Residential Generators

[Eddie_T]

Parkway has some interesting adapter cords . . . https://www.parkworld.us/generator-adapter-cord-c12.html?page=2

 

[hbiss]

Factory made suicide cords. hmy:

-Hal

 

[drcampbell]

I would like a smaller (4000 watts) ... generator ... for well pump and water heater. ...

Good luck powering up a full-size water heater with that, most of which consume 4500 watts.
If those were the only two loads, you might just get away with it, especially if the generator is out in the cold, by adding a relay that switches off the water heater when the well's level switch wants to turn the pump on. But wouldn't it make more sense to get a generator that's actually capable of handling the load?

I wonder if with inverters one could sync them using 2 units for 240v (would negate any inverter savings).

Read the fine print in the instruction manual. If you buy two generators, read both instruction manuals.
If the system is well designed, you won't lose any efficiency by synchronizing two generators for additional power. The inverters will put out as much power as the load is demanding, and they'll command the engines to turn only as fast as necessary to meet the demand.

 

[electrofelon]

I find the typical 5-6 kw consumer generators are fine for most houses around here. They can run the whole house, I just use an interlock. I just tell them not to cook a thanksgiving feast or dry clothes. I recommend they turn the water heater breaker off, but if they run out of hot water and got to have it, turn the water pump off or dont use any water while its heating. OF course there sometimes may be electric heat which I also tell them to turn off, but around here there isnt much elec heat or air conditioning. Had someone once want to be able to cook the thanksgiving feast off generator power....ok you got it $$$$$$.

 

[Eddie_T]

Good points! I hadn't checked my water heater requirements, it is 4500 watts so I am stuck with my 5000 watt generator. It just that most of the time I don't need near that much capacity. Synchronized generators are just parallel output for more wattage, not to achieve 240 volts. A better approach for me might be to get the smallest feasible inverter generator for steady loads (TV and lighting) and and just use the 5000 watt generator intermittently for pump and water heater, but not simultaneously. Refrigerator and freezer could probably run off a smaller generator (just not simultaneously).

 

[JPinVA]

Good points! I hadn't checked my water heater requirements, it is 4500 watts so I am stuck with my 5000 watt generator. It just that most of the time I don't need near that much capacity. Synchronized generators are just parallel output for more wattage, not to achieve 240 volts. A better approach for me might be to get the smallest feasible inverter generator for steady loads (TV and lighting) and and just use the 5000 watt generator intermittently for pump and water heater, but not simultaneously. Refrigerator and freezer could probably run off a smaller generator (just not simultaneously).

I designed a three source (including POCO) twin transfer switch system. My two backup sources are a 1.5kW Li-ion 1400Wh battery inverter and a 3.5kW portable generator. One TS is 10 circuits and one is 4 circuits. The 4 circuits can run off POCO, Generator, or battery backup. The ten circuits can run off POCO or generator. About 95% of the outages in my area are two hours or less. So the Li-ion battery is sufficient. Runs the sump pump, garage door opener, and the master bedroom (for a CPAP machine), and provides power for internet fiber.

If the outage is extended, I go to the portable generator, which runs the fridge, microwave, and Kureg (gotta have coffee!!!), and a few additional lighting circuits. The generator also runs a circuit that I use to recharge the Li-ion battery. This allows me to turn off the generator at times and still maintain the four basic circuits.

The TS switching is set up so I can run any combo of circuits on POCO, Generator, or battery.

This isn't for everyone. The homeowner needs to understand the loads. For example, when i run the microwave, that's the only thing I"m running off the generator.

 

[Eddie_T]

I'll probably just continue with the 5000 watt Coleman Powermate as outages are only 1 or 2 per year. When it expires I may do the 4000 watt 120v inverter generator and use a 3000 or 5000 watt step-up auto-transformer to supply 240v to the panel. With load shedding and forgetting the water heater it should work out OK. An auto- transformer would eliminate any concern about load balancing as well.

 

[GeorgeB]

I'll probably just continue with the 5000 watt Coleman Powermate as outages are only 1 or 2 per year. When it expires I may do the 4000 watt 120v inverter generator and use a 3000 or 5000 watt step-up auto-transformer to supply 240v to the panel. With load shedding and forgetting the water heater it should work out OK. An auto- transformer would eliminate any concern about load balancing as well.

I cannot think of a code compliant way to accomplish it, but I have 2 friends with back-woods cabins who have their small 240V water heaters wired to 120V. They heat slowly (1/4 power) but for short showers and hand washing, do fine.

 

[Eddie_T]

I cannot think of a code compliant way to accomplish it, but I have 2 friends with back-woods cabins who have their small 240V water heaters wired to 120V. They heat slowly (1/4 power) but for short showers and hand washing, do fine.

Thanks, I never thought of that approach.

 

[drcampbell]

I cannot think of a code compliant way to accomplish it ...

Dedicated transfer switch for the water heater that either connects it to the two ungrounded conductors from the panel, (240v) or one ungrounded and one grounded conductor from the generator, (120v) and never allows the generator conductors to be connected to the panel conductors.

 

[meternerd]

Linemen good luck?

Linemen good luck?

Top of the list: Either install a transfer switch (manual or automatic) or tell the client to plan on using a couple extension cords to power specific items. Under no circumstances allow the generator to be connected directly to the house power system (e.g., by plugging it into the dryer outlet). I know someone who used that method to connect the generator of his RV to his house during power outages. I could not talk him out of it. In his case, nothing bad ever happened. That means luck was involved: not his good luck but the good luck of the linemen working to restore power.

I would start asking questions. Examples:

1. Are there specific items they wish to have power during a utility outage?
2. Do they want the generator to start and take load automatically?
3. Pertaining to question 2, what if the utility outage happens when they are not at home (i.e., either at work or on vacation)?
4. For an extended outage, will they leave the generator running all night, or will they restart it each morning?
5. Also for an extended outage, how will they make sure they have enough fuel to keep the generator going?
6. Pertaining to question 5, is natural gas an option for the generator fuel?

Welcome to the forum.

Just a comment, not an argument.....Our utility has a requirement for a visible, lockable disconnect on all solar or wind generation. But...to my knowledge, none of the line crews ever open those disconnects during an outage. The policy is to "identify, isolate, test and ground" before going to work, so a home generator is not really a concern. For us, the biggest hazard is not backfeed, but damage or fire to customer generators when the utility power returns. If the generator is still connected, it could be smoked since it will probably be out of synch. Manual or automatic transfer with interlock is the only safe way to go.