pv dc disconnect

chrisw5

New Member
Quick question here: I'm getting my solar ready to install and was wondering about dc disconnects. I will have two different arrays installed on the roof. 1 string of 8 in series of 305W panels (Voc of 40V) and another string of 6 in series 305W panels (also each at Voc of 40V). I have a Sol-Ark 5k inverter with 2 solar panel inputs (MPPT1 and MPPT2). Solar Panel String 1 will feed MPPT1. String 2 will feed MPPT 2.

The closest direct path to my inverter in the garage will be through the roof. I will be using a Soladeck enclosure to feed the dc wire through the roof into a flexible metal conduit that will terminate into a metal wireway to feed into the Sol-Ark.

From what I have gathered, since I'm not paralleling any panels, no combiner box is needed, nor fusing. The Sol-Ark has a pv dc disconnect integrated into the unit. Do I need a pv dc disconnect between the inverter and the panels? If so, is there harm in putting a dc disconnect inside in the garage? I have seen some examples mainly in Australia where they require DC isolators where these types of disconnects have failed or caught fire due to shorts due to water penetration of the enclosure.

My locality does not require rapid shutdown, and I'm not planning on installing any automatic rapid shutdown device.

I already have an IMO dc disconnect, so I'm not sure if there would be benefit to installing it or not. With the amount of voltage in my system, I'm a little leery of any additional contact point that could pose a potential failure point. Thoughts?
 

OffGridInTheCity

Solar Addict
If you have a way to disconnect the incoming PV at the SolArk - then that's all you need. The main points of 'disconnects' are
1) Code / quick disconnect outside - doesn't apply to you per your comments
2) Multiple combined strings case - its nice to be able to turn on/off each string for diagnosis at the combiner - you can do this at the SolArk? - e.g. you have a breaker for each string?
3) A local breaker at the main power panel (inside typically) to disconnect PV power for safetly when working on things.

If you can disconnect each string at the SolArk - then it sounds like you have it covered :)
 

chrisw5

New Member
Thanks! It appears the Sol-Ark’s pv dc disconnect only isolates the inverter from the pv inputs, so if I needed to move, isolate, or reconfigure mppt inputs this could not be done safely without an additional dc disconnect between panels and inverter, yes?
 

OffGridInTheCity

Solar Addict
Thanks! It appears the Sol-Ark’s pv dc disconnect only isolates the inverter from the pv inputs, so if I needed to move, isolate, or reconfigure mppt inputs this could not be done safely without an additional dc disconnect between panels and inverter, yes?
Sounds correct and to help with communication, let me provide a visual. I could be misunderstanding and this is up to you in any case :)

In my system I have 3 set's of 15 panels. Each set is combined outside to a pare of wires carrying 100v@45a routed inside to it's respective charge controller. But just before they they go into the charge controller (SolArk in your case) I have a circuit breaker on each set so I can shut off the incoming power - either an individual array or all of them. Here's a pic of the 3 circuit breakers (1 for each array) and the 3 Midnite Classic 150 Charge Controllers.
1632494067563.png
I'm suggesting that you should have 2 circuit breakers - 1 for each string - before they enter the SolArk.
 
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