Anyone ever reconfigure generator outlets?

[Kevin W Johnson]

Ok, quick question, anyone ever reconfigure the outlets on a generator. I just got a new one at 5am this morning that has a 20 amp 240v circuit. Its supposed to be a better unit than the one coming in within the next hour, but that unit is supposed to have a 30a 240v circuit.

I don't want to open the box to the first one in case I decide to trade.....

So, is it possible to retask the outlets in order to make a 30a 240v?

[John Lanciani]

What size generator? 7kW = 29 amps at 240 volts so if the generator is smaller there is really no point. Not to mention that you'd run into issues with overcurrent protection and also probably wire size, too.

[Keith Hankins]

not quite sure what your asking here. If you mean can you make a 20A the same as a 30A then the answer is no? I don't see how a 20A unit can be better unless it has some other functionality that the 30 A That rating means two important things. A how many watts it can carry at the same time. There should be two ratings peak and continuous. Peak means it won't die if it hits a peak of that rating, the continous is more important thats what it will do under a load. The second important thing is the guage wire it will take to support it. A 20A which is what I've got (3500W) requires at least a 12A wire and an L620 or equivelant plug & recepticle. A 30A will require at a minimum 10Awg Wire and 30A rated recepticles and plugs. If you already have your connection wired for 30A then the 20 will work because the wire gauge is higher but you can't go the other way. I have mine wired with submersible pump wire for the distance to my recepticle. Please also take into account the distance from your generator to wiring box. If you plan to back wire into the house from say a 240 outlet, please remember to disconnect the main as you could hurt a lineman working on your power as you would be feeding voltage back out, and if the power comes back on and you have not done that your generator will burn up! Hope that answers your question. My next generaytor will be a whole house generator with an automatic throw.

[Kevin W Johnson]

The slightly smaller output unit is a homelite, has a suburu engine, and a three year warranty, but only 20a output on 240v. The slightly larger unit is a powermate, with a powermate branded engine, a 30a 240v oulet, not possitive on warranty but thinking 1 yr.

Issues related to wiring size, overload protection, etc don't concern me as I have the stuff needed to change that. My concern is how generators are typically built and if it can just be changed over. If the unit can do 20a 240v, and 20a 120v simultaniously, can the two outputs be retasked to 30a/10a for example?

I know I can't be the first and only to think about doing this.... I've just never opened a generator before to know how it's typically engineered.

I'm well aware of backfeed issues as well, my wife works for an electric utility so I'm probably more well versed on issues of that nature than most.

[Scott T Smith]

[QUOTE=Kevin W Johnson;1949759]If the unit can do 20a 240v, and 20a 120v simultaniously, can the two outputs be retasked to 30a/10a for example?

QUOTE]


Most likely not, because of the way that the generator windings work. You have two different legs each producing 20A. You can't combine them into the same leg.

The key number to remember concerning a generator is that it requires 1.8 engine hp to produce each 1KW. Thus, an 18hp engine can produce 10,000 watts output.

[Kevin W Johnson]

[QUOTE=Kevin W Johnson;1949759]If the unit can do 20a 240v, and 20a 120v simultaniously, can the two outputs be retasked to 30a/10a for example?

QUOTE]


Most likely not, because of the way that the generator windings work. You have two different legs each producing 20A. You can't combine them into the same leg.

The key number to remember concerning a generator is that it requires 1.8 engine hp to produce each 1KW. Thus, an 18hp engine can produce 10,000 watts output.

Ahhh, there's the answer I'm looking for, and one that makes sense. I hadn't thought about balanced windings....

I have about 45 minutes till the other units arrive, and at that point I'll decide which one to keep. My main issue is I'dlike to be able to run the heat pump, but it requires a 30a circuit, but the smaller unit is.. supposed to be a better quality generator.

One other thought is to make due with the better but smaller unit now, and plan on getting a bigger unit later with a transfer switch after the demand has leveled off.

[Kevin W Johnson]

Scott, the larger generator is 20a 120v, and 30a 240v, so balanced is out the window. The more I think about it, I'm thinking maybe the generator produces all 240v, and the 120v recepticles are one recepticle on each leg.

I did opt for the larger generator, for the option of running my heat pump. It did so, very well in fact this evening. It took a bit to bring the house to 75, from a start temp of 85, but it's nice to have a/c again. And while I'm not complaining, the icing on the cake is that the power just came back on an hour ago after all that. However it's currently storming again, so it may be short lived. At least I have a setup now for events like this in the future.

[Tom Fischer]

Just to add to the chatter, we had a 8 day power outage last summer, so I finally bought a large portable (17.5Kw) generac, and had the wiring installed by a licensed electrician. I don't any knowledge to help with the questions Kevin is asking. But I can add this. You can do a lot of damage to any motors in your house if the generator is not sized correctly, and you are not sure what you can run with it, and don't shut off other circuits that have motors.

When the electrician was setting mine up (transfer switch, etc), he told me that during the power outage last year, many people damaged their water pumps (no city water here). Most of these folks just plug a small generac (~5K) into the electric dryer outlet, and don't think about anything else. Apparently, the local plumber who installs water pumps was busy for the next month doing Remove and Replace. Some of them are down pretty deep. Expensive stuff.

[Scott T Smith]

Scott, the larger generator is 20a 120v, and 30a 240v, so balanced is out the window. The more I think about it, I'm thinking maybe the generator produces all 240v, and the 120v recepticles are one recepticle on each leg.

I did opt for the larger generator, for the option of running my heat pump. It did so, very well in fact this evening. It took a bit to bring the house to 75, from a start temp of 85, but it's nice to have a/c again. And while I'm not complaining, the icing on the cake is that the power just came back on an hour ago after all that. However it's currently storming again, so it may be short lived. At least I have a setup now for events like this in the future.

Kevin, you are correct re the way that the power is generated.

Presuming that your generator is gasoline, it is usually best to turn the fuel valve off while it's running so that you can empty the carb. They store better this way.

[Keith Hankins]

I said that when I bought Mine geez 20+ years ago during Hugo. It's a generac and Its been running fine since then. It was funny we had an ice storm in va once and was out for a week and 2 weeks later had a 2nd and was down for another week. They are nice to have. My only complaint about mine was it's a loud sucker. I absolutely love the honda's that purr like kittens. I have a 3500W unit that will run most of my house (i have gas) we are just carefull to unplug all that is not necessary. I was funny it would grunt the most when she would plug in her curling iron. Back when I first bought it I was bummed that it would not do my electric water heater. I found out later that I could have disconnected one of the elements and it would have workd. Oh well. I've had gas sense. Good luck as a former VA boy trying to get back home. Take care.

[Bruce Wrenn]

I found out later that I could have disconnected one of the elements and it would have workd. Oh well. I've had gas sense. Good luck as a former VA boy trying to get back home. Take care.Your water heater never uses both elements at the same time.

[Joseph Tarantino]

you now have the untimate power tool, kevin. you can make power. i got ours after the big northeast blackout. won't ever be without one again. no power is no fun.

[Kevin W Johnson]

Well, after taking a peak inside a modern generator, the answer is that I don't need to do a thing (to the unit I kept). The generator I decided to keep and use has a total output of about 46A. Each leg to the 240v outlet has 23A breakers. The manual even states "Maximum full load current may be drawn thru the 240v outlet provided it's the only outlet used."

The unit in question that I originally posted about, I got to look inside one of those as well. It can easily be changed to do what I was thinking. All it would need is a 30A twist lock outlet, and new/proper size breakers. Wire size is not an issue the way these are built. In fact the 120v outlets are simply wired downstream of the 240v outlet, one each leg. So the current wiring already handles the maximum current output.

I had just never had the chance to look inside a generator, and I knew the store wasn't going to let me open one up, hence the reason for my original question.