-issues-and-damaged-modules-among-most-common-rooftop-solar-safety-problems-cea

Download the CEA Report here:
www.cea3.com/cea-blog/tag/Safety+Audits

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Old 06-25-2023, 11:05 AM   #2
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Regarding grounding, I would be interested to read a survey of how RV and mobile PV systems fare, especially considering their necessarily different grounding protocols.

John
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Old 06-26-2023, 10:06 AM   #3
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I didn't understand what they meant by cross-mated connectors. Figured the MC4s were pretty much dummy-proof. This article explains the problem. My guess is the number of Skoolie / RV installs with this potential problem is FAR greater than 41%.

the solarblogger: Cross-mating of Solar DC Connectors and Fire Safety
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Old 06-26-2023, 10:31 AM   #4
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And weirdly, no mention of unsafe physical mounting?
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Old 06-26-2023, 06:45 PM   #5
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Originally Posted by TheHubbardBus View Post
I didn't understand what they meant by cross-mated connectors. Figured the MC4s were pretty much dummy-proof. This article explains the problem. My guess is the number of Skoolie / RV installs with this potential problem is FAR greater than 41%.

the solarblogger: Cross-mating of Solar DC Connectors and Fire Safety

Good article, had no idea the mc-4 connectors were not all the same. I have bought all my connectors from the same company so have not had any trouble, but good to know they are not all interchangable
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Old 06-26-2023, 11:52 PM   #6
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I didn't understand what they meant by cross-mated connectors. Figured the MC4s were pretty much dummy-proof. This article explains the problem. My guess is the number of Skoolie / RV installs with this potential problem is FAR greater than 41%.

the solarblogger: Cross-mating of Solar DC Connectors and Fire Safety

What they mean is that the portion of the connector intended to be the HOT side and the portion intended to be the COLD side were put on the cables backwards. It mentioned field installed connectors and that's likely the cause in all such cross connections.

In other words, the two sides are not identical and the side intended to be on the end of the wire coming FROM the PV panel was instead the one intended to be the one that connects to that one.


Hopefully that makes more sense now.
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Old 06-27-2023, 01:05 AM   #7
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PV Connector Mating and Intermatability

Lol 🤣 Unfortunately, no

The solar industry’s most dangerous misconception might be the deeply flawed notion of PV connector “compatibility.”

To understand why mating different types of connectors is such a problem, it is important to recognize that no universal PV connector standard exists. Each product manufacturer designs and builds PV connectors to its own specifications. Housings from different vendors are made out of different materials; the electrical contacts are made out of dissimilar metals; there are no standard product dimensions or tolerances. These differences lead to failures, some of which lead to fires.

Industry experts have long been aware of the problems associated with mating incompatible PV connectors. Incident investigators and first responders have documented these failures in the field. Testing laboratory personnel have studied connector failure modes and root causes. Trade publications and trainers have shined a light on this issue and shared best practices.

The simplest way to meet the NEC 2020 requirements in 690.33, specifically, section 690.33(C), is to ensure that connectors on PV modules are the same type and brand as connectors on MLPE devices and DC string conductors.

Full article here:
solarpowerworldonline.com/PV-Connector-Compatibility


Example via Stäubli, home of the MC4 connector

Two more, well worth the read:
solarbuildermag.com/Cross-Mating-PV-Connectors_Testing-is-Not-Certification

solarbuildermag.com/Best-Practices-for-Eliminating-PV-Connector-Failures
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Old 06-27-2023, 10:15 AM   #8
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Originally Posted by HamSkoolie View Post
What they mean is that the portion of the connector intended to be the HOT side and the portion intended to be the COLD side were put on the cables backwards. It mentioned field installed connectors and that's likely the cause in all such cross connections.

In other words, the two sides are not identical and the side intended to be on the end of the wire coming FROM the PV panel was instead the one intended to be the one that connects to that one.

Hopefully that makes more sense now.

Thanks, Ham. But please see DeMac's response above, and/or the article I linked to. It's actually about minor differences in different brands of connectors, which when used together can allow for water intrusion / arcing inside the connector. Reversed polarity connections would make themselves known right away. This problem, on the other hand, would be insidious. You'd think everything was fine, right up to the point it wasn't.
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Old 06-27-2023, 10:24 AM   #9
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Lol 🤣 Unfortunately, no

The solar industry’s most dangerous misconception might be the deeply flawed notion of PV connector “compatibility.”

To understand why mating different types of connectors is such a problem, it is important to recognize that no universal PV connector standard exists. Each product manufacturer designs and builds PV connectors to its own specifications. Housings from different vendors are made out of different materials; the electrical contacts are made out of dissimilar metals; there are no standard product dimensions or tolerances. These differences lead to failures, some of which lead to fires.

Industry experts have long been aware of the problems associated with mating incompatible PV connectors. Incident investigators and first responders have documented these failures in the field. Testing laboratory personnel have studied connector failure modes and root causes. Trade publications and trainers have shined a light on this issue and shared best practices.

The simplest way to meet the NEC 2020 requirements in 690.33, specifically, section 690.33(C), is to ensure that connectors on PV modules are the same type and brand as connectors on MLPE devices and DC string conductors.

Full article here:
solarpowerworldonline.com/PV-Connector-Compatibility


Example via Stäubli, home of the MC4 connector

Two more, well worth the read:
solarbuildermag.com/Cross-Mating-PV-Connectors_Testing-is-Not-Certification

solarbuildermag.com/Best-Practices-for-Eliminating-PV-Connector-Failures
A very good read, with excellent advice for DIYers-thanks Demac!
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Old 06-27-2023, 11:15 PM   #10
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Thanks, Ham. But please see DeMac's response above, and/or the article I linked to. It's actually about minor differences in different brands of connectors, which when used together can allow for water intrusion / arcing inside the connector. Reversed polarity connections would make themselves known right away. This problem, on the other hand, would be insidious. You'd think everything was fine, right up to the point it wasn't.

I stand corrected. And thanks DeMac for the clarification.

In the field I worked we used the term to mean the installer put the wrong end on the hot. Think SAE two prong with the hot side having the hot wire on the male (exposed conductor) when that side of connector is supposed to be the load.
It seems the term is used in differently in solar connectors.
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Old 06-29-2023, 04:44 PM   #11
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MC4 connectors

I have seen this incompatibility problem. I had high heat at several connections and sure enough different company connectors. In the string I use the connectors, they're all the same panels so no problem with matching. After the strings I solder all connections. I've done this for my house and bus.
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Old 06-29-2023, 07:41 PM   #12
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Regarding grounding, I would be interested to read a survey of how RV and mobile PV systems fare, especially considering their necessarily different grounding protocols.

John
I'm led to believe that these relatively low voltage systems don't require a ground, just proper fusing.

Curious if anyone has a strong opinion one way or the other.
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Old 06-29-2023, 08:21 PM   #13
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I'm led to believe that these relatively low voltage systems don't require a ground, just proper fusing.

Curious if anyone has a strong opinion one way or the other.
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Old 06-30-2023, 03:53 PM   #14
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Originally Posted by HamSkoolie View Post
I stand corrected. And thanks DeMac for the clarification.

In the field I worked we used the term to mean the installer put the wrong end on the hot. Think SAE two prong with the hot side having the hot wire on the male (exposed conductor) when that side of connector is supposed to be the load.
It seems the term is used in differently in solar connectors.

thats what I was thinking too.. and ive seen it far too many times like you mention in all kinds of DC installs.. from lighting to car stereo even..
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Old 06-30-2023, 04:56 PM   #15
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thats what I was thinking too.. and ive seen it far too many times like you mention in all kinds of DC installs.. from lighting to car stereo even..

And then they wonder why there's a blown fuse after they separate the connector. LOL
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Old 07-01-2023, 08:42 AM   #16
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now days with high voltage mppts voltages are high. I run 225v dc from panels to mppt so conduit protection and solid connections are required. I can go as high as 500 volt dc with my mppts. Code also states, at least in Canada, that all non conduit wiring require metal plate before the finished wall. sheet metal works good 6 in higher and lower than the cable run.
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