and as the systems age, the faults start to appear. This is what happens when you use AC isolators ofr DC circuits, it's taken 5 years to show, but the customer is very lucky that the isolators and inverter were mounted externally in a box.
Shoddy solar work
- Thread starter binky
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ohh jeez..
I can see that happening a lot due to the rushed nature of PV installation over the past few years, then you got the battery mob to contend with.
Should keep you busy for the next few year's.
I can see that happening a lot due to the rushed nature of PV installation over the past few years, then you got the battery mob to contend with.
Should keep you busy for the next few year's.
Sharpend
"It Just Is"
This is the result of the chase the money campaign we have had for so many years, now we will have to start doing things properly again!
that mangled mess of cables is still live with about 450V DC on the cables......making safe was fun, very careful snipping with insulated cable shears and an odd spark. It even sparked when I cut the +ve DC cable, just between the cut ends.
Needless to say the charlatans what fitted this have gone, and the customer isn't getting much response from the third party insurance either (they seem to have disappeared also - frik knows how). The only reason I am keeping my MCS is for the repair work - it's increasing all the time.
Needless to say the charlatans what fitted this have gone, and the customer isn't getting much response from the third party insurance either (they seem to have disappeared also - frik knows how). The only reason I am keeping my MCS is for the repair work - it's increasing all the time.
Installers have long gone,
wish I could Duck, was considering going back after dark.
wish I could Duck, was considering going back after dark.
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Okay that's a charred mess. But how was it the fault of the isolator?
In the "on" position, I can't see it makes any difference whether it's ac or dc passing through it. The only time I can see a problem is if you tried turning the isolator off at mid day on a sunny day, and then there may be a problem with arcing as there's no zero volt crossing to quench the arc.
My money is just shoddy workmanship and lose terminals.
In the "on" position, I can't see it makes any difference whether it's ac or dc passing through it. The only time I can see a problem is if you tried turning the isolator off at mid day on a sunny day, and then there may be a problem with arcing as there's no zero volt crossing to quench the arc.
My money is just shoddy workmanship and lose terminals.
Don't forget that an AC iso will not carry as much current as a DC iso, i.e. not all AC iso's are RMS rated, so if this one wasn;t then it would not necessarily take the full load current of the panels.
Some are, but, not all.
The break gap is often achieved for 2 pole dc by using a 4 pole ac iso, so you double break the supply, this prevents the arc drawing and gives the needed contact seperation.
Trouble is not all of the solar installers knew this.
So they would remove the doubling up links and just use 2 poles, then you have issues with isolation.
However, I do suspect that it is just a poor termination.
Some are, but, not all.
The break gap is often achieved for 2 pole dc by using a 4 pole ac iso, so you double break the supply, this prevents the arc drawing and gives the needed contact seperation.
Trouble is not all of the solar installers knew this.
So they would remove the doubling up links and just use 2 poles, then you have issues with isolation.
However, I do suspect that it is just a poor termination.
leesparkykent
Well-known member
Them ABB rotary isolators are designed for DC as well, they normally have black links between terminals. I'm guessing the links were removed?
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Yeah, take out the links, then we can put 2 strings in 1 iso = Even Worse!!
Canoeboy said:
Can't see why you would, but I could be wrong. Just repair, test, commission is my view on it.
leesparkykent
Well-known member
Yeah I've seen 2 strings in one of those isolators before with the links removed :yellow card lol. I've also seen pics before of the same isolator that caught fire whilst being turned off, it turned out the links had been removed from that one as well.
Moons ago I tried to stop a DC motor on its isolator, not one of my better ideas. The arc just carried on across the switch until the switch caught fire, flashed across and blew the fuses.
One of the places I worked used 11kV load break switches for the 660V DC motor isolators. Supposedly so you could stop the drive on the isolator, to hell with that!
If you get a fault DC is evil.
One of the places I worked used 11kV load break switches for the 660V DC motor isolators. Supposedly so you could stop the drive on the isolator, to hell with that!
If you get a fault DC is evil.
