Emergency Power Generator Connection Help Needed

[armylifer]

To all,

There is something that I did not say in my original post because I really did not want to get into this much detail. However, I think that now I have to clarify a couple of things.

First, I am currently using a 5000 continuous watt (6250 watt surge) output generator for emergencies. This generator is enough to power all the lights in the house + the travel trailer, house refrigerator and freezer. This is enough for short emergencies. It is not enough to power the well pump and the septic system pump. Therefore, we are using the travel trailer for bathroom facilities, when necessary during long power outages. What I was hoping to do is use the other two generators to add that additional power to the house and be able to use the bathroom facilities in the house, instead of the travel trailer. I know now that simply adding the additional generators into the power panel is not going to work. Thanks to all for that education.

One of the things that I did not say that probably needs to be said, is how I am currently using my one generator to power the house during power outages. Before I get into that description, please note that I know that I am doing what many people consider a bad practice, and that if not done correctly is even dangerous. All that being said, below is what I currently do.

My 5000 watt generator has three power receptacles. One receptacle is a 120/240 volt, 20 watt receptacle with a twist lock plug. The other two receptacles are 120 volt, 20 amp circuits. All of the generator receptacles are separate power sources and not tied together. Therefore, I am currently plugging the generator 120/240 volt, 20 amp twist lock receptacle into a 30 amp, 240 volt outlet in the home and back feeding generator power into my house power panel.

I am also at the same time plugging one of the generator 120 volt, 20 amp receptacles into a 20 amp 120 volt outlet in the house and simultaneously back feeding that into the house power panel.

I want it to be noted here that before I do this I always turn off the 200 amp main circuit breaker as well as all the circuit breakers that I do not want to have power supplied to. This is a manual method of doing exactly what an emergency power panel does automatically. I am stressing the fact that I know that this is potentially dangerous if not done properly and asking that all who would advise against this method to refrain from the warnings that I know would naturally want to be said.

The reason that I did not originally put this detail in my post is because I did not want people to jump on me for doing what is considered potentially unsafe. I know the potential dangers involved and I chose to do it anyway because I know how to do it without creating an unsafe situation. Until I retired a couple of years ago, I was a telecommunications engineer and I have had some limited training in power applications, mainly for telephone systems but the theory and safety practices are similar for this kind of power application, so I am not totally unfamiliar with the potential for mishap.

Anyway, my goal in this thread was to try to utilize all of my current generators, if possible. I wanted to upgrade to a simple system that my wife can use if something should happen to me. In other words a system that safe and fool proof, while utilizing equipment that I already have with minimal investment in new equipment.

 

[North Idaho Wolfman]

I hate to tell you this, but all the plugs on the unit are off of the same 5000 watts.
Thus it's the same power being divided between all the Outlets.
Your not getting 2160 watts out of each of the 120 plugs and 4800 watts out of the 240 plug.

You should be using the 5000 watt gen to run the pump and septic as they are the only 2 really needing 240.
Then break out the 2 2000's for lighting and frig operation.
This can be done simply and safely with minimal cost by adding a small panel with breakers that cut them from the main feed and swap them over to a plug that you can plug the gens into.

 

[Greenhead]

Lots of different options. I had this interlock installed into the house/panel and there is a gen plug on the outside of the house. I too use a HF 7000w gen set and it's very good. I run synthetic oil after break in and always run it out of fuel via gas shut off when i'm finished. Always starts on the second pull. The electrician who installed the interlock never saw such a thing and thought it was very smart, simple, and safe. https://www.geninterlock.com/how-it-works/

 

[sagor]

Guys, be very careful with transfer panels, there are two types due to two different wiring schemes for generators.
Your typical portable gas generator, either cord start or electric start, usually have their neutral bonded to the frame, and that frame must be grounded. In many jurisdictions, electrical code clearly states that a house must have one and only one "ground". That means most portable generator transfer switches must transfer the neutral/ground as well as power. In my case, I have a fixed (automatic) backup generator where the neutral is floating, and my automatic transfer panel only switches the two power lines (120+120) as the neutral is bonded to the house neutral, which has the "only" one point of earth ground at the service panel.
Electrical codes may differ, as do generator designs. Hence it is best to get a qualified electrician that has done backup generators to install your transfer system. As a note, there are some electricians that do NOT know how to wire backup generators, make sure you get one that knows the code for your area. Also, some vendors will sell a panel that is legal in one area, but not in another - check that the panel matches your generator.

To answer the first question, no, you cannot parallel different generators. The issue is that their phases (sine wave) will be at different points of the sine wave, and one generator will feed power into the other generator, possible seeing a dead short if the phases are 180 degrees apart. If you need more power, get a bigger generator, or limit the loads on your transfer panel to match the generator. I have a 7.5KW generator, and the transfer panel only has a few essentials - water pump, furnace, fridge, freezer, microwave, pellet stove, a few lights and of course my satellite TV system....
If you want to use more than one generator, they must be on different panels/circuits.

If you want something "safe and foolproof", get a larger automatic standby generator with an automatic transfer panel for your critical circuits. Your wife does not have to do anything, just watch it start up, switch over, and power what you need.

 

[armylifer]

Wolfman, the generator does provide separate 20 amp power to two of the receptacle circuits. The one 120/240 volt outlet has it's own 20 amp circuit breaker. This is a separate circuit from the two 120 volt receptacles.

The two 120 volt outlets have another 20 amp circuit breaker that is for both of those. So, I get a total of 20 available amps between the two 120 volt receptacles, and another separate 20 amps off the one 120/240 volt receptacle. I tested this with a multi-meter for voltage and an ammeter for current draw from each outlet. To be sure that each of the outlets were separate power circuits I tripped the circuit breakers for each one and tested the outlet that way. I have also attached the operation page from the manual for clarity.

So in summary, the one 120/240 volt outlet is separate from the two 120 volt outlets. The two 120 volt outlets are on the same 20 amp, 120 volt circuit. You have 120 volts available from each of those two 120 volt outlets, but only 20 amps available total between them.

 

[sagor]

So in summary, the one 120/240 volt outlet is separate from the two 120 volt outlets. The two 120 volt outlets are on the same 20 amp, 120 volt circuit. You have 120 volts available from each of those two 120 volt outlets, but only 20 amps available total between them.

A 5000W generator cannot generate (steady state) more than 5000W. a 240V circuit at 20A is 4800W. You cannot load the 120V circuit at 20A at the same time your 240V is drawing 20A, that would be 4800+2400 = 7200W. (or 4800W plus two 120V at 20A = 9600W)

The 20A is probably based on the maximum current the alternator wires can handle, either on the 240 circuit or 120V circuit, or a balance on both. That is, you can draw 15A on a 240V circuit, then 5A on each leg of the 120V circuits (two 120V at 5A), since they would be fed off the main 120/240 alternator. Generators (higher power) only use one winding to produce the power, a 120/240V which is really a 240V with a split winding giving 120V each leg.
You can use any combination of loads, as long as you do not exceed the overall ratings. the 20A breakers are just a safety measure to prevent over currents. Some generators may have different winding, but you have to look at the total load vs the rating of the generator itself.
My bet is that if you are drawing 15A on the 240V circuit, then draw 10 or 15A on any 120V leg, the 240V breaker will trip since the combine current on any one leg (120V leg on one side of the overall 240V) will be exceeded. Having separate breakers only ensures that if you only draw load on one type of circuit, you do not overload the windings of the alternator

 

[nick2010tundra]

As a Lineman, This is absolutely correct. Also as someone who has to leave his family for weeks at a time to restore other people, I will tell you I bought a generac Whole home generator. Cost wise considering the cost of a transfer panel and with portable generators not being true sine wave ( Cant run sensitive electronics or compressors or fridges or heat pumps, without causing damage long term). The generacs are a very reliable unit and automatically turn on when the power goes out.

However you do it. If you wire the house to plug a generator into it.. GET AN ELECTRICIAN. Done wrong and one can back feed electricity into the grid and any emergency electrician working to restore power at a power line down the path from you can be electrocuted...

As to expensive manual transfer switches... luckily some communities codes now accept block off plate switches.. massively less expensive.

What these do is actually block off access to what must be blocked, but can only be put in place when correct circuits are turned off. When in place it opens a port on the fuse panel you can plug a generator into to power items based on size of gen set.

see....
. https://www.interlockkit.com/
. http://www.nooutage.com/interlock_kits.htm
. https://www.homedepot.com/p/Square-...r-Generator-Interlock-Kit-HOMRBGK2C/203030954

 

[nick2010tundra]

After reading your last response I think I should weigh in on your comments. First I respect that you worked for the telecommunications industry, and in no way do I wanna sound disrespectful. As a Lineman that works with electricity every day I will tell you right now that your idea of parelling 3 different generators will not work, hopefully when you try it, you won't burn your house down. probably you will cause the breakers on the smaller generators to trip and will have induced a under frequency trip, hopefully without damaging your house wiring ( Likely you will have cause a high fault though and you may not see it immediately, but likely will have damaged the insulation factor ( picture running your car at full rpm, then shooting nitrous oxide into it for 20 seconds, sure it still works but did you hurt it)
Maybe I can make a suggestion though on ho you could make this work for you though, hopefully without offending you at this point.
You could take your current well and make it so it plugs into a 30 amp nema receptacle, then plug the well direct into your largest generator. Then you could buy a small 30 or 60 amp generator panel for your other essential loads ( Lights ). Seeing as your experienced it should be no issue to wire a breaker in your main panel to feed this sub panel. Then you could feed it with one of your smaller generators.

Warning on Floating Neutral vs grounded Neutral Generators for other users

Most portable generators work on a floating neutral and use a modified sine wave, which is very hard on electronics and motors in fridges or wells. Also with these generators if you hook them up by backfeeding your panel and just opening your main you actually are damaging your generator because you are grounding the neutral of a generator that was designed to be floating. A proper generator sub panel will actually disconnect all 3 legs from the utility ( 2 hots and neutral ) so that you don't back feed the neutral with the imbalance or damage your generator.

If anyone would like to discuss feel free to pm me, hopefully I explained this decently and if anyone has questions feel free. IF you ever want help on codes or how to do this properly you can always ask a Utility Lineman, we don't bite and want you to have a good back-up setup for the just in cases
Anyways Sorry for the rant

 

[CaveCreekRay]

Nick,

My Westinghouse genset has a four wire (rotate and lock) connection from the generator to the generator isolation panel. Two leads are hot (one each phase 120v for a total of 220v.) One lead feeds one half (3) of the 110v isolation switches (house circuits) and the other 110v feed the other three. I remember at least one of the remaining wires from the genset house plug-in that wires to the generator isolation panel had ground and was wired to the ground bar in the panel.

Does that resolve the "floating ground" issue properly?

 

[nick2010tundra]

Nick,

My Westinghouse genset has a four wire (rotate and lock) connection to the generator isolation panel. Two leads are hot (one each phase 120v for a total of 220v.) One lead feeds one half (3) of the 110v isolation switches (house circuits) and the other 110v feed the other three. I remember at least one of the remaining wires from the genset house plug-in that wires to the generator isolation panel had ground and were wired to the ground bar in the panel.

Does that resolve the "floating ground" issue properly?

I can't say for certain ( have to see) but I would say you have one ground wire, which is basically making your generator and house at the same ground potential ( so you don't get a shock if you touch both at the same time **** PERFECT ****) The other would be a neutral wire
What you wanna check is that the neutral bus in the genset panel Physically seperates the neutral ( Usually white wire, unless Europe * IF so your on your own as there system is different *)

So basically you wanna make sure when you switch your handle to generator power it seperates all 3 wires, the 4th is using your house ground rod ( which is basically exactly that a rod driven in the ground to provide back up earth ground ) to ground your generator in case of leaking insulation or a fault.

I'm gonna try and add a photo for you so everyone can see the difference or link to a schematic

 

[nick2010tundra]

https://www.homedepot.ca/en/home/p....50sNLnMRRgcLtRriuQKNrB6pfKvUDiZgaAocVEALw_wcB

This is a suitable switch for a portable generator, I'm sorry I can't add pictures( don't know how) or draw a picture which would be even better.

The thing to notice in the description is that it uses a 3 pole main breaker, which allows it to switch the 2 hot legs and the neutral. That's why a proper generator disconnect is more expensive, they use a 3 phase breaker and instead of switching 3 hot legs they switch 2 hot and neutral.
IF I was doing a portable I would use Square D, which by the way is the only breaker that can also be used for dc application ( sorry Geeking out, I also do solar at my camp ), Square d's breakers actually switch off of a thermal reaction and are a far better breaker in my opinion.

Anyways I hope this helps an if someone knows how to add pictures and would like to insert a few for me I can do a little write up. hopefully I can save one lineman from getting hurt and possibly a few people from wrecking there generators.

By the way a descent electrician would not be costly for this as it is not a very labour intensive job by any means. If anyone is looking at an automatic whole home system I will tell you it cost more to have the gas hooked up than the electrical, and the propane tank was 20 feet away.

 

[KeithG]

First a disclaimer: I am not an electrician and I don't know anything about sine waves of power and the like.

What I have to offer is personal experience with a single 6000W with 7250 surge generator.

Back in 2008 the New England area suffered one of the most severe ice storm that took out power in the region for a very long time. I was able to purchase one of the last generators available at our local Home Depot stores and I contacted a friend who is licensed electrician to help me connect it up. Basically a 30 amp cord was used to go into a 30 amp breaker in my main panel.

Electrical specifics about my house: I put an addition on in 2000 that required a sub-panel to power the addition. So I have the main panel that was 200 amp that fed a 100 amp sub-panel at the other end of the house (in the addition). I have the following electrical components:
1) Well pump for water
2) Septic well pump for leach field
3) TWO refrigerators, on 25 yrs old one relatively new
4) Dishwasher
5) Stove/Oven appliance.
6) Oil fired forced hot air heat
7) Oil fired hot water supply and heat for addition
8) Electric base board heater for a room added that had no basement access
9) Washer and Dryer
10) Normal lights and electrical outlets for a home.

When the generator was connected the only thing I shut off was the electric base board heater.

For two days everything ran fine, absolutely no issues. On the third day my wife invited friends and families over to use our facilities to shower, etc...

This is where I found out the biggest threat to the generator is woman's vanity. I was checking the fuel level that morning I heard the generator lag terribly like it was going to seize or stall out. I ran into the house and yelled for them to turn off anything not needed. No effect. I went room to room and found the stove top on, tea pot on, two high heat flat irons, two high heat curling irons and two hair dryers! I turned off everything except the hair dryers that were being used. My daughter and wife immediately said "Hey!" To which I asked why do you need those and the reply was we were getting company today. I explained what was happening with the generator and they took turns using the needed hair items and the generator labored a little but did not sound as bad as earlier.

So I would say use your 5000W generator and listen to it running, you will know if it is powerful enough to handle your house or not. I would not use multiple generators on your home because I have heard that you could have issues with appliances and or computers. It has been 10 years since I used the generator for a full week and I have not had any issues with appliances.

I also did not use any "gentran" generator switches because the cost to wire one up to my main panel and sub-panel was just too expensive (i.e. money spent that did not need to be spent). So I just wired in the 30 amp breaker that is dedicated for generator use.

My 2 cents and experience....

The generator was about $600 back in 2008 and it is the best thing I have ever bought. Even though I have only used 3 times since then, there is nothing like having power when the main grid goes out...

 

[armylifer]

Thanks to all for the replies. My original questions were fully answered and I appreciate that. The additional information has been an education for sure, and I appreciate it.

 

[William1]

Glad we have some knowledgeable guys on the forum. Ask a question and there is sure to be someone who has the real skinny.

I have a additional question, sort of along the same lines as the OP.
I have 2) 200 amp panels in my home. One feeds the first floor, one feeds the second. The first floor panel is a Reliance Genset transfer panel with a four wire 50 amp twist lock for the generator cable. No transfer panel for the second panel. But I do have a four wire 240V 'outlet'. I've been using the twist lock for the first floor and a second cable to the 'outlet' for the second floor. Of course, main breakers to the meter are always switch off. I also have watt meters on both panels, total I have used (combined both floors) at any one time is not even 10,000 watts. I have a 'portable' GENRAC 17,500 genset.

Here is the actual question.
Is there a problem running cables to each floor like I am, running both at the same time? Don't breakers isolate the black and red legs, with only the white neutral and green grounds 'shared' and always active?

I have to run my genset at least once a year for a half day. I'd love to have a automatic whole home setup but no gas and no large propane tank here yet. If and when I do, I will have the transfer switch between the meter and both my panels, if I can afford it!

 

[7635tools]

Why mess around with three portable generators? Seems like a waste of time to me. One whole house generator with a transfer switch and your done. Installing one is not that hard.


Sent from my iPhone using Tapatalk

 

[mattwithcats]

See my posts on the first page...

This Old House explains how to hook up a portable generator,
and I posted a link to the smaller six port transfer switch.

They used a ten...

I also suggest you use Ideal Push In wire nuts,
I have fallen in love with these.

http://www.idealindustries.ca/products/wire_termination/push-in/in-sure.php

 

[KeithG]

Correction to my earlier post, my generator is 5,700W not 6,000W and the surge is 7,125W not 7,250W.

In my opinion generator switches are waste of money, put in a mechanical switch that prevents back feeding to the main grid and have the generator feed you electrical panel directly. That way you get power to all sources needing electricity just only turn on the ones you need.

If you really do not like the generator being wired directly into your panel you can buy a dual pole single throw switch (I think Centurion makes one) and you feed the main grid power to one pole and the generator to the second pole and the output line from this switch feeds the panel...

 

[jordan2140]

Thanks to all for the replies. My original questions were fully answered and I appreciate that. The additional information has been an education for sure, and I appreciate it.

Can I ask if you are using a power cord with two male ends under your current setup?

 

[armylifer]

Can I ask if you are using a power cord with two male ends under your current setup?

That is exactly what I am currently doing. I wanted to change that though because of obvious reasons. I am going to have a transfer switch wired into the power panel though. I have already contacted an electrician about doing this. He is going to make a site visit and give me a quote for it.

 

[jordan2140]

Not trying to dog pile but this is the piece that would scare me the most. A safe and budget conscious plan would be to get the interlock switch for your existing panel, install a recessed male receptacle, and you could easily replace your dryer and generator cord with a female locking plug (just guessing you used the dryer as that is what most DIYers do).

Good luck!