Generator Prep / Transfer Switch

[Rotnjonny]

I have a 2022 Montana 3791RD with Legacy Package. It has the factory generator prep package. I want to wire an additional 50 amp input box up front for when I want to use my portable generator. I have located the box that has the terminated ends for the generator installation in the front basement (wired to transfer switch I would assume) I have a green and ground tied together. I have a red terminated and a black terminated. All this makes sense. BUT I also have a solid blue and a solid white tied together. These two I am unfamiliar with. What is the purpose of the blue and white? Is that part of the stop/ start for an onboard unit?

I used the search feature but didn’t find a diagram. Any assistance would be greatly appreciated

Thank you

[rohrmann]

Red and black are the two hotlegs. Green is the ground, but where is the other wire you are calling a ground? There will only be one ground, one neutral, normally white, which is a current carrying conductor along with the two hot legs.

[Rotnjonny]

In the picture, you will see a green ground, with an earth ground/neutral (copper uninsulated). There is a black and a red. Those are the hot legs. There is a solid white with a solid blue attached. That is the pair that I haven’t seen before.

[Daryles]

Here's a picture inside a transfer switch (not mine).
It shows a bue and white wire together in one of the terminals.

[Foldbak]

See the attached pictures. The romex comes from the TS. Follow those colors.

[Rotnjonny]

Originally Posted by Daryles

Here's a picture inside a transfer switch (not mine).
It shows a bue and white wire together in one of the terminals.

Thank you. That confirms where they are using it on the transfer switch. I personally haven’t seen a blue/white used like this.

[Mark7]

The blue wire is (correctly) identified with white tape meaning someone wanted future "electricians" to know it was not a mistake. When using any color other than white (gray for 277/480) for a neutral it needs to be identified as such.

Same goes for using a white wire as a "hot" leg. It used to be done all the time for switch legs, but it needed to be identified, usually with a wrap of black tape to ID it as a line voltage wire.

Would be curious what the other end of that blue/white wire is hooked to though... Seems funny a manufacturer would not just use a white wire.

edit: Looking again it looks like that blue wire is part of a wrapped cabe (Romex) or a drop cord some sort. Is there also a bare ground wire present in that cable? I don't think I have ever seen a 10-4 WG cable for 120VAC wiring unless it is 3PH. Then Red, Black, Blue and White would make sense. Interesting!

[Rotnjonny]

I am glad I am not alone in finding this situation as interesting. 😊

I have not traced the wiring back to the transfer switch yet, so I haven’t seen the other end. One of the other members posted a picture of the transfer switch that is contained in the thread.

I do not claim to be a professional electrician, but I have done my fair share of electrical work as a home owner and RV owner. It strikes me as odd that there are six lines present. The black and red are capped. Those are the hot legs for sure. The solid copper and green are capped together, which I would have believed to be ground/neutral. The white and blue are capped together. The blue has the white wrapping as you identified. Thats what I found as “curious ”.

I suspect once I trace the lines back to the transfer switch, it will be much more clear.

[Lee-CI]

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