Should I install a transfer switch

[keeperofthecode]

My understanding is the EG4 6000xp cannot back feed to the grid but for safety reasons should I install some kind of automatic transfer switch anyways on the grid connections going into inverters? I'm installing a system exactly like Will's video with 2 - EG4 6000 XP inverters feeding a critical loads subpanel. If yes what kind of transfer switch would you recommend?

Will's Video

 

[hwy17]

I'm not sure where exactly you are picturing a transfer switch. Hybrid inverters have internal contactors to switch between passthrough modes.

I would personally install an interlock on the CLP with a separate feed direct from the grid main panel, so that the CLP can be manually failed over back to the grid if the inverter dies or while it's offline for troubleshooting and maintenance.

Basically, install the CLP like a regular subpanel from the main, with a main breaker on the CLP, then install a generator interlock kit on the CLP with a "generator" backfeed breaker. Then the inverter takes it's input from a load breaker on the main panel, and feeds it's output into the "generator" breaker of the CLP. Interlock should be cheaper than transfer switch, just make sure to buy a main breaker panel for the CLP.

You are allowed to buy say, a 100 amp main breaker panel and use that as your CLP, even if the feed from main panel to CLP is only say 60 amps. A 60 amp load breaker on the main panel will serve as OCP, and the 100 amp main breaker in the CLP will just serve as an interlock disconnect.

 

[DIYrich]

Don't need "automatic". Manual transfer switch, or interlock will suffice. More for maintenance. You can take the inverter out of the circuit with the transfer switch and still power your loads from the grid.

 

[Zwy]

My understanding is the EG4 6000xp cannot back feed to the grid but for safety reasons should I install some kind of automatic transfer switch anyways on the grid connections going into inverters? I'm installing a system exactly like Will's video with 2 - EG4 6000 XP inverters feeding a critical loads subpanel. If yes what kind of transfer switch would you recommend?

Will's Video

No need for automatic, one can use a manual double throw switch. This allows bypass of PV system for maintenance or repairs yet still power the structure.

 

[keeperofthecode]

Thanks for the feedback. Anyone want to recommend a double throw switch? I like the idea of being able to keep things going while I work on system.

 

[RCinFLA]

When you disconnect AC input to a hybrid inverter you must allow the inverter's pass-through relay to release before reapplying AC input.

When you open AC input breaker it can take a few seconds to upwards of a minute for inverter to realize AC input has gone open circuit. There will be inverter AC voltage on the open AC input terminals of the inverter until pass-through relay releases that may not be in-phase with a newly applied AC input.

 

[Zwy]

Thanks for the feedback. Anyone want to recommend a double throw switch? I like the idea of being able to keep things going while I work on system.

One like this 100A works for most applications but you can get a 200A also. https://www.homedepot.com/p/GE-100-...ency-Power-Transfer-Switch-TC10323R/100171587 I use a 3 pole Eaton as I run with a switched neutral due to N-G bonding in one inverter. You should not need a 3 pole as your inverter should be a common neutral setup.