diy solar

diy solar

DIY Transfer switch


The company, Enphase, makes PV microinverters a number of people here use. Also battery/inverter units.
This product is transfer switch and auto-transformer. It has some electronics to monitor grid voltage/frequency and decide when to disconnect.

It appears to require Enphase Enpower an IQ Envoy according to instructions. Obviously easiest to use a company's supported equipment together, but possibly the transfer switch could work with other equipment.
Probably their Encharge can connect in parallel with the grid for peak shaving and the like in addition to battery backup with grid disconnected. Unlike generator input which would only connect when grid disconnected. So communication between their products supports this.

 
I am running 2 of these on my solar system. They work really well.Connecticut Electric EGS107501G2KIT EmerGen EGS107501G2 Manual Transfer Switch Kit 30 Amp, 10-Circuit, 7500 Watts, For Portable Generator https://www.amazon.com/dp/B005FQJD7...t_i_00A03M1SH38YBSQYYHTV?_encoding=UTF8&psc=1
appears at a glance to be a clone of the pro-tran by Reliance (clone isn't meant to be negative, merely a comment on the similarity [God what have we come to that feel the need to clarify this]) and thus would share the same strengths and weaknesses. If it switches neutral however, then it is in a whole new league and I might need to grab one.
 
What can be so important in a house that can not be off for a few minutes? If using inverter as backup, nothing stays on when main grid goes down.
Every disconnect I have encountered have a center position where both supplies are disconnected. Must be a reason.
But these manual switches are recommended. https://www.bluesea.com/products/category/7/38/Switches/Rotary_Switches
May I suggest this company, fraction of the price of the blue sea. Configure just how you want it. https://www.c3controls.com/products/cam-switches/
 
This one is fast enough, because turning one breaker on trips the other off:

This is the one an electrician installed for my outside portable gnererator. Mine has a 60A double pole breaker installed. Works great butt limited circuit slots. Had to use tandem breakers to get the coverage I needed.
 
This is the one an electrician installed for my outside portable gnererator. Mine has a 60A double pole breaker installed. Works great butt limited circuit slots. Had to use tandem breakers to get the coverage I needed.

Mine came with 100A and 30A breakers interlocked, 30A wired to the recessed generator plug.
I replaced both breakers with 70A for my application. Either 70A from grid or 70A from battery inverters (which act as UPS) feed the busbars, and lugs connect 6 awg run to the house. There, another panel has all the circuits I need.

Purpose is a manual bypass to take inverters out of the circuit.
I previously used a cheap DIN rail transfer switch rated 63A, from a Chinese vendor on eBay. But it made strange buzzing sounds that concerned me, might fail in a bad way. I've seen similar products available from reputable brands. It is very important to me that the two sources never get connected in parallel, even a moment of arcing. That would feed grid to the output of my inverters.

Elsewhere I use interlock kits between main breaker and backfed breaker. That has a more deliberate slow switching with off time between them. For some applications (moving a grid interactive inverter from one source to another), need to have 5 seconds off to ensure inverter drops offline before an out of phase source is connected.
 
I use this automatic transfer switch:


It switches in 30mS and while I can detect the LED lights flicker when the switchover occurs, none of my electronics, computers, etc have any issues with it. No reboots, resets, or clock issues.

I do have a whole house surge suppressor installed just in case, though, so that might be handling some of the spikes that would be expected from this type of switchover.

Note that it is not sealed, and in fact throws sparks out the vents when it switches, so you want to be very deliberate with your installation choices.

So far I've been using it for months, and have switched it hundreds of times, under load, without issue.

I do not have the wifi switch included connected.

It does have a manual mode.
 
Note that it is not sealed, and in fact throws sparks out the vents when it switches, so you want to be very deliberate with your installation choices.


?

I see it is DIN rail. Having that inside a metal box could help. But looks like those vents are exposed through any bezel, along with the lever. So want a metal door over the front.

Sometimes electrical panels go in a closet. That closet is NOT supposed to be used for clothing, because breakers when they trip can throw a flame.

Definitely not something for the bilge of a boat, or other places where "explosion proof" is required.
 
Your last sentence makes no sense to me. The first phrase is correct but the second phrase has me confused.
Yes the impact of toggle switching is the same but the functionality enabled in each case can be quite different.

What I'm saying with the first phrase is the grid power supply is passing through the AIO, and the AIO is managing the switching between grid power and inverter power (battery/solar). This UPS switching feature is really neat (works well on my PIP).

This is in contrast to the second situation where the output of the AIO is connected to a transfer switch, in the same manner you would connect the output of a backup generator to a transfer switch via a plug in power inlet (or hardwired).

There are reasons why you might want/prefer the latter than the former, e.g. where the AIO does not have the power output capacity to manage all the day to day power demands but is sufficient for supplying power to essential services during grid outages.
 
It like to make or maybe purchase a transfer switch so I can, obviously, manually quickly switch between solar (inverter) and grid and not have to shut down the appliance or device that's being used. I figure if I flip the switch fast enough there wont be any loss of power to the device.

For the moment I don't want to purchase the MOES switch but you can try and talk me out of it. Too many gadgets.

Thanks

Peter
I have a grid/solar transfer relay & it works lightning fast but here's the problem... When you switch, the sine wave sometimes will be 180 degrees out of phase. This will lock up fridge, freezer & a/c compressors. I bought a device that was suppose to deal with that & shut down for 3 minutes while the compressors balance out but the switching is so fast it doesn't detect it so you have to do 1 of 2 things. Either shut down all compressored appliances before the switch or if your system is like mine, I have an timed scheduled auto switch between solar/grid & visa versa & I have timers on all my compressors to shut down just before the switch & then back on in about 4 mins. If I have to do a manual switch, then I manually shut them all down, just don't forget to turn 'em back on after 4 mins.
 
but here's the problem... When you switch, the sine wave sometimes will be 180 degrees out of phase. This will lock up fridge, freezer & a/c compressors.

Does it? Seems hard to believe one line cycle of wrong phase could stop spinning mass of a motor. I would have thought just a hiccup, maybe slow slightly and catch hold when in phase.
 
Does it? Seems hard to believe one line cycle of wrong phase could stop spinning mass of a motor. I would have thought just a hiccup, maybe slow slightly and catch hold when in phase.
No, a running compressor has too much pressure on the high side, if it gets hit with a 180 degree out of phase waveform, it'll lock it up, I've witnessed it plenty of times but if you make a switch that's in sync, it'll keep running just fine.
 
Thanks for the warning. My manual switch that can be done fast feeds the house, doesn't have GT inverters downstream of it (which wouldn't like reverse phase), so I might have used it that way. Don't want to cause trouble with my refrigerators, though. Guess that means dead time long enough for their pressure to drop.


My battery inverter should be in phase when it picks up after grid failure, just allows a cycle of dropout.

Oh, some to think of it, up to me to just have inverter in phase with grid, it's a 50/50 choice in hooking up wiring and easy to check with DMM. My use of the switch would be to put house direct to grid while I work on inverter. So long as inverter is "on-grid", then I can throw the switch fast.
 
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