Problem with Combiner Box

[Dennis 1]

I'm having an issue and cannot figure it out. I have 4 - 100W Rich solar panels (VOC 22.6V & ISC 5.86A) connected in series and 4 - 100W HQST solar panels (VOC 21.6V & ISC 6.5A) connected in series going to a 6 string Midnight Solar Combiner Box.

When I test them the wires coming into the combiner box (see 1st photo) with my multi meter the Rich panels are at 79V and HQST panels are at 82V, they hook to the bottom of 2 - 15A breakers one for each line, when they come out the top they both hook to the bus bar (silver plate at top) they test -0.03V. The lightning arrester on the side of the combiner box is not lit up now either. I have 10 guage wire and go about 30 feet to the house and all the connections are tight, I use 6 guage wire going to each panel and then to a ground rod put in just for this.

Before I hooked 4 in series I had 3 sets of 2 in series then got 2 more HQST panels. The 3 sets seemed to be working fine and my Epever CC was working good but it only could handle 6 panels and thats why I got the new HQST one it can handle 800W.

When I test the lines coming into the house and come into my circuit breaker shut off for the panels that go to my CC (see 2nd &3rd photos) they are at -0.03V and the CC is not showing panels charging the batteries at all.

Hopefully someone can help, keep in mind I just DIY and I'm not an elecrtician so any help would be appreciated.

 

[Hedges]

Maybe one string is backwards, despite your phasing tape.
Maybe polarity is backwards at inverter and it shorts it, but usually that is through a diode, shows 1V to 2V drop.

Turn all breakers off.
Check voltage and polarity from busbar to PV input of each Midnight breaker.
If same and correct polarity and similar voltage, close those breakers and check again.
Check voltage busbar to the bar after the two breakers.

Other box, check input voltage and polarity to 63A breaker.
If correct, close breaker and check again.
If still correct, check output of breaker.
Check input to charge controller.

 

[littleharbor2]

Take your multi meter and start at the PV input terminals. on the CC Got voltage? If yes, move on to output terminals You can trouble shoot most issues with a multimeter. A DC clamp meter is the next tool you need.
Are all polarities correct?

 

[Hedges]

3 breakers, 2^3 = 8 possible combinations of positions.
Those can provide a valuable debug tool.

Yes, clamp ammeter is useful too.

 

[Dennis 1]

Maybe one string is backwards, despite your phasing tape.
Maybe polarity is backwards at inverter and it shorts it, but usually that is through a diode, shows 1V to 2V drop.

Turn all breakers off.
Check voltage and polarity from busbar to PV input of each Midnight breaker.
If same and correct polarity and similar voltage, close those breakers and check again.
Check voltage busbar to the bar after the two breakers.

Other box, check input voltage and polarity to 63A breaker.
If correct, close breaker and check again.
If still correct, check output of breaker.
Check input to charge controller.

Everything with the box with the 63A breaker and the CC checked out good. The problem seems to be the combiner box the lines coming in from the panels to the bottom of the breakers test 80V but when they go out to the top bus bar they test 3.4V. I didn't know where to go from here.

 

[Dennis 1]

Take your multi meter and start at the PV input terminals. on the CC Got voltage? If yes, move on to output terminals You can trouble shoot most issues with a multimeter. A DC clamp meter is the next tool you need.
Are all polarities correct?

The issue to me is out at the combiner box with the wire going to the bottom of the circuit breakers being 80V. But when it goes out the top to the busbas it is at 3.4V. Then it goes from there into the house and everything in there the CC and the 63A circuit breaker tests 3.4V same as the combiner box.

 

[timselectric]

Reset the breakers?

 

[pvgirl]

Have you turned off the breakers in the combiner box one at a time and measure voltage at the bus bar? Disconnect wires from the breakers and the negative bar and verify polarity matches the colored tape.

 

[Dennis 1]

I was wondering I did put ferrules on the wire which was not there in the past do you think this could be an issue. It's raining now but I will let you know how it turns out when I cut them off.

 

[Hedges]

Doubt it is a ferrule.

Either an open circuit or more likely a short.
Open all breakers. Test after PV breakers, one at a time. Then test after 63A disconnect breaker.
With breakers open, confirm no voltage first, then check for shorts on ohms scale.

 

[Hedges]

Or reverse-polarity at the inverter.
Or shorted by the surge arrestor (resistance check should show).

I was going to say Check voltage rating of surge arrestor, but your PV is 80V, and none of the Midnight units are too low for that.

"go to my CC (see 2nd &3rd photos) they are at -0.03V"
"But when it goes out the top to the busbas it is at 3.4V. Then it goes from there into the house and everything in there the CC and the 63A circuit breaker tests 3.4V same as the combiner box."

Don't expect 3.97V drop across the wires.
Negative (-) 0.03V? As in reverse polarity? More likely another way to say zero.

After intermediate steps, try disconnecting one wire from CC and repeat tests.

 

[patrickparrott]

I am assembling the very same combiner box and breakers. It sounds like the lightning arrestor has failed or the system hit with lightning. After all the light is not on, and the power is not leaving the array breakers. See what you get if you disconnect the arrestor.