open ground on generator

[tornadowatchranch]

I have a dipole manual transfer switch and when I plugged the generator in (a 15,000 watt generac) and connected a speery outlet tester, it said that I had an open ground. I used a set of car jumper cables to ground from the grounding outlet on the generator to the ground rod that the house uses. When on utility power the outlet tests out fine. My electrician is doing some research so I thought I would put it here to see where it went.

Thanks in advance

 

[dex3361]

How many conductors are you running between the generator and the transfer switch? Do you have the ground and neutral bonded?

 

[tommu56]

are you running 4 wires from the generator?
1st hot
neut
ground
2nd hot

mort details of generator mfg type plug code on it like L14-20 = 4 wire 240/120 volt

tom

 

[tornadowatchranch]

generator to the switch is 4 wire
I don't know if they are bonded
NEMA 14-50

I will try to get some pics tomorrow if they are needed. Thanks for the help

 

[dex3361]

Does your transfer switch disconnect the utilities neutral?

 

[tornadowatchranch]

it appears to only switch the two hots.
the neutrals are on the left and in one of the close up pics
the overview show the place to plug in the generator (no comment on the need for double male plug--I know the dangers)
the bottom 100 amp breaker is run separate from the switch and goes to the barn. I don't need it out there and will then know that the power is back on. some of those wires you will see inside the transfer switch.
I hope this helps

 

[dex3361]

Do you have your generator grounded to a separate rod? What size and brand generator?

 

[tornadowatchranch]

generac ultra
you can see the grounding lug below the elec panel (green wire to it)
I used a set of 4 gauge car jumper cables to go to the same grounding rod the house uses. Perhaps it was corrosion on the copper rod as it has been out there for 14 years. Should I be using a separate rod? Some google-ing indicated I should use the same but am by no means an electrical expert

Generac Portable GP Series GP15000E Electric Start - 5734 - Norwall PowerSystems

This is where I got the generator and has some info

 

[schmism]

Does your transfer switch disconnect the utilities neutral?

wouldn't matter, the utilities neutral should be tied to your ground rod at your pannel per code

 

[schmism]

generac ultra
you can see the grounding lug below the elec panel (green wire to it)
I used a set of 4 gauge car jumper cables to go to the same grounding rod the house uses. Perhaps it was corrosion on the copper rod as it has been out there for 14 years. Should I be using a separate rod? Some google-ing indicated I should use the same but am by no means an electrical expert

that should be right, the ground lug on the genny to a ground rod yes.

couple of things to check
1) that your connection from the ground lug to the ground rod is good (something else other than a jumper cable)
2) that he ground lug is connected to something on the generator....

 

[dex3361]

I usually do the same by clamping my generator frame ground to the existing ground rod. Just curious. What size wire do you have running from the generator receptacle to the transfer switch? The rating of the generator is 15KW and that is probably a surge rating (15000W/240V= 62.5A), according to these amps (disregarding the surge rating of the generator) the minimum wire size should be #8 or #6 depending on the insulation. I know this is not the original question but it could cause you major issues during a power outage. The grounding issue is one I would begin by testing the ground (with the main power off by checking the ohms resistance from the generator transfer switch ground lug back to the ground rod. Does this transfer switch disconnect the whole house?

 

[tommu56]

The wiring looks correct from the picture

Be careful with this testing if you have an meter

I'd ring out the cord from the generator plug to plug first make sure you got all 4 wires conducting from plug to plug with an ohm meter.

Then plug generator in don't start it leave house on line circuit take an
voltage reading from the neutral bar to the frame of generator and the ground rod they should be all 0VAC.

Start gen and measure leave the switch to line from each generator line to the neutral bar make sure you have 120v on each line.

Then measure voltage from the gen lines to the ground wire / rod running to the meter socket (in picture behind transfer switch)again it should be 120v on each line.

Measure voltage from the ground wire/ rod to the frame of the generator then from neutral to the ground rod/wire both should be 0 again.

If no voltage is found on the last test check the resistance from the neutral bar in the transfer switch to the frame of the generator.

Do the same to the ground rod/ wire.

This should find the open in the ground circuit.

I would suggest switching to an inlet like a Hubble hbl2715 it is a30 amp 120/250v flanged inlet plug configuration is L14030P or use the equal 20 amp it they should fit in the box you have now.
Just to protect the people that are unaware of the hazard of dual plugs.

tom

tom

 

[tornadowatchranch]

looks like I have some work ahead of me. The game starts in a few hours and this week is crazy (building potatoe guns with the cub scouts) Will likely be next week before I get to this.

Honestly this has been installed for 2 years and I have never needed it but decided to test before an outage...shoulda done it long ago.

When you are on generator does everything test normal with those testers?

I will check cord size next time I am in the barn

The surge on the generator is 22,500 with 15k nominal

It is connected through a 50 amp breaker protected circuit and yes is does the whole house

 

[tommu56]

looks like I have some work ahead of me. The game starts in a few hours and this week is crazy (building potatoe guns with the cub scouts) Will likely be next week before I get to this.

Honestly this has been installed for 2 years and I have never needed it but decided to test before an outage...shoulda done it long ago.

When you are on generator does everything test normal with those testers?

Yes it should be the same as utility

I will check cord size next time I am in the barn

The surge on the generator is 22,500 with 15k nominal

It is connected through a 50 amp breaker protected circuit and yes is does the whole house

You would need a 50 amp inlet I was looking at wire in picture and it looked like it was around 10 gauge

tom

 

[Highbeam]

You have discovered that your genset, like most, has a floating neutral. This is a very confusing concept to many, including me, but I do know that the outlet tester will show fault. The floating neutral means that the neutral in the genset is not connected to the ground and that there will be voltage in the neutral.

It's confusing. Ground rods won't help.

Here's the answer to the FAQ on the champion power equipment website:

"
What is "floating neutral" and how does it affect my generator? (All Generators)

All Champion Power Equipment generators, with the exception of our 40012 and all CSA-certified generators sold in Canada, have a "floating neutral", meaning that the neutral circuit is not connected to the frame or to earth ground. This also means that both legs on the receptacle are hot legs, which is normal for floating neutral generators. As a result, there is no specific hot leg and neutral leg wiring arrangement for the generator winding connection to the receptacle. The floating neutral configuration is common for applications such as connection to a recreational vehicle and connection to home power where the transfer switch does not switch out the neutral to ground connection.

The floating neutral eliminates the potential of being shocked by contacting a hot leg and the generator frame at the same time, which could occur if an electrical device such as a hand held tool suffered from an internal short circuit.

Meters or other devices intended to indicate polarity may not properly indicate polarity on a floating neutral circuit. Polarity indicators generally measure the voltage across the neutral and ground connectors. In electrical systems where the neutral is bonded to ground, the voltage will be zero and correct polarity will be indicated. In systems where the neutral is not bonded to ground, voltage is also not expected across this connection. However, in a portable generator some very small current voltage readings can be recorded by sensitive volt meters. This voltage may be induced in the frame by the magnetic field of the generator. The current associated with this induced voltage and the risk of electrical shock are negligible. However, very sensitive polarity meters may interpret this voltage as an indication of reversed connections.

If you have an indication of reversed polarity, please check with the manufacturer of your meter to determine if that reading capability applies to the floating neutral output from a portable generator."

 

[JB4310]

I've heard of that floating neutral, not sure but I think that's what was explained to me about my Multiquip 3500 watt genny.

It has a 220 outlet but can't be used as a back up for a house panel, because it doesn't put out an even 110 on each leg. puts out good 220 across the 2 hot legs, but is inconsistent between 1 hot and neutral, got readings as low as 30 volts, up to 180 volts.

one guy told me it has to do with the way it's written on the machine, either 110/220 or 110-220.
Does anyone know if this makes any sense or is accurate?

JB.

 

[tommu56]

I've heard of that floating neutral, not sure but I think that's what was explained to me about my Multiquip 3500 watt genny.

It has a 220 outlet but can't be used as a back up for a house panel, because it doesn't put out an even 110 on each leg. puts out good 220 across the 2 hot legs, but is inconsistent between 1 hot and neutral, got readings as low as 30 volts, up to 180 volts.

one guy told me it has to do with the way it's written on the machine, either 110/220 or 110-220.
Does anyone know if this makes any sense or is accurate?

JB.

a friend has a Coleman gen that has the same problem with 220v out only.
not that I recommend it but we are electricians and he rewired it to give it 110-n-110 and ground also put in a 4 wire outlet of the L14-20 configuration

tom