How to isolate a panel in a string?

[solarponders]

Hi All,

My configuration is to have 4 panels in 1 string (that is all 4 connected in series). However, I've to disconnect 1 panel from the
string in the colder season due to the danger of spike in Short Circuit Voltage.

My proposal is this :

Have 3 wired in series and connected to a DC breaker/disconnect
And, have the last-to-be-isolated-panel connected to another DC breaker/disconnect
Now, these 2 breakers will be connected in series..

When time comes for the lower temperature, I would just flip the switch on the the 2nd breaker.
The only thing I would gain is that I wont have to go under the panel and pull the plugs ... when it comes to colder season.

Will this idea/wiring work? .. Is there anything I am missing?

Thanks

[Naptown]

This could be done with a simple three way switch. Just make sure you are not throwing the switch when it is under a load unless you can get a switch rated for DC and the voltage range you are in.

Here is a drawing that shows a SPDT thermostat in place of the switch. Again this would need to be rated for DC in order to work properly.

[solarponders]

This could be done with a simple three way switch. Just make sure you are not throwing the switch when it is under a load unless you can get a switch rated for DC and the voltage range you are in.

Here is a drawing that shows a SPDT thermostat in place of the switch. Again this would need to be rated for DC in order to work properly.

Cool, thanks for the 3 way switch .. this is exactly what I was looking for ... without saying as much in the right words.

Btw, I learnt a few other terminologies Single Pole Double Throw, .. Thx

Now what happens when thrown under a load -- is that matter of an electric shock due to arc or the the devices (the load) stop abrupty causing
damages to its circuitry?

[Naptown]

Arcing is the problem with DC current. If you can find a DC rated switch or thermostat it is best.
A zener diode may also be a possibility depending on the size and voltage of the array there is a thread here about that.

[Mike90250]

I would simply use a switch to short out 1 panel

Shorted panels have no troubles.

Or a properly rated themal disk switch. Or a thermal disk switch activating a solid state relay

Arc welding is mostly done with DC, so that's the issue with DC switches - they tend to be very expensive as arcs try to eat them.

[solarponders]

I would simply use a switch to short out 1 panel
Shorted panels have no troubles.

so how is shorting the panel solution different from the Naptown's ... how does the
wiring look like?

and the shorting eliminates the arc?

[Naptown]

No difference really both will take one module out of the string Doesn't eliminate the arc but will reduce it as the voltage will be lower than the potential on the string.

[billvon]

so how is shorting the panel solution different from the Naptown's ... how does the
wiring look like? and the shorting eliminates the arc?

First it means you can use an SPST switch instead of a SPDT switch. You're only switching the OCV of one panel via the shorting switch so DC voltage requirements shouldn't be too bad.

For the other method a make-before-break SPDT switch would solve your arcing problems but they're somewhat rare.

[solarponders]

First it means you can use an SPST switch instead of a SPDT switch. You're only switching the OCV of one panel via the shorting switch so DC voltage requirements shouldn't be too bad. For the other method a make-before-break SPDT switch would solve your arcing problems but they're somewhat rare.

I think I got it. To simplify, we might just get 1 SPST shorting switch. To just verify -

Now, the pole of the SPST will be connected to +ve and -ve of the panel to be isolated right?

And in the (throw) ON position, (UnShorted position) the +ve will be in series with the other panels,

And in the OFF position, (Shorted) the panel will be isolated due to shorting.

I will also try to understand the SPDT make-before-break option ... reading up on it.