Automatic Transfer Switch Install

[pteck]

Got around to installing an automatic transfer switch so I can power all my 120V receptacles from an alternate power source.

There's several varieties of them on the market but I used a Progressive Dynamics PD5110610V 50amp

It basically detects power input from one of 2 sources. Automatically choosing an actively powered source to relay into the panel. If two sources are active, it will default to one leg (labeled generator). It also has a 30-45 second timer when it detect power on the generator leg to switch to but I disabled this time (bridging a solder joint per instructions).

I'm using this to switch between a 2000W inverter and shore power.

Though it really could be used for two power sources like generator, inverter, shore power, portable battery power station. Or joined in series to enable switching between more 120V sources. No worries about accidentally joining two hot sources.

I installed it behind the power center of my 27FB, which has just enough room. The 30amp/10gauge wire is pretty stiff to work with.

Works great and transparently!

Here's what it looks like:

[Shinytow]

Originally Posted by pteck

Got around to installing an automatic transfer switch so I can power all my 120V receptacles from an alternate power source.



There's several varieties of them on the market but I used a Progressive Dynamics PD5110610V 50amp



It basically detects power input from one of 2 sources. Automatically choosing an actively powered source to relay into the panel. If two sources are active, it will default to one leg (labeled generator). It also has a 30-45 second timer when it detect power on the generator leg to switch to but I disabled this time (bridging a solder joint per instructions).



I'm using this to switch between a 2000W inverter and shore power.



Though it really could be used for two power sources like generator, inverter, shore power, portable battery power station. Or joined in series to enable switching between more 120V sources. No worries about accidentally joining two hot sources.



I installed it behind the power center of my 27FB, which has just enough room. The 30amp/10gauge wire is pretty stiff to work with.



Works great and transparently!



Here's what it looks like:

Attachment 341669

Attachment 341670

I really can’t see how this has been installed from the photos. Can you explain/show your installation in more detail?

[pteck]

Originally Posted by Shinytow

I really can’t see how this has been installed from the photos. Can you explain/show your installation in more detail?

Happy to. I don't have more pics as it's all closed up, but can explain. I'll assume a 30amp trailer install.

A 120V automatic transfer switch has 3 thing going to it:
1) Input source A (default)
2) Input source B
3) Output

It automatically switches to whatever input source is powered. If both A and B are powered, it defaults to A.

Input A is the 30amp trailer power input.
Input B is my GZ

The way to install this is to locate the trailer input wire (big orange 10 gauge romex). The power center will be fed by this big orange wire at its backside.

Idea is to cut said big orange wire. The feed side goes to input A of the transfer switch. The other end of the wire that goes to the power center will install to the output side of the transfer switch.

Note that this 10/3 gauge wire is super stiff and hard to work with. You may also not have enough slack in the line and have to add another segment. I removed the original line from the power center, fed to auto transfer switch. Then added a new ~3' segment of 10 gauge romex for the auto transfer switch output to power center.

Now get an extension cord or suitable wire, to install to input A of the transfer swtich. This will now plug into your new GZ (or any other 120V source like an inverter or genny).

One more detail. The specific transfer switch I used has a 30 second delay timer meant for generators such that it can stabilize its output before it switches. The manual tells you how to disable this by jumping points on a circuit board which I did.

[pteck]

This video may help to better conceptualize how a transfer switch is installed

https://www.youtube.com/watch?v=jpICwTtAV_I

[GOUSC]

Thanks for the video's as they do explain how everything has to go together. I'm trying the determine if I will be able, (or have someone else), install an automatic transfer switch, ATS, in my 2018 Globetrotter 27FB Twin. I have a Post of where I plan to run power for a cigarette lighter outlet to charge my Yeti GZ 1000. I'm pretty sure it will be my first option noted in this post;

https://www.airforums.com/forums/f54...er-208454.html

If I recall correctly, in your set up you have room for your Yeti GZ 1000 in a space just adjacent to your AC / DC distribution panel and room behind that panel for your ATS.

There is no such room in the GT in that location. I barely had enough room to remove the stock converter and replace it with a boondocker converter.

The only place it could possibly work be under the couch which is adjacent to the AC/DC distribution panel under the refrig. I'll have to check and see if the Yeti will even fit there and then decide if I'm willing sacrifice that storage space. If I decide to use that space then it would be a shorter area to pull power for the cigarette lighter to charge the GZ than where I currently plan to use.

Anyway, thanks for the video as it at least illustrates what I have to work with.

[brogo]

Howdy! First, I just want to say thanks for all of the useful info you've posted in these forums–it's been a huge help to me as a novice Airstreamer.

I have a 2005 Bambi 19CB and plan to do the same thing you did with your Goal Zero Yeti. I noticed you mentioned you installed a Progressive Dynamics 50amp Transfer Switch, but the link sent me to a 30amp version on Amazon. My trailer has a 55amp Progressive Dynamics lithium replacement converter already installed for my house batteries—is this the ATS I'll need?

https://www.amazon.com/gp/product/B0...KIKX0DER&psc=1

If not, do you have any recommendations?

Thanks!

[GOUSC]

I determined that I don’t have the expertise to install a transfer switch and have gotten by without it. Pteck is the person to reach out to with your question. I think he has the 30A transfer switch so that’s probably why the link sent you to a 30A. My initial guess is what you are looking at is not the switch. The 240V in the description concerns me.

[kscherzi]

Pretty interesting product. As I see it the device takes the normal pedestal shore supplied 120 volt shore power and directs it into the trailers onboard power converter unless an alternate 120 volt power source is detected (generator, inverter, etc) then switches to that source to be directed into the onboard power converter. Not that complicated. I have a similar trailer. The only hard part I see is routing the inverter AC output from the front storage area (where the batteries and inverter are) to the converter location.

A few questions:

1. When on inverter power how does this system prevent inverter power from reaching the battery charging system of the converter, all the while allowing shore to do so? Charging the batteries from power taken from the batteries is nonsensical.

2. My trailer has a propane refrigerator that automatically switches to AC 120 volt if that source is available. Operating the refrigerator off the inverter 120 volt output is undesirable as it will accelerate battery discharge. I guess I could remember to manually switch the fridge to propane, but the potential for forgetting is high. Do you have another automatic way? The same question applies to the propane / electric water heater.

3. Obviously a 2000 watt inverter is an inadequate power source for the air conditioner, and most folks don't have the numbers of batteries needed anyway. If tried I suppose the inverter will eventually overload and shut down or the air conditioner will somehow abort compressor startup. Regardless, probably bad for the overall system. Do you have a lockout, or just hope the thermostat isn't still set to run the air conditioner from the last campground?

Thanks for sharing the idea. Will Prowse is quite the curious and informative fellow.

[SandKSmith]

Originally Posted by kscherzi

Pretty interesting product. As I see it the device takes the normal pedestal shore supplied 120 volt shore power and directs it into the trailers onboard power converter unless an alternate 120 volt power source is detected (generator, inverter, etc) then switches to that source to be directed into the onboard power converter. Not that complicated. I have a similar trailer. The only hard part I see is routing the inverter AC output from the front storage area (where the batteries and inverter are) to the converter location.

A few questions:

1. When on inverter power how does this system prevent inverter power from reaching the battery charging system of the converter, all the while allowing shore to do so? Charging the batteries from power taken from the batteries is nonsensical.

2. My trailer has a propane refrigerator that automatically switches to AC 120 volt if that source is available. Operating the refrigerator off the inverter 120 volt output is undesirable as it will accelerate battery discharge. I guess I could remember to manually switch the fridge to propane, but the potential for forgetting is high. Do you have another automatic way? The same question applies to the propane / electric water heater.

3. Obviously a 2000 watt inverter is an inadequate power source for the air conditioner, and most folks don't have the numbers of batteries needed anyway. If tried I suppose the inverter will eventually overload and shut down or the air conditioner will somehow abort compressor startup. Regardless, probably bad for the overall system. Do you have a lockout, or just hope the thermostat isn't still set to run the air conditioner from the last campground?

Thanks for sharing the idea. Will Prowse is quite the curious and informative fellow.

All good questions. I did this same installation a couple of years ago, and yes, I've inadvertently powered both my battery charger and refrigerator with my GZ 1400 as you suggest might happen. The solution is to add a switch to the wire that charges the batteries at the charger so you can turn the charger off when powering the trailer with the inverter. Could that be done automatically? Sure: add a relay in the circuit that held closed when on shore power, and opens when shore power is not there.

All that gets complicated. Adding the switch is straightforward, but a check list addresses those items that have to be remembered like the charger, water heater, fridge and ac unit. After a while it becomes another camp setup item that is quickly and easily accomplished.

I'm very pleased with the transfer switch. One side of the transfer switch has a timing feature that allows generators to settle out before completing the transfer. Wire that to the shore power side, and the inverter to the other. You just have to remember to wait a minute after connecting the shore power before checking to see if the power is indeed connected. It won't be instantaneous I usually do that by noting that the fridge has changed from gas to AC power.

The rats nest wiring shown in the photos is much like what I found. Unless cleaned up a bit, it can make it difficult to reinstall the converter/charger when the transfer switch is located behind it.
Steve

[pjshier]

Our 2017 Int'l Serenity 27 FBT came with two shore power/generator connections in the outside of the coach - one in the front and one on the side near all the other hookups, and the input source was governed by an automatic selector buried behind the power controller. When I replaced the power controller with a new Boondocker in advance of the lithium upgrade, I ended up removing the automatic transfer switch as it complicated the conversion slightly and we almost never use the side-located power input for this 30A coach.

Thinking now I might retrieve the auto switch from the shed and reinstall as a safety measure if we start using other power (portable Lithium) bricks...

[PB_NB]

I installed a GoPower transfer switch in the 22FB. Along with our solar and lithium solution. Main reason for installing mine was to provide power to all the 120V AC outlets regardless of the power source. Mine switches between my inverter and shore power (or any other power source plugged into the power plug on the outside of the trailer).

You have to make sure that you wire the converter on the shore power side of the switch so you don't create a loop where your inverter is powering your convertor. This would probably work but your batteries would be working harder to do that.

We use our trailer more off-grid and rely on solar and batteries to power our stuff.

[Wazbro]

Originally Posted by brogo

Howdy! First, I just want to say thanks for all of the useful info you've posted in these forums–it's been a huge help to me as a novice Airstreamer.

I have a 2005 Bambi 19CB and plan to do the same thing you did with your Goal Zero Yeti. I noticed you mentioned you installed a Progressive Dynamics 50amp Transfer Switch, but the link sent me to a 30amp version on Amazon. My trailer has a 55amp Progressive Dynamics lithium replacement converter already installed for my house batteries—is this the ATS I'll need?

https://www.amazon.com/gp/product/B0...KIKX0DER&psc=1

If not, do you have any recommendations?

Thanks!

Welcome to the forum.

Unless someone paid to convert your 19CB to 50 amp service it is still 30 amp as it came from the factory, so no. The 55 amp 12 volt output of your converter has nothing to do with AC coming into your trailer. So you probably need a 30 amp transfer switch. Count the number of prongs on your shore-power plug, 3=30amp, 4=50amp.

[brogo]

Originally Posted by Wazbro

Welcome to the forum.

Unless someone paid to convert your 19CB to 50 amp service it is still 30 amp as it came from the factory, so no. The 55 amp 12 volt output of your converter has nothing to do with AC coming into your trailer. So you probably need a 30 amp transfer switch. Count the number of prongs on your shore-power plug, 3=30amp, 4=50amp.

Perfect, thank you!

[pteck]

Thanks to everyone here having done a great job answering questions and I agree with them.

The link in the original post somehow has a 50amp misnomer, but it is indeed a 120V 30amp switch that you're looking for. Boy, have they gone up in price.

Here's a couple more units that would fit the bill:
- https://www.amazon.com/PowerMax-PMTS.../dp/B006FLT0IG
- https://www.amazon.com/Surge-Guard-4.../dp/B073PD854Q

[TrvlngTinTin]

http://APIELE Changeover Selector Sw...a.co/d/aSKoMbl
This is another alternative. One Nice thing with this is. No contact points to consider. Or worry about?
I have installed one of these and it worked fine.
Make sure you get right size.