Unqualified Persons and PV Arrays

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Anode

Member
Location
Washington, USA
The question I have is on cleaning solar systems.

Should we as contractors advise against having unqualified personnel clean a solar array?

How about unqualified personnel cleaning a solar array that is not energized?

Or even better, one that has no high string voltages present, like a microinverter system setup, or a Solaredge system in safe mode.

Would those scenarios be okay in your opinion to advocate building personnel or homeowners to clean their systems?


With respect to safety, and therefore the fundamental principals of the NEC, should we really be advocating owners to clean a system by their own means?
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
The question I have is on cleaning solar systems.

Should we as contractors advise against having unqualified personnel clean a solar array?

For electrical reasons? I think that's overkill. Because of fall hazards? Yes.

How about unqualified personnel cleaning a solar array that is not energized?

You mean do the cleaning at night? :cool: Doesn't seem like a good idea. I don't think a non-energized-during-the-day array exists. :p Unless you mean...

Or even better, one that has no high string voltages present, like a microinverter system setup, or a Solaredge system in safe mode.

There's something to be said for turning off such a system, or any system, while cleaning. Certainly the ones you've mentioned are safer, electrically.

Would those scenarios be okay in your opinion to advocate building personnel or homeowners to clean their systems?

Again, fall protection concerns me most. More than electrical, while recognizing that electrical also can contribute to fall hazards.

With respect to safety, and therefore the fundamental principals of the NEC, should we really be advocating owners to clean a system by their own means?

Well, I don't know that we should advocate it. I often have told customers that their systems don't need cleaning, that the financial returns aren't worth their time or paying someone else, let alone the risks. The rain will wash them off as much as needed. Of course it's getting a little harder to make this argument in California because we've had so little rain, but anyway...

I think there's something to be said for qualified window cleaning professionals, who may already have fall protection training, to receive training on the potential risks of cleaning solar arrays if they want to make it part of their business. I can tell you that as a solar installation company, we would not be able to make ends meet if we had the obligation to clean our customers arrays. I don't think its necessary from a safety point of view to create such a burden.
 

Zee

Senior Member
Location
CA
For electrical reasons? I think that's overkill. Because of fall hazards? Yes.



You mean do the cleaning at night? :cool: Doesn't seem like a good idea. I don't think a non-energized-during-the-day array exists. :p Unless you mean...



There's something to be said for turning off such a system, or any system, while cleaning. Certainly the ones you've mentioned are safer, electrically.



Again, fall protection concerns me most. More than electrical, while recognizing that electrical also can contribute to fall hazards.



Well, I don't know that we should advocate it. I often have told customers that their systems don't need cleaning, that the financial returns aren't worth their time or paying someone else, let alone the risks. The rain will wash them off as much as needed. Of course it's getting a little harder to make this argument in California because we've had so little rain, but anyway...

I think there's something to be said for qualified window cleaning professionals, who may already have fall protection training, to receive training on the potential risks of cleaning solar arrays if they want to make it part of their business. I can tell you that as a solar installation company, we would not be able to make ends meet if we had the obligation to clean our customers arrays. I don't think its necessary from a safety point of view to create such a burden.

I agree with Jben.
I think it is best to state the facts, and not advocate it. And the facts are: no need to clean ever. (at least in CA)

2 exceptions:
1. extreme pollution
( e.g dry plowed field adjacent to ground-mounted array).
2. flat arrays.
(less than 5 degree pitch)
(The lip on frame creates what is termed "mud shading".) Have seen.... and it can be fairly bad.

Google did massive studies on this, years ago.
Conclusion: not worth the increase in output. Unless your panels are at less than 5 degree pitch.......which was a horrible idea back in the day.....Any cleaning would have to be so frequent and thorough....it would be too costly to offset the savings. Something like less than 5% annually if cleaned very regularly.......They get very clean immediately then revert to dusty and dirty, like a car.

( I always tell my clients: no need to clean, as winter rains handle that)

The LAST thing i want is a client, way up on a roof, with a water hose near 600 VDC wiring! :jawdrop:

A soalredge system and micro system does present less of a hazard..... and if they wanted i would show them how to shut off such a system. But otherwise...there is no way to de-energize a standard 600VDC array. It can even be argued that shutting off a dc disco on a typical string inverter elevates v to Voc and poses a greater risk!
 

Zee

Senior Member
Location
CA
One more thing:
I always use the following analogy when i hand off a job:
when you squat and look straight across the surface of a polished coffee table you will see any dust..... even a speck. Yet, isn't the table clean enough?
That is how we all view solar panels...from the bottom up, looking at an oblique angle...so they always look way dirtier than they are. Meanwhile, the sun is overhead and shining through 99% of that dust and pollen.
 

PWDickerson

Senior Member
Location
Clinton, WA
Occupation
Solar Contractor
I am going to play Devil's advocate here.

I clean my fridge, range, and dishwasher without de-energizing them.

PV modules are UL listed and if they are installed correctly, what risk is there of cleaning the top surface of an array?
 

SolarPro

Senior Member
Location
Austin, TX
Couple important differences between your customer's fridge and their PV array:

  • First, it's highly unlikely that squirrels are nesting under your customer's fridge or that ice damns or similar could compromised the integrity of the field wiring associated with the fridge.
  • Second, it's highly unlikely that the fridge would present an electrical hazard or continue to operate in the event that its wiring were compromised.

These are also unlikely scenarios to encounter with a PV array. But if you send enough customers up on a roof to clean an array, sooner or later one of them will encounter hazardous conditions along these lines. If anything, I'd write up a contract offering an annual cleaning service at an appropriate time of the year based on local weather patterns, and include a signature line that waives your liability in the event the customer has turned down your cleaning service and decides to clean the array themselves.

Maybe this becomes less of an issue with the new arc-fault requirements and the increasing deployment of ungrounded PV systems. But legacy systems can definitely present unique hazards to unqualified personnel.
 

Electric-Light

Senior Member
Qualified meaning?

If anything, I'd write up a contract offering an annual cleaning service at an appropriate time of the year based on local weather patterns, and include a signature line that waives your liability in the event the customer has turned down your cleaning service and decides to clean the array themselves.

If anything, I'd push for something that disallows contract sales without a qualification and require testing on business and contracting law to be qualified.
 

SolarPro

Senior Member
Location
Austin, TX
In Article 100, qualified person is defined as, "One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training to recognize the safety hazards involved."

Really all 690.4(E) says is that wiring and interconnections must be performed by qualified persons. So if a solar company wants to send its customers up on the roof to hose down a 600- or 1,000-Vdc PV array, there's nothing in the Code to stop them.
 
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mwm1752

Senior Member
Location
Aspen, Colo
The equipment has been listed for the atmospheric conditions it is to be installed in. Cleaning is most likely snow removal & possibly a washing. The hazard is physical damage to the equipment from accidental contact (falling into, dropping tools, or something unexpected) not a purpose washing IMO. A professional installer informes his customer of hazards & maintence. Would be a good idea to have knowledgeable workers clean but not code or listing enforceable.
 

zog

Senior Member
Location
Charlotte, NC
Couple important differences between your customer's fridge and their PV array:

  • First, it's highly unlikely that squirrels are nesting under your customer's fridge or that ice damns or similar could compromised the integrity of the field wiring associated with the fridge.
  • Second, it's highly unlikely that the fridge would present an electrical hazard or continue to operate in the event that its wiring were compromised.

So they need to be trained in Squirrel safety?
 

SolarPro

Senior Member
Location
Austin, TX
The main issue with PV systems is always the 600- or 1000-Vdc shock hazard that is present whenever the the sun is shining. Here's what squirrels like to do when they are nestled up under a PV array. They basically chew the insulation right off the exposed source circuit conductors.
 

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Zee

Senior Member
Location
CA
The main issue with PV systems is always the 600- or 1000-Vdc shock hazard that is present whenever the the sun is shining. Here's what squirrels like to do when they are nestled up under a PV array. They basically chew the insulation right off the exposed source circuit conductors.


:weeping: Wow, never seen it. Good to see.
 

DanS26

Member
Location
IN
LOL.....this thread needs an ounce of common sense. Get real guys..you do not need an electrical license to spray water on an array.
 

SolarPro

Senior Member
Location
Austin, TX
Correct. There is nothing in the Code that requires any kind of license for cleaning an array. And that's completely missing the point.

The question is whether a licensed solar installer should encourage its customers to perform routine maintenance work on their array. You could ask the same thing from the perspective of any contractor. Regardless of what whether you are installing HVAC systems, pools, on-demand water heaters, whole house backup generators, and so forth, you really probably don't want to encourage your customers to perform maintenance activities that could, however slim the chance, put them in harm's way. No one needs that liability. Contractors are better off encouraging customers to contact them for maintenance support.

This is especially true of PV systems because an energized voltage source is always present when the array is illuminated; this is doubly true for PV systems installed prior to the introduction of dc arc-fault circuit protection requirements in the NEC. You really don't want your customers performing maintenance activities?at your urging or with your encouragement?on legacy PV systems. If the customer does the work themselves and gets shocked climbing a ladder because a gutter is inadvertently energized by a broken PV module or a compromised PV source circuit conductor, you don't want to be responsible for sending them onto the roof. (Remember, even if an inverter detects a ground-fault, it can't actually clear the ground fault condition.) If something terrible were to happen, the installation company would want to be able to show that it offered to do the maintenance work for the customer. It's not your fault is the customer opts to do otherwise.

Again, this seems like status quo for any mechanical of electrical equipment. Sure, sometimes I hose off my own HVAC condenser. But the installation contractor didn't encourage me to do that, but instead encourages me to have them perform annual maintenance on the system.

When in doubt?and where possible?minimize your professional risk and exposure. Why do otherwise unnecessarily?

(As the codes and standard progress, this will become less of an issue. But I don't think they've introduced any touch-safe PV systems yet.)
 

Electric-Light

Senior Member
The question is whether a licensed solar installer should encourage its customers to perform routine maintenance work on their array. You could ask the same thing from the perspective of any contractor. Regardless of what whether you are installing HVAC systems, pools, on-demand water heaters, whole house backup generators, and so forth, you really probably don't want to encourage your customers to perform maintenance activities that could, however slim the chance, put them in harm's way.

it sounds like a scare tactic pitch coming from a solar sales guy. May I suggest you hire a full time professional chauffeur to keep yourself out of harm's way that is inherent to driving? It would also pass on liability associated with driving to them.

No one needs that liability. Contractors are better off encouraging customers to contact them for maintenance support.

This is especially true of PV systems because an energized voltage source is always present when the array is illuminated; this is doubly true for PV systems installed prior to the introduction of dc arc-fault circuit protection requirements in the NEC. You really don't want your customers performing maintenance activities?at your urging or with your encouragement?on legacy PV systems. If the customer does the work themselves and gets shocked climbing a ladder because a gutter is inadvertently energized by a broken PV module or a compromised PV source circuit conductor, you don't want to be responsible for sending them onto the roof. (Remember, even if an inverter detects a ground-fault, it can't actually clear the ground fault condition.) If something terrible were to happen, the installation company would want to be able to show that it offered to do the maintenance work for the customer. It's not your fault is the customer opts to do otherwise.
If the result is due to installation company's negligence, having offered to provide maintenance probably wouldn't waive your liability. Ask your attorney. :sleep:

Again, this seems like status quo for any mechanical of electrical equipment. Sure, sometimes I hose off my own HVAC condenser. But the installation contractor didn't encourage me to do that, but instead encourages me to have them perform annual maintenance on the system.
Truth be told, liability is a generic excuse that's not the genuine concern. They're trying to protect the gravy job with the ultimate agenda of protecting service revenue.

When in doubt?and where possible?minimize your professional risk and exposure. Why do otherwise unnecessarily?
Hire a chauffeur. Say bye bye to moving violations. It's only money, right?
 

SolarPro

Senior Member
Location
Austin, TX
I understand that point of view. But very few solar companies rely on residual income from solar O&M activities, especially in residential applications. And obviously you can't get around liability associated with any type of neglect during design or installation. (The way systems are financed today, banks require that long-term O&M contracts be in place for leased systems, which account for more than 50% of residential installations, as well as some types of loans.)

My opinion is really just based on the inherent differences and relative hazard that a Code-compliant conventional dc PV system represents relative to any other electrical system on someone's house. What other electrical systems are likely to remain energized after a ground fault or a bolted-fault in the system? Also, you're not going to fall off your roof when maintaining most other types of equipment.

The good news is that with the increasing use of transformerless inverters, microinverters and ac modules, the hazards that I am concerned about are overblown in systems being installed today. I'd have no problem telling a customer to hose off their PV system if it is built using module-level inverters. But with for systems built with transformer-isolated string inverters, I really don't want customers messing with the array. Those systems may not age well, and could present unique and unexpected hazards due normal wear and tear.
 
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Zee

Senior Member
Location
CA
Well...i may make 100 bucks for a service call. Say it's $200.
Takes 2 hours of my day, door to door. ( drive out, set up ladder, get hose up there, clean and invoice). I can make almost $10,000 in two days installing a system.
And i have plenty of work. Why do you think an installer, like me wants to wash panels, as a licensed electrical contractor?
 

Zee

Senior Member
Location
CA
Some of us don't recommend ANYONE wash them. How is that trying to secure work for ourselves? And that in many cases we do show them if and when safe.
But you know what i am sure you are right in some cases: if you are a newbie/inexperienced solar contractor you may look forward to service calls.....
 
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