DIY Home Improvement Forum banner
1 - 20 of 27 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter · #1 ·
Hi guys. My breaker box is shown in the pic below. I currently have a 120v genie hooked up to the house through a dedicated plug outside. Problem is, It won't run my 240V well pump. My question is, if I hook a 240v genie up with this breaker box configuration, will I blow my light bulbs/kill my fridge/start a wire fire on 120v circuits?

I'm only concerned because I know this setup for a genie isn't to code. Any advice is appreciated.

20210621_113118.jpg
 

·
Registered
Joined
·
906 Posts
Your breaker box runs on 240 volts which is actually just two 120 volt lines that are 180 degrees out of phase with each other.

The feed (to or from) your breaker panel should consist of 4 wires. Two of them are hot (120 and 120), the white one is called a Neutral, and the bare or green wire is the earth ground.

So long as your generator hooks up properly to those wires (4 wire connection plug), you should be fine. Your "dedicated plug outside" should have 4 terminals, your generator should have 4 matching terminals, and the patch cord between them should have 4 matching terminals as well.

EDIT: Your generator breaker, as currently configured, is illegal and dangerous. That generator breaker should be at the top of the stack of breakers and must have a mechanical interlock to prevent you from turning on both the gen breaker and the main breaker at the same time.
 

·
Registered
Joined
·
9,552 Posts
That is, does the generator also have 120 volt outputs including a neutral prong hole (120 volts hot to neutral) in the 240 volt output receptacle?

A 240 volt only generator may not be connected to your home electrical system.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #4 ·
Your breaker box runs on 240 volts which is actually just two 120 volt lines that are 180 degrees out of phase with each other.

The feed (to or from) your breaker panel should consist of 4 wires. Two of them are hot (120 and 120), the white one is called a Neutral, and the bare or green wire is the earth ground.

So long as your generator hooks up properly to those wires (4 wire connection plug), you should be fine. Your "dedicated plug outside" should have 4 terminals, your generator should have 4 matching terminals, and the patch cord between them should have 4 matching terminals as well.

EDIT: Your generator breaker, as currently configured, is illegal and dangerous. That generator breaker should be at the top of the stack of breakers and must have a mechanical interlock to prevent you from turning on both the gen breaker and the main breaker at the same time.
Thank you for the input. Is it dangerous because it can start a fire or only because it is possible to feed power back to the grid?
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #5 ·
That is, does the generator also have 120 volt outputs including a neutral prong hole (120 volts hot to neutral) in the 240 volt output receptacle?

A 240 volt only generator may not be connected to your home electrical system.
The generator I am looking at is listed online for sale. This is the info plate. I believe it is a 120/240 model.


655684
 

·
Super Moderator
Joined
·
22,179 Posts
That generator can be connected to your panel. It will run you well pump AND 120 volt appliances. Your current connection will need to be rewired and a second hot wire added.
You also MUST move that generator breaker up to the top and install an interlock kit so that it is impossible for both the generator and the MAIN to be on at the same time. Saying you will remember to turn one off when the other is on, is not good enough. It must be impossible for both to be on at the same time.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #7 ·
That generator can be connected to your panel. It will run you well pump AND 120 volt appliances. Your current connection will need to be rewired and a second hot wire added.
You also MUST move that generator breaker up to the top and install an interlock kit so that it is impossible for both the generator and the MAIN to be on at the same time. Saying you will remember to turn one off when the other is on, is not good enough. It must be impossible for both to be on at the same time.
Referring to the bolded text. If I already have a 4 prong hookup on the house for the generator, I shouldn't need to do any new wiring correct.

I will purchase and install an interlock for the panel. I didn't wire it myself, the house came this way.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #9 ·
Without inspecting the current wiring there is no way to answer this. It depends on how they connected the current generator.
The current generator is just a portable unit plugged into a male 4 prong plug on the side of my garage. Does that help any?
 

·
Super Moderator
Joined
·
22,179 Posts
Does it power everything except the 240 volt devices or is half your circuits dead? I suspect they might have connected the two hot together to power everything. If they did that then it will be a direct short when you plug in the new generator.
 

·
Registered
Joined
·
3,456 Posts
That wiring is fine since it's 4-prong. Any 240V generator in the North American market will support 120/240V. There's lots of material out there on how 120/240V split-phase works.

The wiring installation sounds tip-top except for -

Holy smoke! You MUST have install a sliding-plate interlock so the generator breaker cannot be switched on at the same time as the utility main!!!! How come nobody else menioned this? :) :) :)

That usually means the generator breaker needs to be moved to the top of the panel wherever the interlock needs it to be. If you can't get one from the manufacturer, search the aftermarket - lots of manufacturers make these.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #12 · (Edited)
Does it power everything except the 240 volt devices or is half your circuits dead? I suspect they might have connected the two hot together to power everything. If they did that then it will be a direct short when you plug in the new generator.
Various circuits from each side of the panel work. I haven't tested everything but on the left, the lighting section, one bedroom, and garage work. On the right, both kitchen and the range circuit work. It's my understanding if half the circuits wee dead it would be either the right or the left half, correct? The only things that haven't worked that I've tried were 240v appliances.

Edit: is there a way to check for this if I cut the power and open up the plug and look at the breaker panel without the cover on?
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #14 ·
Clueless ... why dont you just make arrangements to connect the well pump to the generator, and forget gping through the panel.
I was hoping to use the generator for lights and refrigerators as well. Basically take care of all the necessary things with one plug. This is my first time using a generator and first year in the house so I don't know all the ins and outs of powering with a generator. Looks like I'll be getting power back from this outage around midnight tomorrow.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #16 ·
Wrong. It would be every other circuit on both sides of the panel.
Thank you for that. If I check every 120v circuit and they are all working with a 120v generator, can I assume that the wiring is not going to case a short as you described?
 

·
Super Moderator
Joined
·
22,179 Posts
If I check every 120v circuit and they are all working with a 120v generator, can I assume that the wiring is not going to case a short as you described?
Opposite. With a 120 generator only half the circuits should work unless they shorted to the two hots together to power everything. Then the question becomes where did they connect the two hots together? in the generator cord? the receptacle? at the breaker?
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #18 ·
Opposite. With a 120 generator only half the circuits should work unless they shorted to the two hots together to power everything. Then the question becomes where did they connect the two hots together? in the generator cord? the receptacle? at the breaker?
So as long as every other circuit isn't currently working on the 120v genie, the 240v genie should power everything and not cause a short?

Thank you for being so helpful with this issue.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #20 ·
I just got home and checked. Every circuit is working... oh crap.

I went to look for the splice from hot to hot and couldn't find it. So I went and checked my 3 pole to 4 pole connector (pictured) and found that this little connector is spitting 120 out of both "hots" that would account for why all my circuits work, correct?
 
1 - 20 of 27 Posts
Top