You CANNOT use this generator to power a 120/240v service. It is either 120v or 240v. NOT both, which is required to use with a house panel and transfer switch with an L14-30P.

Thanks Petey Racer for the response. Isn't it the work of the transfer switch and how it's wired to deliver either 120v / 240v to the appropriate circuits? and not to the entire panel and all it's circuits.? All the transfer switch panels seem to come with that 4 prong "twist lock" receptical. What am I missing here? thanks again

The transfer switch does not change the voltage. What is the nameplate voltage on that generator? That is all that available from that generator, period.

The generator output will require alteration to connect to 120/240 V, if it is even capable (some are).

There is no "NO adapter to make a cord set work between the 2 different outlets" since you do not have the required neutral for a 120 V load available.

So, in the end what can I do with my 5000W generator that has both (2) 120v/20A...(2) and (2) 240v 20A outlets to get a transfer switch to work in my case when and if power goes out? I want to be able to power up "essential" circuits for furnace, fridge, and kitchen outlets if possible. This is becomming very complicated for me...thanks

I believe that the two 120 volt outlets will provide the desired 120/240. But that needs to be verified. Until this post, needed information was scarce. Don't be stingy with details when asking for advice. Can you post the make and model or a website that has the technical information about your generator?

http://yodermachinery.net/54447/ (link to make and model)

I hope the additional info as to make and model will help some..........thank you.

That is a Devilbiss clone unit. It was sold under several names.
Linked is the wiring diagram. If you had to, you could replace the 120v receptacle, or add a new one with an L14-20R.
Or you could home make and adapter cable that plugs into both halves and leads to an external L14-20R.

The 120v receptacle IS actually split into two separate circuits.

Here is a link that might be useful:

If you have 120 V receptacles you would need to measure between the 120 V hots and make sure you have 240 V.

Then you could make a Y cord to use the 120 V receptacles AND their neutrals to feed 120/240 V into a transfer switch.

The neutrals are connected together on the generator side, and each hot feeds one leg of the 240 V input.

thanks for all the suggestions / answers to my problem. We'll have to try that now....

It sounds like it has a 240 V output from the actual windings with a center tape to make a pair of 120 V outputs (a pretty normal setup).

Make sure there is not voltage between the two neutral on the 120 V outputs (or at most a very small voltage) before connecting them together.

You may need to load down both 120 V outputs to get a good measurement.
A 100 W light bulb should be more than adequate on each output.