Return to the Electrical Wiring Forum | Post a Follow-Up

 o
Generator connection problem

Posted by orest402 (My Page) on
Tue, Jan 24, 12 at 23:04

My question concerns my portable generator and how to make a connection between it and the house (transfer switch). My generator has 2/ 220V outlets (20A).3 blade type with one horizontal and one vertical blade and one grd. pin. The transfer switch has an inlet box with the 4 prong (twist lock/ L14-30 male plug. Thre is NO adapter to make a cord set work between the 2 different outlets. What do I do to make this project work? Some generators have the L14-30 already on the generator...don't know why this one doesn't. Thanks for any input...


Follow-Up Postings:

 o
RE: Generator connection problem

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.


 o
RE: Generator connection problem

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


 o
RE: Generator connection problem

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.


 o
RE: Generator connection problem

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.


 o
RE: Generator connection problem

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


 o
RE: Generator connection problem

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?


 o
RE: Generator connection problem

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

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


 o
RE: Generator connection problem

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: Diagram


 o
RE: Generator connection problem

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.


 o
RE: Generator connection problem

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


 o
RE: Generator connection problem

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.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Electrical Wiring Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here