diy solar

diy solar

DON'T Install DC Isolators on Solar

Hedges said:
Always chock the tires before crawling underneath. Don't trust the brakes to keep it from rolling when your life depends on it.

US NEC and electrical safety, I think "Isolators" including circuit breakers are suitable to disconnect wires for human contact. Supplemental protectors look like breakers but don't provide same level of protection, which includes 1" gap between conductors fed from grid and the circuit you're going to work on, so a larger contact space inside than you might expect. Typical toggle switches don't provide that. (A visible, necessary if not sufficient, are longer plastic wings around terminals of breakers.) Then you lock-out tag-out.

An isolator doesn't have to be able to interrupt flowing current, but a breaker can do both.
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Oh man, talk about beating me at my own metaphor game! You’re absolutely right that isolation has its place for maintenance.
In my professional life I work in Heavy Industrial facilities and I’ve been through enough safety training that working on my own system without the ability to ‘lock out, tag out’ makes me pretty uncomfortable.
 
timselectric said:
I use DC breakers for my PV disconnects. I don't want to worry about anything.
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I agree. DC isolator with overload protection. Avoid the unknown brands at all cost. I normally go for Noark , Chint , Hager , Gewiss , Schneider amongst a few other reputable brands.
 
On a slightly different note : How many of you installed a proper fire extinguisher , rated for Li fires , near your batteries as well as a smoke detector ?
 
Pierre said:
On a slightly different note : How many of you installed a proper fire extinguisher , rated for Li fires , near your batteries as well as a smoke detector ?
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Me its not required for where i am it just makes me feal safe.
 
JRH said:
saving money can be a great thing on somthings , sometimes …BUT the real deal IMO switch is only about 100 bucks… why would anyone be trying to save money on somthing so important and is already cheap…
I am constantly amazed by people pinching pennys on safty equipment….

why not discount parachutes …?
Discount Heart surgeons …?
Re-man or 3rd tier body armor..?

where does it end…? haaaa

J.
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Some rather extreme examples there lol. Let's not buy a used DC isolation/disconnect switch... but does that necessarily mean that the most expensive option is the best and safest??

By that reasoning you shouldn't even do DIY, you would get the professionals.

In the aforementioned fires, I have at least a suspicion that in one case, the person who had the victron equipment did not get his DC breaker from Aliexpress (not that the DC switch was shown to be the cause but my thought is that they didn't cheap on equipment, the fault lay elsewhere).
 
Zwy said:
An IMO is rated for switching under load, let's clear up any misconceptions or confusion some might have about the IMO. If you don't believe it, then contact the fella in this video and maybe he will clear that up for you.


As for the original video I linked and the following video in the next post, it mentions that if an inverter or isolator has RSD, then the addition of another isolator is redundant and not needed. If you have a string of panels like most of us do on a ground mount without any method of shutdown, then yes, you will need to add an isolation device for disconnect. I think some of the manufacturers of micro inverters and isolators are pushing for this to be in the code to increase the sale of their devices.

If you have rooftop solar, you are required to have isolation to meet the disconnect requirements for fire fighter safety at the module level. Ground mounts do not have to meet this requirement. Preferred method to keep costs down is still ground mount, for me it is not a hard decision to make. Those with limited real estate most likely will have to use roof mount and meet those requirements.

In AU, the requirements are different, this post here shows what they have been doing in the photo. https://diysolarforum.com/threads/solar-economy-is-it-healthy.72148/post-959326 In the following post, it was stated that Finland had changed the requirements for rooftop isolators.

This post relates the majority of fires on rooftop PV was caused by isolators. https://diysolarforum.com/threads/solar-economy-is-it-healthy.72148/post-959636

From what I have seen thus far, it appears the manufacturers of RSD devices are pushing for rules to use their devices, even if those devices cause the majority of fires. As for fires related to devices that copy the IMO, I would say those devices were not made to the standard the IMO meets. These are the import copies most people purchase to save a buck.
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Apologies, I mentiond IMO but I meant in My Opinion. I'll stay away from the abbreviations.
 
LuxOfTheIrish said:
Some rather extreme examples there lol. Let's not buy a used DC isolation/disconnect switch... but does that necessarily mean that the most expensive option is the best and safest??

By that reasoning you shouldn't even do DIY, you would get the professionals.

In the aforementioned fires, I have at least a suspicion that in one case, the person who had the victron equipment did not get his DC breaker from Aliexpress (not that the DC switch was shown to be the cause but my thought is that they didn't cheap on equipment, the fault lay elsewhere).
Click to expand...

thanks for expressing your opinion …and you have a nice day…!
 
LakeHouse said:
You’re absolutely right that isolation has its place for maintenance.
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The key point I'm thinking about is that "off" isn't "isolated". Gap between contacts for some switches is quite small. For grid AC circuits rather than the PV HV DC this thread is about, I could imagine transients jumping across. Or, a relay might switch momentarily if knocked hard. When I see "transfer switches" that are just a relay between grid/generator, I don't like those.

The things that meet NEC or UL listing as "isolators" have 1" gap, much more than the creepage/clearance between conductors we have to use in design.

RSD is meant for fireman safety, but I wouldn't consider sufficient for touching conductors. I don't trust electronics for human safety.


LuxOfTheIrish said:
By that reasoning you shouldn't even do DIY, you would get the professionals.
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"Professional" meaning someone who gets paid for doing the work, is in a hurry so as to maximize profits/pay and to get home?
We end up with the lowest standard acceptable to anyone that way.

On the other hand, DIY can also be badly done.

I think those of us who care, understand, and take the time rather than having to make a living and keep up with the rat race and do the work well.
 
This video doesn't explain WHERE the isolators which failed were located, which is pretty important. It makes no sense to NOT have isolators on your PV strings if your inverter doesn't have a built in PV isolator, as otherwise, in order to remove the PV cables from the inverter itself, or to insert them into the inverter, you would have to disconnect an MC4 connector elsewhere, most likely up on a roof, ensuring your inverter is turned off first.
Surely the answer is to use better quality disconnects, the problem lies in using equipment outside that isn't sufficiently waterproof, or equipment that isn't up to the job intended for it.
 
Zwy said:
Only if you want to see an arc.
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I would add, if you cover enough panels, it would be safe. I say this cause I know there is allot of folks running redneck solar setups that do not have all the safety gear. Just cover your panels when you make or break a connection and there will be no arc.
 
Again what's the consensus on use???

Avoid disconnecting under load even though it's clearly designed for it ??

Avoid outside usage or rooftop (nothing personal here, *I* currently have one outside)??? Says IP66-67 waterproof blah-blah but nothing I can discern about UV protection or resistance.

Could you mount these "under the lid" in a NEMA 3R or 4 enclosure and still have it qualify as "Emergency Disconnect" type status?? Rated 45C ambient in IMO enclosure BTW. Most rooftops are gonna be OVER that...
 
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