Generator

[matt151617]

I'm looking to wire up my generator to the house wiring. This generator only puts out 120 volts and has 30 amps max. It has a NEMA L5-30R twist-lock, a NEMA TT-30R twist-lock, and 2 NEMA 5-20R receptacles. The transfer switch kits I've seen all have 4-prong twist-locks. So I'd have to buy a TT-30R cord, a receptacle, and the transfer switch... that would cost more than the generator.

The other option would be a interlock kit, TT-30R cord, and receptacle. Could I split the 120 inlet onto a double breaker so it'll provide power to both sides of the panel? I do not plan on running any 220v appliances.

 

[HOTFR8]

Another option would be to run a caravan power inlet on the outside of the building and have a dedicated power point that runs off the gen set as I have done. In the photo below you can see the power inlet and inside behind that is a dedicated power point to use power from the gen set once it it plugged in.

This way you do not have to do anything to your wiring. You have no switches to change over and nothing that effects your existing wiring system.

 

[matt151617]

That is a good idea, but I might as well use extension cords if going that route. I'd like to wire up to the lighting circuits and furnace especially.

 

[pattenp]

I have a 8000W geny and put in a 30A inlet and used an interlock on the main breaker. I just flip on the breakers of circuits I want to power. It was a cheap manual solution. We hardly ever lose power so being manual is not a big deal to me.

 

[matt151617]

That seems like the best way, but can I split the 120 from the generator onto a double breaker so it powers both sides of the panel?

 

[pattenp]

That seems like the best way, but can I split the 120 from the generator onto a double breaker so it powers both sides of the panel?

My first thought is it would work to power up both sides of the panel with 120V by splitting the 120V output of the gen. You obviously won't get 240V doing it.

 

[HOTFR8]

That is a good idea, but I might as well use extension cords if going that route. I'd like to wire up to the lighting circuits and furnace especially.

Well I am on Solar power so my system is only to back up the basics. My Invertor automatically cuts off from the grid if the mains power fails and I then run on Solar or battery depending on the time of day. Some of the other options given may be better for you.

One suggestion is that what ever you do have it done by some one qualified that knows what they are doing.

 

[matt151617]

My first thought is it would work to power up both sides of the panel with 120V by splitting the 120V output of the gen. You obviously won't get 240V doing it.

Right, but is it safe/ok to do? I'm thinking install an interlock on the panel. 30 amp dual breaker, both hots tied into 1. Run these in conduit to an outlet. TT-30R cord will connect between the generator and the outlet.

Should I also install a ground rod where the generator will sit? This particular generator has the ground and neutral seperated.

 

[eljefino]

Yes you can run 120 on both legs. There will be zero potential between them instead of 240 so to your stove and dryer it will be "dark".

The only way it would be unsafe is if your generator feed is not completely isolated from the po-co via appropriate switchgear, which would also be illegal.

 

[bd8134]

Hi Matt, I used what you are proposing. It is safe and approved and inspected by my town.
You might be best to check your state allows interlocks, some do not I believe.
I have a panel interlock, a 30A dual breaker, to a 30A power inlet box (male connector pins L5-30), I use a L5-30 lead with a male and female connector.
I do not have an earth spike at my generator, I dont think you need it.

 

[Highbeam]

Sharing the 120 over both sides of the panel is possible but there is one problem. The 30 amp generator breaker is fed by a 10/3 cable. This is because each 10 gauge hot can pass 30 amps for a total of 60 amps of 110 power. There is also a neutral conductor that is 10 gauge that can only pass 30 amps. Well now, this works in a 220 setup because the two hots are out of phase and the neutral will only ever see a 30 amp max imbalance.

Now if you go and try and feed 60 amps of 110 power the way you describe which is all in phase then your neutral is overloaded at 200%.

So, is your genset capable of making more than 30 amps of 110? If not, then you can safely feed both sides of the 30 amp breaker with 10/3 cable.

A nice benefit of this strategy is that your 30 amp 110 volt genset will be able to deliver all 30 amps to any 110 circuit or "side" of the panel.

 

[wyliesdiesels]

Sharing the 120 over both sides of the panel is possible but there is one problem. The 30 amp generator breaker is fed by a 10/3 cable. This is because each 10 gauge hot can pass 30 amps for a total of 60 amps of 110 power. There is also a neutral conductor that is 10 gauge that can only pass 30 amps. Well now, this works in a 220 setup because the two hots are out of phase and the neutral will only ever see a 30 amp max imbalance.

Now if you go and try and feed 60 amps of 110 power the way you describe which is all in phase then your neutral is overloaded at 200%.

So, is your genset capable of making more than 30 amps of 110? If not, then you can safely feed both sides of the 30 amp breaker with 10/3 cable.

A nice benefit of this strategy is that your 30 amp 110 volt genset will be able to deliver all 30 amps to any 110 circuit or "side" of the panel.

If you reread the OP's first post, i think you will answer your own question. He said his generator only puts out max 30a 120v so he wouldn't be able to overload his neutral!

To the OP, if i did this setup, i would make sure to shut off any double pole breakers so you don't harm the appliance or generator in case someone accidentally turns the 240v appliances on not remembering that they wont work!

 

[matt151617]

I'll remember to, and I'm going to make a how-to taped into the panel for the wife in case she's home alone when the power goes off. How to switch off the main, flip off every single breaker, turn on the generator breaker, plug everything in, and then what breakers to turn on.

 

[bd8134]

Funny Matt, I did the same for instructions. Even used Dymo tape on the side of the generator on how to connect and start it..