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DAJ
@myvzw.com

DAJ to garys_2k

Anon

to garys_2k

Re: Generator doesn't work with Direct Vent Hot Water Heater

I have read the 5 pages of responses here and I just wanted to be clear. Assuming one only has a portable generator NOT connected to the house beyond extension cords (no transfer switch) is using the generator's grounding screw connected to a proper ground able to solve the neutral/grounding issue for the hot water? It sounds like the 6" extension cord modification does the trick but I was hoping for something a little more mainstream.

garys_2k
Premium Member
join:2004-05-07
Farmington, MI

garys_2k

Premium Member

said by DAJ :

I have read the 5 pages of responses here and I just wanted to be clear. Assuming one only has a portable generator NOT connected to the house beyond extension cords (no transfer switch) is using the generator's grounding screw connected to a proper ground able to solve the neutral/grounding issue for the hot water? It sounds like the 6" extension cord modification does the trick but I was hoping for something a little more mainstream.

No, connecting the generator's ground terminal to the house's ground system will NOT change the generator's neutral-ground bond type. Definitely DO connect the generator's ground to the house's ground, but using the cord will "fix" that bond issue.

To make the fix more mainstream you'd want to make a permanent connection in the generator's electrical panel, screwing down one of the neutral wires to the generator's frame (which should already be connected to its outlets' ground wires).

TheTechGuru
join:2004-03-25
TEXAS

TheTechGuru

Member

said by garys_2k:

No, connecting the generator's ground terminal to the house's ground system will NOT change the generator's neutral-ground bond type. Definitely DO connect the generator's ground to the house's ground, but using the cord will "fix" that bond issue.

Connecting BOTH the common AND ground from the generator to the common/ground rail in the main circuit panel of the house will fix the problem and while one is in there might as well connect the hot(s) from the generator to the appropriate rails in there. Just turn off the main so you don't back feed.

alkizmo
join:2007-06-25
Pierrefonds, QC

1 edit

alkizmo to DAJ

Member

to DAJ
said by DAJ :

It sounds like the 6" extension cord modification does the trick but I was hoping for something a little more mainstream.

The proper way is to open up the receptacles panel on the generator and put a jumper wire behind the breakers between the neutral and ground using a 10AWG copper wire on the biggest lugs you can find that are linked to neutral and ground.

However, it can be tricky to open up that panel. Mine was sealed pretty tight, and I didn't have a lot of wire lenght to pull out the panel without disconnecting it completely from the generator (Which would have been very tricky as well).

Here's what I did for my mainstream setup:

My transfer switch handles the hot AND the neutral, so when I switch to the generator, the N/G bond in my electrical panel is no longer in the mix.

My generator's ground is still linked to the house ground through a #6 bare copper. That wire goes from the generator's ground lug and is tied by a split bolt to the house's ground conductor (Another #6 bare copper that is tied to my cold water copper pipe).

So with the N/G bond from the electrical panel broken because the transfer switch cuts the neutral off, I had to make a N/G bond at the generator. What I did is jump the neutral and ground from the inside of the L5-20P (plug) that connects to the generator to feed my transfer switch.

That way, when I connect my generator to the house transfer switch, the bond is created. When I disconnect the generator from the house, the bond is broken. No permanent modifications need to be done/undone on the generator itself.

Is it proper? Yup. The N/G bond is as close to the source (Generator) as it needs to be. The N/G bond cannot be removed without disconnecting the generator from the house. The ground bare copper wire still remains connected to the house ground, but that is of no impact, because there is no more bond between ground/neutral. It just helps avoiding static build up on the generator chassis if it is running but not connected to the house.

garys_2k
Premium Member
join:2004-05-07
Farmington, MI

garys_2k to TheTechGuru

Premium Member

to TheTechGuru
said by TheTechGuru:

said by garys_2k:

No, connecting the generator's ground terminal to the house's ground system will NOT change the generator's neutral-ground bond type. Definitely DO connect the generator's ground to the house's ground, but using the cord will "fix" that bond issue.

Connecting BOTH the common AND ground from the generator to the common/ground rail in the main circuit panel of the house will fix the problem and while one is in there might as well connect the hot(s) from the generator to the appropriate rails in there. Just turn off the main so you don't back feed.

That's where we part ways. Connecting the generator's neutral and ground to the panel's common rail is fine, but tying the generator's hots to the panel's hot rails and turning off the main is NOT what I'd do.

Some panels have more than one "main" (six lever rule), no wires should connect directly to the rails (should go through a breaker) and a physical method of preventing both the main(s) and the generator's feed breaker from both connecting to the hot rails at the same time should be used, even for temporary or emergency use.

Since the more recent questions are regarding this one use (hot water heater that needs its power source to have N-G bond) then I'd leave the panel closed and do my wiring at the heater PLUS the ground line from the generator's ground terminal to the electrical system's ground.

GenNewbie
@rr.com

GenNewbie to garys_2k

Anon

to garys_2k
Thanks for all of the replies. Here is what I have and what I plan to do. My house is 10 years old so has a relatively modern electric system. There is no PEX or plastic supply lines in the water supply system, it is 100% copper pipe. My main water supply line comes in near the main 200 amp electric panel and is grounded via a thick unsheathed cooper wire. I can see that ground wire running between the water supply and service panel, they are only about 6 feet away from each other. I can also see a clear cooper run of pipe that goes from that area, across the basement to supply cold water to my propane hot water heater. The hot water heater has the same thick braided copper wire jumping hot and cold pipe on the water heater. Based on this I ASSUME that the jumper is a proper ground as I can see the clear, uninterupted run of cooper pipe, the hook up to the main panel and the jumper on the water heater.

If I make-up the modified extension cord (thanks for the picture it confirmed what I needed to do!) and tie the generator ground into the exposed jumper/ground on the water heater (which I truly believe to be 100% grounded based on the above), it is as safe as it can get?

garys_2k
Premium Member
join:2004-05-07
Farmington, MI

garys_2k

Premium Member

said by GenNewbie :

Thanks for all of the replies. Here is what I have and what I plan to do. My house is 10 years old so has a relatively modern electric system. There is no PEX or plastic supply lines in the water supply system, it is 100% copper pipe. My main water supply line comes in near the main 200 amp electric panel and is grounded via a thick unsheathed cooper wire. I can see that ground wire running between the water supply and service panel, they are only about 6 feet away from each other. I can also see a clear cooper run of pipe that goes from that area, across the basement to supply cold water to my propane hot water heater. The hot water heater has the same thick braided copper wire jumping hot and cold pipe on the water heater. Based on this I ASSUME that the jumper is a proper ground as I can see the clear, uninterupted run of cooper pipe, the hook up to the main panel and the jumper on the water heater.

If I make-up the modified extension cord (thanks for the picture it confirmed what I needed to do!) and tie the generator ground into the exposed jumper/ground on the water heater (which I truly believe to be 100% grounded based on the above), it is as safe as it can get?

Yes, then with the electrical-plumbing ground bond verified (and be REALLY sure) then grounding to the jumper between the hot and cold pipes ought to be alright, but it would be BETTER if you bonded it to the uninsulated line running from the panel to the piping. Can you do that?

GenNewbie
@rr.com

GenNewbie

Anon

The issue is that the electrical service and panel and water supply come in one side of the house and the furnace and hot water heater are on the opposite side near the buried propane tank, so I'd either have to run a 45 foot extension cord or 45 foot ground wire or somehow try to split the difference. By using the jumper "ground" on the HW heater I can use a 10 foot extension cord and ground wire and be on the side of the house out of the way (north side) and right outside one of those small basement sliding windows. It is very convenient to hook it up and keeps the fumes and noise away from windows and doors and length of runs for extension cord and ground wire down, which I understand to be helpful and safer?

I am very confident but not 100% sure the cooper is continuous. There is one short run of about 3 feet that I can't see but they would have had to piece something in and mixed copper and plastic which would make no sense and probably not up to code. Of course some things I do make no sense.

I gather the bare #6 copper is the ground wire of choice? Is there a suitable insulated ground wire that is acceptable. I think I've seen # 10 at Home Depot but not # 8 or #6 but I am not sure. Is the #10 OK? Thanks!!!

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

said by sk1939:

Some do, some don't, it depends highly on the transfer panel so you can't generalize. Interlock kits for example have a different approach.

I didn't generalize, you did. You said the NG bond cannot be at the generator when they are connected to a transfer switch. They certainly can with certain transfer switches.
said by sk1939:

If you know it's a kludge, why would you suggest it? It's like telling a kid that it's bad to have guns around other people, but go ahead and take it to school.

Frink isn't a kid, and he was given warnings.
It's more like giving a gun to an adult and telling him to avoid shooting with it, but if he has to then he should be very careful.

He did do a very good job with the NG bond trick
said by sk1939:

Yes, but the point of that is what when you need the bond to be at the panel once power is restored? That just creates more work for yourself.

I doubt you understand how a transfer switch with neutral switching works.
said by GenNewbie :

I gather the bare #6 copper is the ground wire of choice? Is there a suitable insulated ground wire that is acceptable. I think I've seen # 10 at Home Depot but not # 8 or #6 but I am not sure. Is the #10 OK? Thanks!!!

Im not sure what you're trying to do, but for grounding a 30A generator (7200W or lower), then #10 is ok. Buy it green colored just so the color coding matches its purpose.

sk1939
Premium Member
join:2010-10-23
Frederick, MD
ARRIS SB8200
Ubiquiti UDM-Pro
Juniper SRX320

sk1939

Premium Member

said by alkizmo:

"I didn't generalize, you did. You said the NG bond cannot be at the generator when they are connected to a transfer switch. They certainly can with certain transfer switches."

Sure they can be bonded at the transfer switch, but then it's classified under "Separately Derived Power Generation" in the NEC when you do that. Neutral switching is only required if the grounds are tied together, to avoid having the neutral above ground potential.

You still have to bond the ground and neutral at only one place.
said by alkizmo:

I doubt you understand how a transfer switch with neutral switching works.

I know exactly how a transfer switch with neutral switching works, and not all transfer switches work that way.

Don't ask to "learn" and for people to explain things when all you do is shoot down things that go against your preconcieved notions and ideas. It's similar to a child asking "why" to everything, that's just not how it's done is the simplest explanation.

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

said by sk1939:

Sure they can be bonded at the transfer switch, but then it's classified under "Separately Derived Power Generation" in the NEC when you do that.

Neutral switching is only required if the grounds are tied together, to avoid having the neutral above ground potential.

Yes you're right that it is classified as a Separately Derived system, but you're wrong about why neutral switching is required.

In a non-neutral-switching transfer switch, you still have to join the generator's ground to the house's ground.

You still have to bond the ground and neutral at only one place.

Neutral switching only serves to disconnect the N/G bond from the main panel when the generator already has a N/G bond.
said by sk1939:

I know exactly how a transfer switch with neutral switching works, and not all transfer switches work that way.

I know, maybe I should have said "SOME" transfer switches switch neutral, but you did say this...
said by sk1939:

As far as the N/G bond, it's not at the generator with a transfer switch, it's bonded at the panel.

You made it sound like N/G bond is never at the generator when connected to a transfer switch.
said by sk1939:

Don't ask to "learn" and for people to explain things when all you do is shoot down things that go against your preconcieved notions and ideas. It's similar to a child asking "why" to everything, that's just not how it's done is the simplest explanation.

I know plenty to understand the complicated explanation.
I shot down explanations that weren't correct, such as:

- N/G bond creates a potential path to ground which is more dangerous than with house wiring (That is not true, it is not more dangerous, it is AS dangerous).

- A short to grounded items such as copper pipes will not trip the breaker (That is not unique to generators with N/G bond, house wiring works like that as well).

My issue is that you guys made it sound like its riskier than if you used a transfer switch. A transfer switch simply prevents backfeeding. Grounding and neutral bonding can be done properly without the need for a transfer switch, you simply don't connect the hot to the house's panel's hot.

garys_2k
Premium Member
join:2004-05-07
Farmington, MI

garys_2k to GenNewbie

Premium Member

to GenNewbie
said by GenNewbie :

The issue is that the electrical service and panel and water supply come in one side of the house and the furnace and hot water heater are on the opposite side near the buried propane tank, so I'd either have to run a 45 foot extension cord or 45 foot ground wire or somehow try to split the difference. By using the jumper "ground" on the HW heater I can use a 10 foot extension cord and ground wire and be on the side of the house out of the way (north side) and right outside one of those small basement sliding windows. It is very convenient to hook it up and keeps the fumes and noise away from windows and doors and length of runs for extension cord and ground wire down, which I understand to be helpful and safer?

I am very confident but not 100% sure the cooper is continuous. There is one short run of about 3 feet that I can't see but they would have had to piece something in and mixed copper and plastic which would make no sense and probably not up to code. Of course some things I do make no sense.

I gather the bare #6 copper is the ground wire of choice? Is there a suitable insulated ground wire that is acceptable. I think I've seen # 10 at Home Depot but not # 8 or #6 but I am not sure. Is the #10 OK? Thanks!!!

Number 10 is fine for your generator and it sounds very much like the water pipe jumper is a solid ground, but if I had my druthers I'd put the ground onto the panel's ground wire. Can you get a longer piece of wire?

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

said by garys_2k:

but if I had my druthers I'd put the ground onto the panel's ground wire. Can you get a longer piece of wire?

It depends what is easier/closer.
In my case, I tied my generator's grounding conductor (The one that attaches to the generator chassis) to the copper wire that exited my main panel and went to the copper pipe, using a split bolt.

sk1939
Premium Member
join:2010-10-23
Frederick, MD
ARRIS SB8200
Ubiquiti UDM-Pro
Juniper SRX320

sk1939 to alkizmo

Premium Member

to alkizmo
said by alkizmo:

Neutral switching only serves to disconnect the N/G bond from the main panel when the generator already has a N/G bond.

Again, depends on your transfer panel. Some only flip between
main and generator lines, rather than in between each circuit, like this one.

»www.homedepot.com/h_d1/N ··· ApBhrY4Y
said by alkizmo:

You made it sound like N/G bond is never at the generator when connected to a transfer switch.

Perhaps I should have clarified that in general it is at the panel, but it may be at the tranfer switch depending on your switch. For 95% of homes it is still at the panel.
said by alkizmo:

My issue is that you guys made it sound like its riskier than if you used a transfer switch. A transfer switch simply prevents backfeeding. Grounding and neutral bonding can be done properly without the need for a transfer switch, you simply don't connect the hot to the house's panel's hot.

My issue isn't with the use of a transfer switch, it's with the half-assed neutral-ground solution you suggested. That is what is dangerous for a variety of reasons. Yes it can be done without a transfer switch, but the majority of people aren't going to know how and will do it wrong, the extension cord plug trick included.
said by alkizmo:

I shot down explanations that weren't correct, such as:

- A short to grounded items such as copper pipes will not trip the breaker (That is not unique to generators with N/G bond, house wiring works like that as well).

Never said it was, don't fill in the spaces yourself.
said by alkizmo:

Grounding and neutral bonding can be done properly without the need for a transfer switch, you simply don't connect the hot to the house's panel's hot.

The point of that is what exactly then? Some generators provide the ability on the genset itself to bond the neutral to ground. It dosen't really matter if you use an extension cord with a GFCI, or are powering things that don't have a high risk of shock, like a lamp. It's still important to have a ground though, via ground rod.