Generator backup power

[TheMan419]

A little "house" or shelter for the gen set is pretty common. Of course you need to make sure the engine gets enough fresh air to run. Does not change the need to be far from a window or door to the home to prevent you from killing yourself with the exhaust.

Make sure you build in such a way to allow access to the until to change oil, make repairs etc. In my ideal world I would be a shed that I could then wheel the unit out of to do whatever maintenance etc was necessary.

 

[Larry Caldwell]

If anyone can clarify this part, that would be very appreciated.

There is no "negative" in alternating current. What you have in a 240v. supply is two 120v circuits that are 180 degrees out of phase with each other. When one is going positive, the other leg is going negative. The neutral only functions if there is an unbalanced load, more hooked to one leg than the other. Then the neutral completes the circuit for the excess amperage. If you have a balanced 240v load, like a well pump that runs on 240v. or a 240v. water heater, you do not need a neutral, just two hot legs and a ground. If you hook a light bulb to the generator, then you need a neutral. Everybody hooks up light bulbs, toasters, microwaves, etc., so a neutral is required.

If you pull the cover off of your house service panel, you will see two hot leads serving two breaker buss lines, and loads on either side in a rough attempt to balance the load. The neutral will be connected to a bunch of screw lugs along the side, and the neutral buss will also be bonded to the building ground. In theory, that keeps stray voltages from showing up on the neutral leg in 120v. circuits. In practice, the building ground can have up to a 25 ohm resistance, so there can be pretty good voltage on the neutral. That is why your generator instruction sheet will tell you to ground the generator. If you rely on the neutral, your generator frame can have enough voltage to give you a nasty shock if your feet are wet.

That NEMA 14-50 plug has provisions for two hots, a neutral, and a ground. How it wires to the transfer switch depends on the design of the transfer switch. It may feed a 2-pole breaker or it may wire to main lugs. The neutral and ground will both be bonded at the box. That is why a local ground for the generator frame is a really good idea. The neutral can pick up stray voltages just like the main electrical panel.

 

[LittleBill21]

you have to decide what works for you. we don't get enough outages here to have a built in generator. i own 2 generators a large one for well/oven/water heater and a small inverter one. the large one is only randomly used to take showers and cook, the rest of the time i switch back to the inverter and use 1/8 of the gas. most of the time ur not cooking or taking showers to need the big one anyway

to the first or second poster, you don't need to turn off most loads. i have a 7k continuous and can use my oven just fine, i can't use every burner, but u can figure out how hard u can push it. i run my big generator generally to full load when its hooked up

 

[fatjay]

Why do you say that a pto generator "ties up your tractor for hours at a time" ? When your lights go out, do you turn on all your flashlights and let them burn until the batteries go flat ? Do you turn on all your faucets and keep the water running ? Is your car running in the garage right now even though you are not using it ? Sounds like it the way some thinkers go...

Well, my wife and 2 daughters enjoy heat and running water. If I were to go out and snowblow I'd have to shut all those things down for 2-3 hours while I was snowblowing on the tractor.

 

[fatjay]

A little "house" or shelter for the gen set is pretty common. Of course you need to make sure the engine gets enough fresh air to run. Does not change the need to be far from a window or door to the home to prevent you from killing yourself with the exhaust.

Make sure you build in such a way to allow access to the until to change oil, make repairs etc. In my ideal world I would be a shed that I could then wheel the unit out of to do whatever maintenance etc was necessary.

That entire side of the house has no windows or doors. My thought was to put a ventilation fan plugged into the generator with a screened hole or dryer flap type thing, plugged into the generator. That way if the generator is running, the fan is on. The plan was to make a set of barn style doors that way it can open up. I could unplug it and wheel it to the garage for required maintenance, then wheel it back and hook it up again.

 

[fatjay]

There is no "negative" in alternating current. What you have in a 240v. supply is two 120v circuits that are 180 degrees out of phase with each other. When one is going positive, the other leg is going negative. The neutral only functions if there is an unbalanced load, more hooked to one leg than the other. Then the neutral completes the circuit for the excess amperage. If you have a balanced 240v load, like a well pump that runs on 240v. or a 240v. water heater, you do not need a neutral, just two hot legs and a ground. If you hook a light bulb to the generator, then you need a neutral. Everybody hooks up light bulbs, toasters, microwaves, etc., so a neutral is required.

If you pull the cover off of your house service panel, you will see two hot leads serving two breaker buss lines, and loads on either side in a rough attempt to balance the load. The neutral will be connected to a bunch of screw lugs along the side, and the neutral buss will also be bonded to the building ground. In theory, that keeps stray voltages from showing up on the neutral leg in 120v. circuits. In practice, the building ground can have up to a 25 ohm resistance, so there can be pretty good voltage on the neutral. That is why your generator instruction sheet will tell you to ground the generator. If you rely on the neutral, your generator frame can have enough voltage to give you a nasty shock if your feet are wet.

That NEMA 14-50 plug has provisions for two hots, a neutral, and a ground. How it wires to the transfer switch depends on the design of the transfer switch. It may feed a 2-pole breaker or it may wire to main lugs. The neutral and ground will both be bonded at the box. That is why a local ground for the generator frame is a really good idea. The neutral can pick up stray voltages just like the main electrical panel.

Thanks for clarifying the termonology, I'm used to working with DC. Please, if I call something by the wrong name, correct me.

I've taken my panel off many times and installed breakers for my basement and changed configuration and installed double's to free up spots. I added a subpanel when i installed my 220v dryer, the house was previously not wired for one. I finished my basement myself and did all the electrical, including an additional two breakers. I have a dedicated server room as well, which has 2 dedicated 20a breakers. So I'm at least partially familiar with the structure of my panel box. My whites all go to a common bus. My grounds all go to a steak in the ground outside. I plan to run an additional wire from the generator to the steak as well.

The plan is to use an interlock kit instead of a transfer switch. I've seen people use a 50a double pole breaker on one leg, but wouldn't that create an unbalance? Also are the two legs connected? Would it be better to use two single poles on opposite legs?

 

[LittleBill21]

Thanks for clarifying the termonology, I'm used to working with DC. Please, if I call something by the wrong name, correct me.

I've taken my panel off many times and installed breakers for my basement and changed configuration and installed double's to free up spots. I added a subpanel when i installed my 220v dryer, the house was previously not wired for one. I finished my basement myself and did all the electrical, including an additional two breakers. I have a dedicated server room as well, which has 2 dedicated 20a breakers. So I'm at least partially familiar with the structure of my panel box. My whites all go to a common bus. My grounds all go to a steak in the ground outside. I plan to run an additional wire from the generator to the steak as well.

The plan is to use an interlock kit instead of a transfer switch. I've seen people use a 50a double pole breaker on one leg, but wouldn't that create an unbalance? Also are the two legs connected? Would it be better to use two single poles on opposite legs?

your generator uses 240v , thus requires a breaker across both legs, do not use individual breakers. to be honest with the questions your asking you might want to run it by an electrician

your grounds also confuse me, they should be bonded in the main panel, with a single ground line going out side to ground rods, not sure why your doing individual runs

 

[fatjay]

I'm going to eventually, but I want to learn as much as I can before then. It's amazingly difficult to find this information, everything just says "hook up to the panel", but no details or explanation. Electricians want to "do it for you", not teach you, and I'm trying to learn.

I get it now. I was picturing a U configuration, I forgot that each leg has those fingers and they're alternating between the legs going down each side. It's been about a year since i took the breaker box apart and redid all the breakers. I don't work in the box often, so stuff slips away from me.

 

[Larry Caldwell]

Thanks for clarifying the termonology, I'm used to working with DC. Please, if I call something by the wrong name, correct me.

I've taken my panel off many times and installed breakers for my basement and changed configuration and installed double's to free up spots. I added a subpanel when i installed my 220v dryer, the house was previously not wired for one. I finished my basement myself and did all the electrical, including an additional two breakers. I have a dedicated server room as well, which has 2 dedicated 20a breakers. So I'm at least partially familiar with the structure of my panel box. My whites all go to a common bus. My grounds all go to a steak in the ground outside. I plan to run an additional wire from the generator to the steak as well.

The plan is to use an interlock kit instead of a transfer switch. I've seen people use a 50a double pole breaker on one leg, but wouldn't that create an unbalance? Also are the two legs connected? Would it be better to use two single poles on opposite legs?

You should go by your local farm store or home store and pick up a book that will show you all the connections in simple drawings. The one I use is something like "Wiring made simple," or something like that. It's packed away right now.

Your service entrance neutral bus should be bonded to the building ground (the stake in the ground outside). That is a NEC requirement, and you have to use heavy copper, 6 gauge if unprotected, for the connection between the ground and the panel. If all your grounds run out to that stake, it is wrong. Small wire is far too flimsy to make a reliable connection. Ground wires and neutral wires should all go into the neutral bus in the service panel. If you have sub-panels, you have to have a separate ground bus and neutral bus, but they both have to be in the sub-panel box. A couple decades ago the code required a separate ground at the barn, and each sub-panel wired like an independent service entrance panel, but they changed that. Now you have to run a ground wire back to the main service panel. You will still find older installations wired like a service entrance, but inspectors will not approve it any more.

A 50 A double pole breaker connects to both legs in the box, but I have no idea what kind of interlock you are talking about. All transfer switches are interlocks. They have nifty, easy-to-install transfer switches that fit between the meter and the meter base, or transfer switches that are in a separate box, but I don't know of anything you can install in your current service panel. Post a link to the product you have in mind.

PS: Modern grounding code requires either a UFER ground connected to foundation rebar, or two ground rods at least 6' apart and bonded together.

 

[LittleBill21]

but I don't know of anything you can install in your current service panel. Post a link to the product you have in mind.

GE PowerMark Gold Load Center/Generator Interlock Kit-THQLLX1 - The Home Depot