ProtonWH
New Member
I'm wondering how switch ratings work. If I send higher DC voltage but lower amps for the switch is this acceptable? I'm wanting to send 300vdc at 12A through a switch rated at 48vdc and 300A...
Calling all Sparkies
- Thread starter ProtonWH
- Start date
Absolutely not...
DC breakers are voltage SPECIFIC for arc protection.
BOTH amps and VOLTS must be adhered to.
ProtonWH
New Member
Still trying to "design" a 2 inverter system where I could switch the PV from one inverter to another manually.
ProtonWH
New Member
That's the concise info I appreciate, Thanks!
ProtonWH
New Member
(without buying 2 switches...) and no way for both inverters to be fed PV
Yeah, the panels COULD be isolated first, the switched, then reconnected...
The issue is BREAKING the connection under load.
So, IF you shut down panel output before you switched it would work...
If you tried switching without shutting down, you would destroy thw selector contacts, and possibly cause a fire...
Also, the insulation rating would have a dangerous situation.
200V DC is NOT something to play with.
The issue is BREAKING the connection under load.
So, IF you shut down panel output before you switched it would work...
If you tried switching without shutting down, you would destroy thw selector contacts, and possibly cause a fire...
Also, the insulation rating would have a dangerous situation.
200V DC is NOT something to play with.
ProtonWH
New Member
OK, sounds like I need to find out somehow then if the two inverters I have my eye on will ac couple...
Last edited:
No.
I am saying if you use a pv selector switch rated lower than the voltage you use, it could possibly work if you have ANOTHER switch on the pv lines that IS rated for the right voltage, turn OFF the PV THEN switch inputs, THEN turn PV back on...
BUT the insulation on the lower rated selector may expose the high PV voltage as a shock hazzard, AND if ever selected under load could be a fire hazard as well.
ProtonWH
New Member
Hedges
I See Electromagnetic Fields!
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I would use a 600VDC safety switch to interrupt the PV circuit, open the interlocked cover, swap MC connectors from one inverter to the other.
(I'm using rubber MC3 connectors, not locking MC4.)
I've been doing that inside a combiner box, no interlocked lid, so I have to switch off elsewhere. Eventually I'll use a switch like the one below, routing PV to my workshop or to installed inverters.
Best to bundle pairs of connectors together , reduces mixups.
(I'm using rubber MC3 connectors, not locking MC4.)
I've been doing that inside a combiner box, no interlocked lid, so I have to switch off elsewhere. Eventually I'll use a switch like the one below, routing PV to my workshop or to installed inverters.
Best to bundle pairs of connectors together , reduces mixups.
Warpspeed
Solar Wizard
Another alternative would be one of the Gigavac vacuum relays:
https://www.sensata.com/products/relays/high-voltage-relays
It will be expensive bought brand new, but they come up on e-bay quite often as they are commonly removed from electric vehicles, and are used to isolate the high voltage dc battery. These are rated to reliably switch hundreds of dc volts, and carry hundreds of dc amps.
https://fastron.com.au/products/gv2...MIzY2u3qmmggMVjCSDAx3cYAjSEAQYAyABEgIrUPD_BwE
https://www.sensata.com/products/relays/high-voltage-relays
It will be expensive bought brand new, but they come up on e-bay quite often as they are commonly removed from electric vehicles, and are used to isolate the high voltage dc battery. These are rated to reliably switch hundreds of dc volts, and carry hundreds of dc amps.
https://fastron.com.au/products/gv2...MIzY2u3qmmggMVjCSDAx3cYAjSEAQYAyABEgIrUPD_BwE
Why are you trying to do that?
ProtonWH
New Member
Trying to figure a way to not buy a SA 15K and keep my project at $1 @ W.
I would simply use 250Vac 16A relays driven by electronic lockout circuit that monitors current and state of inverter AC output or in the case of all in one inverter you can monitor PV input current. Configure switching logic this way: on signal to switch over send inverter disable signal to both inverters, check PV current, if zero then send signal to switch inverter inputs. You can also add properly rated TVS diode across PV conductors to limit inductive voltage spike if you do accidentally end up switching under load but that may still arc and destroy relays. Make sure to house this switching unit inside fireproof metal box. Best route would be to go with solid state switch using high voltage mosfets but at higher complexity.
ProtonWH
New Member
Trying to design at component compatibility level system that is grid tied- sell power after the second hybrid inverter charges my batteries, but if an extended outage I wanted to island with a transfer switch and switch PV over to the second hybrid off grid inverter...
Warpspeed
Solar Wizard
Here you go, e-bay 66 US bux.
https://www.ebay.com.au/itm/2040951...1HLC3hM9O5+w/Akfs/hsW/Wg==|tkp:Bk9SR5rlmqLyYg
https://www.ebay.com.au/itm/2040951...1HLC3hM9O5+w/Akfs/hsW/Wg==|tkp:Bk9SR5rlmqLyYg
ProtonWH
New Member
Very cool, thanks!
Warpspeed
Solar Wizard
Its really the only SAFE way to do this.
If you can figure out a way so it never has to normally switch at very high power, that would be best.
But if it ever does have to switch at high power, you know it can do it without burning both itself and your home down.
If you can figure out a way so it never has to normally switch at very high power, that would be best.
But if it ever does have to switch at high power, you know it can do it without burning both itself and your home down.
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