Watts247 4/2 Combiner Tripping Breaker ?

[MrM1]

In the past year I purchased 2 of the 4/2 combiner boxes from Watts247. System has been up and running about 5 months.
- Array is an 8s4p 365 watt panels
- Goes into 2 Watts247 Combiners. 4s into 1, 4s into the other
- 2p comes out of each, and Each of these 2 go to the Growatt AIO and SCC. Each has 2 MPPTs

About 6 weeks ago we realized we were only producing about 25% power from the array. We checked the combiners and 3 of the 4 breakers were tripped. 2 in one box, 1 in the other

Why might they have tripped?

Here in Florida, we know a few days before this happened we had violent thunder storms in the area.

It has since happened 2 more times in the past 6 weeks, but again, it has been very stormy as it is that time of year.

I know the Combiners have built in Surge / Lightening suppression. Could high volume electrical storms be causing the breakers in the combiners to trip?

What might be causing the breakers to trip in an otherwise normally functioning Growatt 12k system that has no trouble operating at full capacity

 

[Brett V]

If the surge arrester is on the combined output, it's entirely possible lightning may have tripped them. When you've reset the breakers and discover they've tripped again, is it always the same breakers? If so, you could try switching wires between one that trips and one that never has...see if the problem persists with the same breaker or follows the string.

 

[MrM1]

If the surge arrester is on the combined output, it's entirely possible lightning may have tripped them. When you've reset the breakers and discover they've tripped again, is it always the same breakers? If so, you could try switching wires between one that trips and one that never has...see if the problem persists with the same breaker or follows the string.

Good thought

I'm not on site but I'm checking into this

 

[Brett V]

Basic troubleshooting...it can be a little tedious but follow a process and you'll narrow it down.

 

[Rednecktek]

Could be a weak breaker, swapping will detect that. Could be just a case of really good production.

 

[WattAboutThat]

Would like to know once you resolve.
I am planning on purchasing these for my system.

 

[MrM1]

I'm also waiting on a response from Watts247

 

[WattAboutThat]

Any updates on this issue???

 

[MrM1]

Watts247 finally just today wrote for me to check the input voltage of the combiner. Said it was rated for 63v. I think they meant 63 amps. I wrote them back for clarification

 

[MrM1]

And another update from Watts 247 just now ...

Hi Michael
Yes I meant amps
the combiner box will handle 550 vdc and 1000 v surge.
You will be just fine on all your numbers for your PV.
Hope this helps.

Still does NOT answer my question ... Why did the Breakers Trip. Could it be lightening? I have not been to the farm since this started. I plan to e out there soon to try and diagnose any issues.

 

[WattAboutThat]

And another update from Watts 247 just now ...



Still does NOT answer my question ... Why did the Breakers Trip. Could it be lightening? I have not been to the farm since this started. I plan to e out there soon to try and diagnose any issues.

I am about to purchase 4 of these
and waiting to see if there is an issue
or if it is easily diagnosed

dont want to spend the $$ if
design issue or component issue

thx

 

[MrM1]

We still have not resolved it. But it is lightning season. It has been the same three Breakers though each time. They have fuses before the breakers. The fuses are not blowing. Then there is lightning suppressors before the breakers. So I'm not sure if it's the surge lightning or something else. But we're not seeing anything DC arcing. Everything is just running into a metal pole barn.

 

[MrM1]

So the panels are rated for 11.07 ISC and 10.52 max power.

4s increases voltage so no problem there as We are not exceeding 250v voc

4p gets us to 44.28 amps, so not exceeding the main combiner box breaker rating of 63 amps

So next we remove the breakers swap them around. See if the issues stay on the same strings or follow the breakers. Check connections, check for burn marks and temp issues.

 

[meetyg]

Could possibly be the SPDs. Maybe check them: If you have continuity between either positive or negative and earth/ground, they are faulty. Is the window if the SPD red or green?
I've seen some teardowns on YouTube of these types of SPDs. Basically, they only conduct positive or negative to ground if the voltage is high enough (like when lightning strikes). Usually these surges should only last a few milliseconds at most, but can be lethal to electrical equipment.
In the case that the surge lasts more than that, this will cause overheat of a built in "fuse" (usually just a spring loaded bar soldered to the internal terminal). When this happens, the little window should turn red.

But...
As these teardowns have shown, some of these SPDs do not disconnect properly or sometimes partially. This might cause all kinds of problems. If I'm not mistaken, the MOV in them (metallic oxide varistor) might be a dead short once it's "ruptured" by high voltage. That's why these types of SPDs should always be used AFTER a fuse and/or breaker.

 

[MrM1]

I'll check. But I am pretty sure the design which is both fuse and breaker in these boxes has the SPD between the two. I guess if they are bad we could upgrade them to Midnite Solar SPDs

 

[MrM1]

Update from Watts247

Hi Michael

The surge in ambient energy may be enough to trip the 63A breakers. The common denominator in the issue you are having is "Lightning". Do you have your array grounded? Is the Combiner box grounded?
Need be, give me a call or text and if I'm not available I'll call you back.

 

[MrM1]

The answer to Watts247s questions are "yes". All grounded . Single point. Double rod 6 ft apart tied with #6