DON'T Install DC Isolators on Solar

[timselectric]

Unit price $883.42 ughhh

I use a $16 breaker. lol

 

[rhino]

Also the IMOs go up to 55A.

 

[rhino]

I use a $16 breaker. lol

Which breaker?

 

[timselectric]

Which breaker?

https://a.co/d/12v7jjP

 

[rhino]

Since I had trouble finding this stuff before I'll mention I found somewhat wide selection of IMO isolators/disconnects in stock in the USA at https://www.industrialcontroldirect.com/dc-disconnects-316. They even have the panel mount version so you can install it in a metal enclosure.

 

[Siamac]

I used to turn my IMO off and on a lot when commissioning the system last year…now I rarely turn it off … there’s no reason lately.

The PV panels feed the combiner box …the.combiner box feeds the IMO … the IMO feeds a plastic weatherproof box which has a set of large Anderson connectors (and a MS SPD) which connect to the wire that run 65 ft to the solar trailer and it’s own seperate connection
/ cutoffs / SPD / fuse ….

when working on anything PV related I turn off the IMO and then unplug the Anderson connectors.. now all connections are disconnected from the panels to the solar gear…first with IMO ,then with an absolute wire disconnect , the Andersons.

if I’m going to mess with the actual panels I use gloves …


My IMO has been used about 50 times this summer under some degree of load… it works just fine.…

it is simi - protected from rain and UV , but if the plastic fails every 2-5 years from sunlight, remove the guts and install in a metal Box… OR …..go spend a hundred buck and totally replace it … that what we do with tires, fan belts and hoses… fluids and mufflers.

Can you please explain what this Anderson thing is and how to use it
?

 

[timselectric]

I would like to see a link to the Anderson connector used. And if it's actually rated for higher PV voltages.
Not that it needs to be, if it's never disconnected under load.

 

[JRH]

Can you please explain what this Anderson thing is and how to use it
?

goggle Anderson Connecters .. they are generally beefy connectors to connect ( let’s say) a snow plow to the truck or winch connected… or smaller stuff …it’s a huge markets and a zillion different ones… high amperage capacity 600V on some AC or DC but you need to verify the one you need …
I would help more but you need to at least familiarize your self with them on line to even have a meaningfull discussion..I got all of mine at PowerWorx…. Good company…

good luck jim…

 

[JRH]

I would like to see a link to the Anderson connector used. And if it's actually rated for higher PV voltages.
Not that it needs to be, if it's never disconnected under load.

Tim, I will send you an overview of the model I got…it’s called an SB 175 ..it’s the one of the ones you can use differing wires with 1/0 ( 6 ga + 1/0 …or 2 ga to 1/0) . I got the grey ones .. different colors can mean different things.

I bought all of my Anderson gear and crimps at Powerwerx …online, great place I thought…they have all the specs…and are very knowledgeable…
can’t speak for all of the models as there are too many …but I love using them..

I have never tried to unplug or plug one up under a decent load , but in an emergency i have known people who did… decent sparks can ensue…

Mine are mid sized ones ,I believe they are rated for 175 amps , 600 volts DC. . 10,000 disconnects no load , the 100 amp load disconnect rating is much less,.but I forget exactly.

It doesn’t matter much as in my case they are under no load as the IMO is turned off before they are opened and they are connected before the IMO is turned back on.

i used them for years on my snowplow and gravel spreader connections.. mounted in water proof boxes. . the 1/0 Wire is a bitch to crimp with their special thick lugs…there’s a ton more info on them if one wants to look.
pic follows …
Jim.

 

[JRH]

I would like to see a link to the Anderson connector used. And if it's actually rated for higher PV voltages.
Not that it needs to be, if it's never disconnected under load.

Another pic .. with different specs…

 

[pollenface]

Australia has done a 180 on them too, but most of theirs were fitted up on the roof when they no doubt degraded and started leaking.

There are none on my recent grid tied system, done in may 23 (Perth).

The only DC isolator is on the inverter itself.

 

[timselectric]

Tim, I will send you an overview of the model I got…it’s called an SB 175 ..it’s the one of the ones you can use differing wires with 1/0 ( 6 ga + 1/0 …or 2 ga to 1/0) . I got the grey ones .. different colors can mean different things.

I bought all of my Anderson gear and crimps at Powerwerx …online, great place I thought…they have all the specs…and are very knowledgeable…
can’t speak for all of the models as there are too many …but I love using them..

I have never tried to unplug or plug one up under a decent load , but in an emergency i have known people who did… decent sparks can ensue…

Mine are mid sized ones ,I believe they are rated for 175 amps , 600 volts DC. . 10,000 disconnects no load , the 100 amp load disconnect rating is much less,.but I forget exactly.

It doesn’t matter much as in my case they are under no load as the IMO is turned off before they are opened and they are connected before the IMO is turned back on.

i used them for years on my snowplow and gravel spreader connections.. mounted in water proof boxes. . the 1/0 Wire is a bitch to crimp with their special thick lugs…there’s a ton more info on them if one wants to look.
pic follows …
Jim.

I'm very familiar with them. I have also used them for years. I like them because the contacts are self wiping (cleaning). I didn't realize that they were rated for 600vdc. As I have never needed them for anything above 100vdc. But it makes sense as long as you don't disconnect them under load. (That's scary at just 12vdc)
The lugs are very thick. I have never crimped them. Always soldered them, that's why they have the rolled out rim.
Both connection types are good.
Solder is a better electrical connection, and better in corrosive environments.
Crimped is better for high vibration situations. And is easier to do, in some locations.

 

[Zwy]

Your instl isn't much concern, but others obviously have this on rooftop, on outside of house etc or are planning to do so..We don't want problems tracing back to some DIY Solar folk, now do WE? ?

Remember when you could buy dynamite for DIY until someone effed up ??
View attachment 188983


If we can rethink the way we have done things, I know we all think to ourselves "next time I would change x, do y differently, make it better". Just trying to "work the problem", or at least consider whether it is a problem. It's a darn important little piece of plastic, perhaps...

And great, we agree metal enclosures might be a thing for these!

It's cheaper to just use ammonium nitrate and diesel fuel than dynamite. Farmers have easy access to both.

I don't agree that a metal NEMA enclosure might be a better choice however. The IMO molded case is IP67 rated and NEMA 4.

NEMA 4 alone is only IP65. Plus a poly case is corrosion resistant.

 

[Plum Crazy Rob]

The IMO molded case is IP67 rated and NEMA 4.

NEMA 4X, as you are probably aware. Now if it were only more UV resistant, until we come out and find via a (hopefully no more damage than) melted glob that UV degradation resulted in a loss of of said IP rating and subsequent failure.

Agree, putting it in a metal enclosure is still some concern both in terms of water ingress and perhaps arc safety (?). There was something in the IMO manual about the non enclosed switch itself being IP66 "front face only" = complete BS to me.

 

[Plum Crazy Rob]

Ah, there it is. It's really telling to me that it's UL94 fire rated not to burn...very long. Let's just say outdoors consideration should be given to combustibilty of mounting locations??

 

[Plum Crazy Rob]

I use a $16 breaker. lol

Indoors, right?? Weren't you talking future ground mount?? What would be your plan for array disconnect?? I'd like to see more input from highly respected members, not just Doc (highly respected) and myself (a wildcard no doubt ?)

 

[Zwy]

NEMA 4X, as you are probably aware. Now if it were only more UV resistant, until we come out and find via a (hopefully no more damage than) melted glob that UV degradation resulted in a loss of of said IP rating and subsequent failure.

Agree, putting it in a metal enclosure is still some concern both in terms of water ingress and perhaps arc safety (?). There was something in the IMO manual about the non enclosed switch itself being IP66 "front face only" = complete BS to me.

Electricians around the world install pvc conduit outdoors, you seem to miss that point. It is done for corrosion resistance, your counter argument about "plastic" is really baseless.

The IMO has a flame rating and has been tested.

Ah, there it is. It's really telling to me that it's UL94 fire rated not to burn...very long. Let's just say outdoors consideration should be given to combustibilty of mounting locations??
View attachment 189080

As for the IP rating, it is IP66 for cover and enclosed plastic. It is in the video in the post above but you obviously didn't watch it. If you were to actually hold this in your hand, you would know why it is IP rated.

I have never seen water egress thru solid plastic but in the make believe world some live in anything could be possible. Along with unicorns, fairies and other fantasies.

Look, if you don't want to use one then don't. But trying to misrepresent a product that was designed and tested for the application is just trying to be argumentative. The IMO holds certifications from Ce, UL, cUL, TUV, RCM.

 

[Plum Crazy Rob]

IP66 for cover and enclosed plastic

67 enclosed, thx, I posted that.

But trying to misrepresent a product that was designed and tested for the application is just trying to be argumentative.

Not misrepresenting. I'm saying it fails in the field. ( ) ( <- can you really put a smiley on that?)

Look, I understand your point in starting this topic was to poo-poo the videos / decisions. However it may have surprised you a discussion broke out !

 

[Plum Crazy Rob]

Stop charge and loads on your inverter, then it is safe to disconnect an MC4 to break the circuit.

Looking better all the time. And it was post #5 we could have been done here a loooonng time ago

 

[Zwy]

67 enclosed, thx, I posted that.

It is IP66 for the cover and enclosed plastic. It's in the video you haven't watched yet.

Not misrepresenting. I'm saying it fails in the field. ( ) ( <- can you really put a smiley on that?)

I can assure you the IMO's I have will long outlast the NEMA 4 enclosures I use.

It doesn't fail in the field, only in some people's twisted minds. As I said, don't use it as it will keep you up all night worrying about the plastic failing in 50 years.

Look, I understand your point in starting this topic was to poo-poo the videos / decisions. However it may have surprised you a discussion broke out !

Actually, I found the video interesting and I agree with the video where it states to not install additional isolation if not needed. If rooftop solar is installed with micro inverters or other RSD devices at module level, there is no need to install additional isolation on the roof as was commonly done in the past.

That doesn't mean one should not install isolation at ground level or near an inverter.

Instead of implying that I said something or think something, you should instead think about what you want/need on your system and install it accordingly. There is plenty of information out there to make an informed decision, however you have to look at and understand that available information. Take the video as an example, given the "questions" you asked and various statements, it is obvious you have not looked at that resource.

 

[fourtytwo]

That video way back in post #1 is very misleading. It quotes a fire authority who have no electrical engineering expertise simply based on there observations. I have personally observed in many instances incorrect equipment being used for DC breakers, most typically components designed for use with 440V 3-phase AC circuits and in no way suitable for DC.
IMOP a DC breaker is essential to allow the panels to be isolated ON LOAD from a faulty inverter to prevent fire in same.
However it should obviously be properly rated for the job, environmentally protected and accessible from the ground.
I cannot imagine what idiocy led to fitting of isolators on roofs of normal domestic premises if there is no ground accessible companion.
Now you can all shoot me down, I only spout common sense!

 

[Partimewages]

I would put Isolation anywhere I don't want to climb or walk to. But I'm pretty lazy ????

 

[Plum Crazy Rob]

It is IP66 for the cover and enclosed plastic. It's in the video you haven't watched yet.

Well, this is solved. My apologies to Doc Z and all, the video and manual disagree

Irrelevant after loss of IP integrity anyway. Cracks or housing distortion via UV and loss of enclosure seal between the two halves then pffttt

 

[garetwo]

Yes, they are...read the manual:
IMO switch-disconnector manual

View attachment 188560

This is a good point. I immediately noted the 50 degrees Celsius, or 122 degrees Fahrenheit. We had three days summer 2019 at 121 degrees Fahrenheit, what might the temperature have been within unventilated and exposed to sun enclosures? This is not my main thought.

The main thought is we must know what all aspects of our system may do/create/be exposed to in order to make sure we install components that function as designed in the worst-case scenario – I have failed in this arena. Great reminder, thank you.

I also sent my friend an order of shutdown to isolate components, starting with branch circuit breakers…

 

[Plum Crazy Rob]

It doesn't fail in the field, only in some people's twisted minds.

This thread wouldn't be complete without the oft-repeated terrifying Australian pictures...

None are IMO?? I honestly can't tell in some cases - plus your thread title videos were not "Only install IMO disconnects" ?