MEP-003a and Generac transfer switch

[Roger O]

Hi everyone, I didn't really know where to post this thread, so if it's in the wrong place mods, please move it.

I recently bought a house that had a new Generac 200 amp transfer switch. I would like to connect my MEP-003a to it for automatic load transfer control, but don't have a detailed wiring schematic of the switch. The one in the manual is only a pictorial diagram and doesn't give enough info. I have already made a PLC for the generator, to turn it on when the power is lost, and also fully realize that the generator cannot possibly power a fully loaded 200amp circuit (that's where load shedding comes in).

I spoke to Generac (even pleaded with a supervisor), and because I am not a registered electrical contractor with them, they won't give me the detailed schematic. Has anyone here done this before, and if so, can you tell me how to wire the low voltage wiring?

Thanks for all your help!

 

[Scar59]

I have a 22KW Generac unit and 200 amp transfer switch wired to the house. What color is your transfer switch? Yellow (older) Gray (newer). Ive had both.
Pretty easy to hook up. Ziller Electric in Michigan are great folks (big Generac dealer) Generac.com has all the schematics by model #, don't even have to talk to a person. If the switch is not malfunctioning/shorted, the hook up is easy. Load management will be the trick, you may have to wire it to a aux circuit box.

 

[pclausen]

Is the transfer switch like this one?

That's what I installed at my folks house a few years ago. I'll dig around and see if I still have the installation manual for it. On Generacs, most of the "brains" is inside the generator itself vs. the transfer switch.

You basically got your L1, L2 and N from the utility being feed to the generator to monitor the line from the power company. Then you have DC common and 12VDC to charge the battery, and finally you have "TRANSFER" which sends a signal to the transfer switch, telling it to switch to emergency input. At least that is my understanding. I would imagine "TRANSFER" is pulled to ground to flip the transfer switch to emergency, but I'm not sure, been a long time since I did the install.

 

[Isaac-1]

Do you have the model number of the transfer switch, many residential Generac automatic transfer switches built in the last decade or so are really brain dead switches that rely on the generators controller for all of their logic. Inside is not much more than an electrical contactor and a few wires to let the onboard generator controller sense utility voltage.


Ike

p.s. I would suggest asking for help over on the smokstak board in the Generac subsection of the Generator board

 

[Roger O]

Thanks everyone, sorry for the delay, but I lost my internet for a few days. The transfer switch I have is a new one, model # RTSX200A3. I am comfortable reading electrical schematics and working with high voltage (I am a long time ham radio operator), so all I need is the print, and I'll be ok. As I said, the only problem is that Generac themselves has very poor customer service, and will not help me.

My main objective is to see how the automatic portion of the system works, which will enable me to hook it to the generator.

Roger

 

[DieselAddict]

You could be looking in the wrong place. Try looking in one of the generator manuals such as this one and see if it helps:

http://www.elem.com.pl/app/webroot/files/File/generac/ManualInstalation.pdf

 

[Roger O]

Thank you DieselAddict, that's just what I was looking for. Now I can figure out the connections!

Unfortunately, I did not have a say in what transfer switch they installed, otherwise I would have gone to a much more generic (NOT Generac) "diesel friendly" switch. Depending on it's reliability, I might change what I have anyway.

Does anyone have the name of a manufacturer who makes a good auto transfer switch that works well with the MEP-003a?

Roger

 

[DieselAddict]

If you have your own PLC running the 003 it shouldn't be hard to program an output to handle the Generac transfer switch. I wouldn't go through the effort to replace it if its already installed.

 

[Roger O]

I guess I was just frustrated at the whole Generac deal. I do have a PLC, and will work on the switch asap. Thanks again to everyone, and have a great weekend!

Roger

 

[SteveH]

Hi Roger,

I have an Emerson Network Power transfer switch which works perfectly with my PLC controlled MEP003. It doesn't do load shedding though. I did find a small company that manufactures generic, intelligent loads hedders but in the end determined I didn't need it (advice from electrician). I'm away from home at the moment but can get you more details if you are interested later in the week.

-Steve

 

[Roger O]

Thanks Steve, any and all info is greatly appreciated!

Roger

 

[SteveH]

Hi Roger,

Sorry for the delay in getting back to you. I'm using an ASCO 185 transfer switch with my MEP003a and PLC autostart. Been working great for about a year (and we've had about 3 or 4 power outages in that time). I just used the closed contacts from the ASCO to let the PLC that it was time to start. From the contacts closing to power up and running is just under a minute (prime, preheat etc). I'm lucky - my MEP003a normally starts first time, though I have the PLC set up to give it three attempts

-Steve

 

[Roger O]

Thanks for the reply Steve, I will look getting the ASCO 185.

 

[reset2]

Hi everyone, I didn't really know where to post this thread, so if it's in the wrong place mods, please move it.

I recently bought a house that had a new Generac 200 amp transfer switch. I would like to connect my MEP-003a to it for automatic load transfer control, but don't have a detailed wiring schematic of the switch. The one in the manual is only a pictorial diagram and doesn't give enough info. I have already made a PLC for the generator, to turn it on when the power is lost, and also fully realize that the generator cannot possibly power a fully loaded 200amp circuit (that's where load shedding comes in).

I spoke to Generac (even pleaded with a supervisor), and because I am not a registered electrical contractor with them, they won't give me the detailed schematic. Has anyone here done this before, and if so, can you tell me how to wire the low voltage wiring?

Thanks for all your help!

An chance of posting pictures on your setup?

 

[SteveH]

An chance of posting pictures on your setup?

RogerO:

Unfortunately I think the Generac transfer switches are pretty brain dead, unless they are connected to a generac generator (they have some kind of communication link to the generator, which is where the decisions are made. This would make it tough to interface to the Mep, but if somehow has the diagrams we might be be able to work it out...

 

[Roger O]

Thanks Steve, The transfer switch has a 220v terminal that connects to the generator, I believe that is the "sense" circuit. i.e, when the plc on the generator doesn't see 220 volts it knows the line it down, then starts the engine. When the engine is producing power, it energizes the 220v relay at the transfer switch which trips the switch to transfer the load to the generator. What I don't know is what happens when the line power comes back on. I'm thinking that the 220v sense circuit is now re-energized which tells the plc to stop the generator and remove the 220v from the relay. Thoughts?