Panel disconnect?

[Cory]

I'm looking for a disconnect option between the 1.64kw panels and a Victron 250/100. I have the panels connected in series (four 410w, ~131v & 10amp). What are my options? This in our boondock camper.

 

[Lane]

Any type of switch rated at 20 amperes. A battery knife switch is low cost and easy to install plus quite rugged. Many on Amazon and Auto Zone etc.

 

[JCSchwarb]

IMO makes a decent PV disconnect. I use four of these for a max of 8 strings. Both positive and negative are switched. These cut and apply power with minimal to no arcing and are UL 600 VDC approved.

Industrial Control Direct DC Disconnect 16 Amp 2-Pole Nema 4X Enclosed https://a.co/d/9GflkLr

 

[Lane]

I found 15a toggle switches on clearance at a department store the other day to be used to switch some panels in and out.
I got all they had for abt $3 ea. Good enough for my requirements. These are single pole so I will only switch the pos wire.

 

[JCSchwarb]

I found 15a toggle switches on clearance at a department store the other day to be used to switch some panels in and out.
I got all they had for abt $3 ea. Good enough for my requirements. These are single pole so I will only switch the pos wire.

That approach would not be compliant to NEC guidance. Both pos and neg must be disconnected in a single quick disconnect.

 

[Cory]

I haven't seen many switches that will like 131 volts dc. I know a knife switch will work, but that is a Vincent Price option IMO.

 

[OzSolar]

The IMO's meet the 600v DC rating but they sure feel light duty.

Since you're under 250v you can use one of these from Home Depot. I use the 60 amp to give myself more room to work in but they make the same switch in 30 amp version. Yes, it rated for DC. They have indoor and outdoor versions.

 

[12VoltInstalls]

know a knife switch will work

Only if it’s rated for DC, and 600VDC

 

[MisterSandals]

I found 15a toggle switches on clearance at a department store the other day to be used to switch some panels in and out.
I got all they had for abt $3 ea. Good enough for my requirements.

If these switches are rated for a lower voltage than you are using them for, its very likely that the contact areas will not last. This may "appear" to be working just fine at first but when the surfaces are degraded, the resistance increases, causing more and more heat. This will gradually become a serious fire hazard and will eventually fail in a bad way.

 

[DougfromdaUP]

I wouldn't use a knife switch on a dare, let alone install one! Have you ever seen the arc you can draw with 130 volts dc at 10 amps? When it starts arcing you'll have that plasma spewing globs of molten metal onto skin, in your eyes, through your shoes.
Sometimes there's a really good reason for ratings.

 

[Cory]

I wouldn't use a knife switch on a dare, let alone install one! Have you ever seen the arc you can draw with 130 volts dc at 10 amps? When it starts arcing you'll have that plasma spewing globs of molten metal onto skin, in your eyes, through your shoes.
Sometimes there's a really good reason for ratings.

With all due respect, recommending a knife switch is just mad. I found a nice breaker with a rail.

 

[JCSchwarb]

I wouldn't use a knife switch on a dare, let alone install one! Have you ever seen the arc you can draw with 130 volts dc at 10 amps? When it starts arcing you'll have that plasma spewing globs of molten metal onto skin, in your eyes, through your shoes.
Sometimes there's a really good reason for ratings.

With all due respect, recommending a knife switch is just mad. I found a nice breaker with a rail.

Breaker is not appropriate either for DC solar. Will melt it to the ground. Need to switch positive and negative together with a quick disconnect that is spring loaded, like an IMO.

 

[12VoltInstalls]

Breaker is not appropriate either for DC solar

there are DC breakers of appropriate design and spec

 

[JCSchwarb]

there are DC breakers of appropriate design and spec

I would prefer to see a fuse close to the panel and a proper quick disconnect near inverter(s). Both + and - must be able to quickly be disconnected per NEC.

 

[12VoltInstalls]

I would prefer to see a fuse close to the panel and a proper quick disconnect near inverter(s). Both + and - must be able to quickly be disconnected per NEC.

Yes.

I use fuses at the panels; not a one has ever blown nor do I expect one to blow. But they’re there….

Inside I have 2-pole DC breakers on DIN rail that are essentially disconnects. They are 2A above the panel fuses so other than some bizarre unlikely backfeed event I can’t imagine one them tripping.

proper quick disconnect near inverter

??? The disconnects per NEC are supposed to cut before the SCC for the panels. I have a 2-pole DC breaker between SCC and battery busbar.
I have the inverter output connected via an extension cord to easily alternate inverters should I choose. If I needed code inspection a DIN breaker might be needed- but the cord feeds a GFCI that feeds a breaker panel 10” away. AIO Inverter has a 150A fuse and the alternate has a ??200A fuse iirc. Plumbed with 2/0

must be able to quickly be disconnected per NEC

there are DC breakers of appropriate design and spec

There are DC breakers of appropriate design (2-pole) and spec (600VDC or 1000VDC)

 

[JCSchwarb]

Yes.

I use fuses at the panels; not a one has ever blown nor do I expect one to blow. But they’re there….

Inside I have 2-pole DC breakers on DIN rail that are essentially disconnects. They are 2A above the panel fuses so other than some bizarre unlikely backfeed event I can’t imagine one them tripping.

??? The disconnects per NEC are supposed to cut before the SCC for the panels. I have a 2-pole DC breaker between SCC and battery busbar.
I have the inverter output connected via an extension cord to easily alternate inverters should I choose. If I needed code inspection a DIN breaker might be needed- but the cord feeds a GFCI that feeds a breaker panel 10” away. AIO Inverter has a 150A fuse and the alternate has a ??200A fuse iirc. Plumbed with 2/0



There are DC breakers of appropriate design (2-pole) and spec (600VDC or 1000VDC)

This video is good to consider on how breakers may not properly shutoff power once a DC arc starts. Having insulated wire cutters close by is a good safety option.

 

[12VoltInstalls]

video is good to consider on how breakers may not properly shutoff power once a DC arc starts

So is that a Chinese wonder or a properly design breaker?
We don’t know.

 

[JCSchwarb]

So is that a Chinese wonder or a properly design breaker?
We don’t know.

Good representative sample. The point is the arc exceeds these CB types causing a meltdown that only stops when the wire gets cut.

 

[12VoltInstalls]

The point is the arc exceeds these CB types

My point is that you can’t say that without knowing what’s inside, how they’re made.
There are appropriately designed DC breakers with sufficient volt ratings for PV

 

[JCSchwarb]

My point is that you can’t say that without knowing what’s inside, how they’re made.
There are appropriately designed DC breakers with sufficient volt ratings for PV

One must understand what DC breaker implies. Is it slow to trip to allow a current inrush? If so, then a cascading affect can occur before the CB trips. That’s why many recommend T fuses over CBs.