How hot is to hot? Combiner box
- Thread starter 42OhmsPA
- Start date
Any significant heat spot is a point needing attention.
The fact it is 130 on that screw, but nowhere else on the circuit says to me the device has a bad connection, not a bad wire
The fact it is 130 on that screw, but nowhere else on the circuit says to me the device has a bad connection, not a bad wire
42OhmsPA
What's in a title?
I'm going to skip the fuse holder and go straight to the breaker for piece of mind until I get better fuse holders.
This was the wire I replaced.
This was the wire I replaced.
Wire looks fine, the connection in thw holder must be bad.
42OhmsPA
What's in a title?
400bird
Solar Wizard
Copper conductors both heat and electricity, so a bad connection or bad fuse holder will cause the wire to get hot.
Did you try loosening and retorquing the clamp screw? If so, I'd pop open the fuse holder to see what's inside.
Did you try loosening and retorquing the clamp screw? If so, I'd pop open the fuse holder to see what's inside.
42OhmsPA
What's in a title?
One thing to note is I did split the holder apart, it was 3p. That shouldn't have had any impact at all since it was just a pin holding them together, nothing to do with the wire connection.
42OhmsPA
What's in a title?
Yes, no difference before and after replacing the wire as well.
I was having issues blowing 20A fuses a few days / weeks back but figured that was because I was running ~22A through them. I used a 25A I ordered the other day and figured I'd check temps after the recent fire thread...
Everything with the holder appeared fine.
I'll get some Midnite holders on order and see if they make a difference.
400bird
Solar Wizard
Why are the spec on the front (32a @ 690vac) vs the side (30a @ 750vac)?
Is that fuse holder rated for DC? It probably doesn't matter it's just a fuse holder, the fuse is the important part.
Pics of the inside?
What current was the constant current running through it and the fuse rating?
Is that fuse holder rated for DC? It probably doesn't matter it's just a fuse holder, the fuse is the important part.
Pics of the inside?
What current was the constant current running through it and the fuse rating?
400bird
Solar Wizard
I see you posted the answer to my current question just as I was asking it.
22 amps continuous throughout a 25 amp fuse, is likely the problem. A fuse is a resistor and creates heat to melt and blow.
Normal recommendation is to run a fuse at a max of 80% continuous. Stepping up the fuse to 30 amp would be the minimum to meet that spec.
Was the other holder doing the same current?
TomC4306
Solar Obsessive
I had a similar issue at the breaker.
Was getting hot enough to trip it .
I THOUGHT I was able to 'torque' the screw down with just a screwdriver in my hand but went ahead and put a bit holder and bit on my torque wrench.
More than half a turn later, the issue iwas fixed.
Was getting hot enough to trip it .
I THOUGHT I was able to 'torque' the screw down with just a screwdriver in my hand but went ahead and put a bit holder and bit on my torque wrench.
More than half a turn later, the issue iwas fixed.
TomC4306
Solar Obsessive
I also removed the big diodes with heat sinks in my combiner because they produce a lot of heat in a sealed box.
Swapped in a bus bar.
Swapped in a bus bar.
42OhmsPA
What's in a title?
That's a good question.
According to the Amazon listing, yes.
Can't get much without breaking it open.
I see you found it.
No. The other strings (roofs) are running around 340V 9A at peak conditions but are combined after the fuse.
The ground mount fuse in question is paralleled at the array.
Attachments
42OhmsPA
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I'm confident they are tight enough.
If I go any tighter I'll break something.
I could see the plastic flexing when tightening...
I was able to get another ¹/⁵ a turn on the other connections that aren't getting hot.
42OhmsPA
What's in a title?
I'll order some 30A fuses to go with the midnite holders.
