Has anyone ever used these din rail manual transfer switches?

[meetyg]

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I'm looking for a transfer switch and found these on amazon, link to the product (not affiliated) .. they are dirt cheap, sell for about $15-$20 and offer a very simple transfer switch mechanism, lift left side up and right side goes down and vice versa. I'm wondering if they can be considered safe if installed with other breakers. Has anyone ever used these types or why not? Any feedback would be appreciated

Yes, I'm using something similar, different branding (TOMZN).
I haven't had the need to switch much, as in my setup it for bypassing the inverter, should I need to do some maintenance or if a fault occurs.

But, as I'm a but paranoid, I use it like this:
1. If I need to manually switch, I turn off one input and only then turn on the other. Yes, it has a mechanical interlock, but I prefer not to trust it much. It should help preventing accidental switching on of two power sources at the same time. But if you are doing this purposely, why not just do it right?

2. I do not trust it as a breaker, just as a transfer switch. So I have separate breakers for over current protection on each input.

Other than those two precautions, I don't see much problems using it (other than the fact that it's Chinese and not UL listed, if that's important to you).

 

[meetyg]

I've used a number of these auto/manual transfer switches recently. They work quite well.

TOP 110V 2P 63A Dual Power Automatic Transfer Switch Generator Changeover Switch | eBay

Specifications: ATS Level: CB level Use Level: AC-33iB Total Size: About 150×137×118mm (1mm=0.0393Inches) Line Voltage: AC110V Line Current: 6A-63A Operating Frequency: 60HZ Insulation Voltage: AC110V Conversion Time: 2S or so Conversion Mode: self cast Display Function: Indicator light display...

www.ebay.com

I also use something like this, but for a special purpose, not exactly as a grid/inverter transfer switch.

I have some critical loads on my inverter output. This includes a small A/C unit. But, I want it to be on only when grid goes down (because my main A/C unit isn't connected to the inverter).
So I'm basically using it to sense if grid is available. If it is, A/C unit is not powered. If it isn't, this ATS will switch to "reserve" powered by inverter socket and A/C unit will turn on.
This is done by wiring only the A/C only to the reserve side output. "Main" output is not connected to anything. Usually, as a real ATS, you need to jumper both outputs to your load.

I wouldn't trust it much as an ATS with two power sources. Not because I have observed any fault in its operation, but because it's cheap and the consequences of having two power sources (grid and inverter output) is fatal to the equipment.

 

[Texican]

I went with a rotary type transfer switch that came with a metal box. have the off grid inverter on one side and the grid feeding the other side going to the load ( a mini split) so I can power the hvac from either source, cost about $125 with the box, so not super cheap. came from a canadian company I think

 

[littleharbor2]

I also use something like this, but for a special purpose, not exactly as a grid/inverter transfer switch.

I have some critical loads on my inverter output. This includes a small A/C unit. But, I want it to be on only when grid goes down (because my main A/C unit isn't connected to the inverter).
So I'm basically using it to sense if grid is available. If it is, A/C unit is not powered. If it isn't, this ATS will switch to "reserve" powered by inverter socket and A/C unit will turn on.
This is done by wiring only the A/C only to the reserve side output. "Main" output is not connected to anything. Usually, as a real ATS, you need to jumper both outputs to your load.

I wouldn't trust it much as an ATS with two power sources. Not because I have observed any fault in its operation, but because it's cheap and the consequences of having two power sources (grid and inverter output) is fatal to the equipment.

I've only used them as a way to switch from Off-Grid power to Genny power on mini split systems.

 

[Hedges]

I bought one of those, Chinese made through eBay. Listing said 63A but I'm not sure I believe it.
It is interlocked; one breaker is on when up, the other on when down, tied together.
I thought it was supposed to provide circuit breaker function, not just switch.

I used it to switch between grid and inverter output. At maybe 40A to 50A, It was buzzing. Not sure if that means magnetic breaker approaching trip current.

I was afraid of it failing deadly and killing my inverters, so replaced with a Square-D QO generator panel (interlocked breakers.) Maybe it was just a lower current rated unit.

It will transfer very fast. With the Square D I can transfer fast, or turn on off and wait any amount of time.

I saw a (German?) brand with similar function, actually a variety of poles which could be ganged. You may be able to pay more for a listed one.

Even if you don't trust the cheap one to not cross grid/inverter, it might be useful to select one of two large loads (e.g. microwave vs. coffee pot, dryer vs. stove) for smaller inverters. If single phase, a 3-way switch would do that too.

 

[ricardocello]

I do not regret installing subpanels with generator interlocks, at least the HOM breakers are UL listed.