New Growatt ES5000 safety issue?

[justinjja]

Maybe I just missed it when all the other Growatt safety stuff was going down last month,
But I just noticed something I wasn't expecting with my Growatt ES 5000(USA)

I believe this is an artifact of originally being an EU design.

Both the Solar panel + and - inputs are connected directly to the "Neutral" output. (Neutral being a 120v hot leg in usa wiring)
In the EU that would be Ground,
In the USA that means you have 120v AC potential from Earth/Ground/USA Neutral to both of your DC solar panel wires.

This is safe as long as you know about it...
But if you don't know about it, I could see you getting into a situation where you turn off your DC breaker at your solar panels, leave your inverter on,
and try to start working with those "unenergized" DC wires between your breaker and your inverters solar input.
Zap...

 

[TorC]

That doesn't even make sense. If both PV+ and PV- are connected then it's shorting the panels. Neutral in the US is the ground potential, bonded at main panel, center tap return current carrying conductor for one side of the 240V single phase, center tapped supply. It's generally prudent to be careful touching the neutral in a US system, but it shouldn't zap you.

IIUC, it's common for PV- to also be bonded to a ground potential reference. Please try to explain what the problem is in more detail.

 

[BentleyJ]

That doesn't make any sense, both solar wires cannot be connected to ground its a dead short as TorC says. At the most only 1 wire, usually the negative is connected to ground BUT ONLY if the inverter manufacturer specifies so. In many cases the Inverter installation manual states that neither the + or - solar should be connected to ground. The problem is that many people are comparing the DC side of solar to an automobile and believe this means that the solar panels and inverter are not supposed to be grounded. That is NOT true, any metalic mounting hardware as well as the aluminum solar panel frames and inverter cabinet still need to be grounded. Its just that the + & - DC input in the inverter is isolated and does not need to be tied to ground.

 

[Bud Martin]

Maybe I just missed it when all the other Growatt safety stuff was going down last month,
But I just noticed something I wasn't expecting with my Growatt ES 5000(USA)

I believe this is an artifact of originally being an EU design.

Both the Solar panel + and - inputs are connected directly to the "Neutral" output. (Neutral being a 120v hot leg in usa wiring)
In the EU that would be Ground,
In the USA that means you have 120v AC potential from Earth/Ground/USA Neutral to both of your DC solar panel wires.

This is safe as long as you know about it...
But if you don't know about it, I could see you getting into a situation where you turn off your DC breaker at your solar panels, leave your inverter on,
and try to start working with those "unenergized" DC wires between your breaker and your inverters solar input.
Zap...

That has to be an error.
Can you provide the link that shows it connected like that?

 

[justinjja]

It’s possible to pass AC without shorting DC, just takes a capacitor.

And it’s highly likely to design a dc solar input with a capacitor across + and - if you think about it.

If you have one, all I did was measure AC voltage from the inverter case(earth gnd) to solar + and solar -, both show 120v.
Between solar + and solar - is 0v ac, so that’s how I know it’s the same leg.

 

[Bud Martin]

What you are seeing is due to the safety X cap (very low capacitance in pF range) and also stray capacitance between the hot side and the cold side of the circuit, it is used for reducing EMI.
The current will be very very low due to the Xc of the cap.
And yes, there is bank of lytics caps on the input of the PV input.