Electricians, generator hookup advice needed

"I'm on Fire", thanks for posting the pictures. That's the Square D generator panel that Home Depot sells around here. I bought one but actually used it for a sub-panel in my pole barn. It does not switch the neutral wire. Looks like you have the bonding screw in place. Right? What's your logic for doing so? How many conductors do you run between your generator and the generator breaker? Is the generator frame connected to an earth grounding rod at the generator?

You're welcome. I wish I had one of those other switches in this thread but they were fairly pricey.

No, I don't have the bonding screw in place. If you look across the top where the neutrals have been landed all the way to the right you'll see a small "U" shaped cut-out. That is for the bond screw. I'm running 10/3 from the main panel to the switch and 10/3 from the outlet to the switch.

1 - Red
1 - Black
1 - White
1 - Bare

I didn't need the neutral bonding screw because it runs back to my 150a main panel and is grounded through that. My generator is also not grounded through the frame, it uses a four wire plug so grounds to the panel in the house when its hooked up. I had asked the electrician I hired to crawl around in my crawlspace if the neutral bond was required and was told no because of how I had run it all back to the main disconnect.

Wow, thanks for all the great info, we have the most nolagable members,thanks for answering my question above and beyond, I'm sure a lot of other members learned a lot from this,thanks again, Garry..

I'm On Fire wrote:You're welcome. I wish I had one of those other switches in this thread but they were fairly pricey.

No, I don't have the bonding screw in place. If you look across the top where the neutrals have been landed all the way to the right you'll see a small "U" shaped cut-out. That is for the bond screw. I'm running 10/3 from the main panel to the switch and 10/3 from the outlet to the switch.

1 - Red
1 - Black
1 - White
1 - Bare

I didn't need the neutral bonding screw because it runs back to my 150a main panel and is grounded through that. My generator is also not grounded through the frame, it uses a four wire plug so grounds to the panel in the house when its hooked up. I had asked the electrician I hired to crawl around in my crawlspace if the neutral bond was required and was told no because of how I had run it all back to the main disconnect.

Your installation is exactly how I would wire a generator or any remote sub-panel. Four conductors back to the main panel with no bonding at the sub-panel. That certainly meets code. What I'm not clear on is the conditions were a grounding rod connecting the generator frame to earth is needed. I'll have to read the code in more detail. I can see it being required on a non-portable type generator, e.g. a permanent emergency exit backup generator in an office building. For a portable generator I'm not sure. In any case the idea is to assure the generator frame or housing stays at earth potential. Somehow you need to protect a person with their feet on the ground when they touch it if you have a generator equipment failure that makes the generator frame hot. With the wiring you have it's only protected as long as the wiring is intact.

There is a place on my Generac to run a ground rod to the frame. There is a grounding block with a spot open for the rod. It doesn't explain when a grounding rod is required in the manual for the generator either. I too have been wondering when it is required myself.

My owners manual for the Yamaha says: "When the electrical device is grounded, then always the generator must be grounded."

But this makes no sense to me ... because if it's hooked up to the house, then every device is grounded ....???

Either way, I've never used the ground post on the gen.

Smitty, that's exactly what mine says. I read it several times and couldn't make heads nor tails of it.

just yesterday while swapping out argon tanks and reading the manual ( ) , cause it was there, I decided to make up and install a "ground" fron the case bolt to the ground.....

I used a 12ga high strand count wire and ran it along the verticle support down to the ground where I stripped and splayed out the strands so they touch and "sweep" the concrete floor as the welder is moved around. this is on the tig welder/plasma torch. the opinion I got was it was for any static electricity build up and i thought about all those chains that they drag under school buses........

figured it couldnt hurt, look cool, and kill time

I'm On Fire wrote:There is a place on my Generac to run a ground rod to the frame. There is a grounding block with a spot open for the rod. It doesn't explain when a grounding rod is required in the manual for the generator either. I too have been wondering when it is required myself.

I think what is being described in the generator manuals is an abundance of caution to protect against two failures. For example, assume the generator frame is not connected to an earth rod at the generator. Four wires, red (hot), black (hot), white (neutral), bare or green (safety ground) are connected to the service switch, like "I'm on Fires" installation described above.

Now assume there is a insulation failure in the generator, leaking some voltage to the generator frame. The resulting current is shunted to earth by traveling along the neutral and/or safety ground. The path is up to the transfer switch, into the main panel and out to the earth ground of the service entrance. All is well. So it seems.

Now let's assume you are using a portable type generator with a male-female plug connection and you remove the plug. As you do so you will be zapped because the generator frame is no longer grounded. If there was a earth ground rod at the generator you would be protected. So there were multiple things that had to go wrong.

Your level of protection comfort is up to you, but most safety codes are written to protect even if there are multiple failures.

Yanche wrote:Now let's assume you are using a portable type generator with a male-female plug connection and you remove the plug.

I'm thinking at the point you remove the plug leading from the gen to the xfer switch/Main Panel, and the generator is no longer connected to any dwelling, at this point, it truely is portable and you can wheel it around at will. Running, or not running. I don't think its frame being grounded to earth is covered by code. Once you connect to xfer panel/Main Panel, the generator should meet all code.

http://dma.mt.gov/des/library/genbrochurev3.PDF

Page three has some really good information on it. I'm trying to find out why it'd need to have a grounding rod.

Ok, I think I found it.

http://www.osha.gov/OshDoc/data_Hurrica ... erator.pdf

The above document explains why a ground rod or bonding would be required. But I still don't quite understand it.

I think I figured it out, a grounding rod on your generator is only required when the generator is used as a separately derived system. From what I can gather, a 'separately derived system" is one that does not have a switched neutral. The neutral is the same run throughout the circuit

But in the case where the generator is connected through a solid connection through a transfer switch and the connection between the generator and switch has its own ground then the generator does not require a grounding rod as the frame of the generator is the ground. In the case of my setup I do not require a grounding rod on my generator because my neutrals and grounds are separate.

Basically from what I gather if you backfeed through your washer circuit you need a grounding rod for your generator since your grounds and neutrals are all "landed" at the same point in your main panel. Aside from that backfeeding is dangerous as you run the risk of feeding power into the grid.

At least that's how I understand it.

I have a Honda 11K generator that I back feed my whole house with. The Honda has a GFCI circuit system and when you hook the generator up to the house the generator blows the two 50 Amp breakers on the generator. Honda Power has a fix for that problem, you remove a ground wire from the internal workings of the generator itself. Very simple and easy fix,I did it myself. They also give you a warning label to affix to the generator, warning that there is no more GFCI protection. So if you are going to use the generator not hooked up to the house you do not have the safty protection of the GFCI and they advise you not to use the generator.

Must be for static interference....highly ionized air in storm situations? could zap sensitive generator controls?

I found another document that explains what I was trying to say better last night.

http://www.imsasafety.org/journal/ma03/ma5.htm

And yup, seems that it's mostly there for static charges from lightening. But like I said, the rod is not required in all instances.

1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.

g350h wrote:I know a few people that when they lose power they turn off there main breaker, and back feed the panel by hooking a generator to the clothes dryer plug, 220. Is this safe? Would that make all the outlets 220? I don't mess around with electricity, just wanted to know of a safe way next time I lose power.

Besides all the great discussion so far, I will add the following.

Many clothes dryers outlets were once wired w/ 10/3. (2 wires and a ground)
therefore they will NOT provide the necessary neutral connection from a generator.

By definition...a "Ground" conductor is a "NON"-current carrying conductor...where a "Neutral" is a current carrying conductor.

And how would one get the cable into the house...crack a door or window? ...Carbon Monoxide!