Generator suggestion

What size/type generator would you recommend that will start up and run a home that is equipped up to a 5 ton air conditioning system for a period long enough to perform a full home inspection?

Somewhere around 18kw to 20kw for the 5 ton AC plus whatever else the home requirements are.

How do you plan to make the connections between the genset and the house panel?

Back feed through the dryer plug.

Another idea: Hook right into the panel through a breaker, Bring your own if you have to. Be sure the main disconnect is off.

Allot of the homes have fuse panels.

Sounds sort of risky to me. What if the power is off at the house for a valid reason and you come along and energize it. Better put 911 on speed dial!

This is an idea that could very likely end very badly so let’s give Frank all the help we can. JK, lol :slight_smile:

Frank are you seriously gonna lug a 20 kva generator around and try to back feed it into service panels? If so, pass me some of what you are smoking because I’m having trouble visualizing this.

If the house AC and all other needs for the inspection happen to hit teh suggested 18 kW, that will be a draw of 75 amps @ 240 volts…hopefully the 30 amp dryer breaker works as some dryer wire may get fried.

My advice: don’t do it!!

Hire an electrician to do this so he will have the liability when something goes wrong!!! Have the electrician remove the meter from the meter box also…can’t be too safe…the linemen will respect you!!

Back feeding a dryer plug is a horrible idea not to mention illegal. Forget to turn off the main and your 120/240 volt generator is sending 7200 volts back over the primary line that someone may be working on to restore the power. A transfer switch or some sort of breaker interlock is what you should use. When using an automatic transfer switch (ATS) the generator is required to be large enough to carry the entire connected load. A manual transfer switch allows the user to select loads as he chooses.

As others have advised I would suggest consulting a licensed electrician before you open yourself up to a huge amount of liability.

I didn’t mention that as everyone on this thread should know that…but it appeared that it was going to happen anyways…so I tried to protect the linemen…remove the meter socket as a disconnect!!

Yes your idea will offer protection to the linemen but IMO cutting the seal or lock off of the meter enclosure is also a poor idea when you should be installing the system correctly to begin with. Also plugging the meter back live when the utility power is restored isn’t such a great idea either.

I thought Forest Gump was from Alabama. I guess dumb ideas transcend state borders.

Stupid is as stupid does. :wink:

I understood that this was only for while the inspection was in progress but, there is no way to run that kind of load thru the dryer plug even if it were legal to do. Find another way to do this or disclaim it.

(1) How much will it cost to install a generator transfer switch for a 3-4 hour inspection?

(2) if the house disconnect is in the “off” position, no current will be drawn. I’ve seen a meter replaced by the utility with the triplex still intact at the masthead. I did not see them disconnect the triplex at the transformer.

Also, turning off the main does not disconnect the neutral and current can still flow through the neutral from the generator / house wiring to hydro line if wired improperly and cause injury to linemen.

As mentioned, consulting with a licensed electrician for the installation of a proper transfer switch is highly recommended.

As a home inspector that is a really bad Idea and illegal as stated by others. My guess is that no one wants to have the power restored thru normal channels, they want u to take on that liability, or perhaps they are trying to set u up for a law suit, my advise, RUN AND DON’t LOOK BACK.
Insist that power be restored and all breakers on at the time of inspection.

Peace to all

I can see your point in trying to do this on the cheap since it’s only for a short duration test. When providing my first answer I misunderstood what is trying to be accomplished here. After reading it again, the house has no power and the generator is being used for temporary power during a test of the electrical system?

Back-feeding is a common practice. I do it from my garage to the main panel. I shut off the main.

Yes, it is true that the neutral is still connected.

For a temporary connection, this is likely fine, though I would not recommend testing any appliances which have a real draw, as it will stall the generator.

For permanant connectivity, an engineering exercise is required to determine the true loading. I am involved in two large-scale generator projects at medical centers here in NY. In one instance, we will have three Caterpillar C175 generators paralleled, for a combined output of 7.5 megawats @ 4160 volts. True calculations are a daunting task. Mercifully, calculating the draw of a house is much easier. Look at the past utility bills over a 12-month period and take worst-case numbers.

As to switching, automatic transfer switches as availavle in residential sizes. You can also purchase manual transfer switches. BBM would likely be safest for the typical homeowner. Phase synchronization becomes a non-issue in these instances.