Open ground question

[Jbird]

When testing my coach outlets with a plug in tester it indicates " open ground" on all circuits when I am powering with my portable generator. The GFI circuits do not break but show the same open ground. My tester plugged directly into the Honda generator also shows open ground.
A different power source to my coach, all circuits test properly. Can anyone explain why I show open ground in coach and at generator and am I in any danger in coach using generator for power. Thanks to the knowledgeable in advance

[wa8yxm]

To sum it up simply:

This is completly normal and is not a cause for concern. There is no danger.

[ktmrfs]

Salvo wrote:
The probability of 2 faults occurring is much greater than just one fault. That why the unbonded system is a lot safer. You don't need to rely on the GFI to work. They do fail.

BTW, the unbonded system has the same protections in regards to circuit breaker and GFCI. Add GFCI then three faults need to occur to get an "ouch". That system is virtually bullet proof. I'll take my chances any day of the year with those odds.

Should ground short to neutral or to hot (which isn't any big deal), I believe the 3-lite ac tester will pick it up.

Sal

SCClockDr wrote:
With the generator neutral & ground un-bonded:

If the neutral happens to short to ground and you make contact with the hot while grounded, ouch!

If the hot happens to short to ground and you make contact with the neutral while grounded, ouch!

If bonded then a hot to ground short trips the breaker on overload & a neutral short to ground will trip a GFCI breaker or outlet on ground fault if it is between the short and the bonded source.

Actually with respect to GFI outlets, the chances of them trippinng when connected to a unbonded generator is pretty remote. GFI won't trip if there is less than 5ma of current imbalance between hot an neutral. try tripping a GFI outlet when connected to an unbonded generator. Every GFI outlet I have tested, along with GFI testers will NOT trip the GFI when connected to my unbonded honda 2000. For it to trip there would need to be a leakage path from hot through the trailer and the tires/jacks, back to the generator plastic case, and up to the generator neutral to trip the GFI. Unless it is really wet outside that is unlikely to happen. so, if you do get across a 120V GFI circuit, more than likely ALL the current through you is going from hot to neutral and the GFI won't trip, end result, at least a pretty nasty shock.

However, I still feel safer with an unbonded generator.

[ktmrfs]

Wayne Dohnal wrote:

If the hot happens to short to ground and you make contact with the neutral while grounded, ouch!

If bonded then a hot to ground short trips the breaker on overload & a neutral short to ground will trip a GFCI breaker or outlet on ground fault if it is between the short and the bonded source.

AFAIK I'm the only one on the forum who has taken the position that there's not a clear "winner" with bonded vs. unbonded. With some faults, unbonded is clearly safer. With other faults, as noted above, unbonded just masks the problem and creates a hazard at the same time. If you don't know what fault your system is going to have, you don't know which is the better way to go. Fortunately, faults are rare, which I why I believe that either method is permitted with small generators. If one way or the other were clearly superior I assume the codes would be changed to require it.

your not the only one, I also agree with you. When your hooked to shore power, you should have a bonded ground/neutral a the post, same as a house so trailer ground is REALLY ground. when not hooked to shore power bonded neutral/ground at the generator has cases that would protect you, others that won't. So it's a "crapshoot". I have a "bonding" plug for my generator, but usually just bypass my EMS when hooked to the generator.

[Salvo]

The probability of 2 faults occurring is much greater than just one fault. That why the unbonded system is a lot safer. You don't need to rely on the GFI to work. They do fail.

BTW, the unbonded system has the same protections in regards to circuit breaker and GFCI. Add GFCI then three faults need to occur to get an "ouch". That system is virtually bullet proof. I'll take my chances any day of the year with those odds.

Should ground short to neutral or to hot (which isn't any big deal), I believe the 3-lite ac tester will pick it up.

Sal

SCClockDr wrote:
With the generator neutral & ground un-bonded:

If the neutral happens to short to ground and you make contact with the hot while grounded, ouch!

If the hot happens to short to ground and you make contact with the neutral while grounded, ouch!

If bonded then a hot to ground short trips the breaker on overload & a neutral short to ground will trip a GFCI breaker or outlet on ground fault if it is between the short and the bonded source.

[Jbird]

smkettner wrote:

Jbird wrote:
Thanks folks. After reading the link re grounding generators I see I have had the open ground issue with a generator for 9 years thru two fivers and have just now discovered it because of other electrical problems. So it's either not to worry or Im living on borrowed time when using my generator. The link seems to encourage either view. Thanks again

What are the other issues? We can help with those but the rest is normal.

I appear to have lost one hot side of 50 amp in from one of two sources to transfer switch. Either bad transfer switch or bad source. Haven't had time to check it out yet.

[Wayne_Dohnal]

If the hot happens to short to ground and you make contact with the neutral while grounded, ouch!

If bonded then a hot to ground short trips the breaker on overload & a neutral short to ground will trip a GFCI breaker or outlet on ground fault if it is between the short and the bonded source.

AFAIK I'm the only one on the forum who has taken the position that there's not a clear "winner" with bonded vs. unbonded. With some faults, unbonded is clearly safer. With other faults, as noted above, unbonded just masks the problem and creates a hazard at the same time. If you don't know what fault your system is going to have, you don't know which is the better way to go. Fortunately, faults are rare, which I why I believe that either method is permitted with small generators. If one way or the other were clearly superior I assume the codes would be changed to require it.

[SCClockDr]

With the generator neutral & ground un-bonded:

If the neutral happens to short to ground and you make contact with the hot while grounded, ouch!

If the hot happens to short to ground and you make contact with the neutral while grounded, ouch!

If bonded then a hot to ground short trips the breaker on overload & a neutral short to ground will trip a GFCI breaker or outlet on ground fault if it is between the short and the bonded source.

That is how I see it. 22 years Naval experience living in a steel pipe (submarine) for 10 of them. The neutral & ground were bonded in that environment.

[MEXICOWANDERER]

As long as it decides to not use me as a path...

[time2roll]

Jbird wrote:
Thanks folks. After reading the link re grounding generators I see I have had the open ground issue with a generator for 9 years thru two fivers and have just now discovered it because of other electrical problems. So it's either not to worry or Im living on borrowed time when using my generator. The link seems to encourage either view. Thanks again

What are the other issues? We can help with those but the rest is normal.

[time2roll]

Jbird wrote:
When testing my coach outlets with a plug in tester it indicates " open ground" on all circuits when I am powering with my portable generator. The GFI circuits do not break but show the same open ground. My tester plugged directly into the Honda generator also shows open ground.
A different power source to my coach, all circuits test properly. Can anyone explain why I show open ground in coach and at generator and am I in any danger in coach using generator for power. Thanks to the knowledgeable in advance

Normal and no additional hazards.

[tvman44]

Most ginnys have no ground.

[Salvo]

If it wasn't for lighting strikes, I doubt we would have bonded electrical systems.

Sal

rockhillmanor wrote:
'Why' does a generator need to be and/or is not grounded?

[Wayne_Dohnal]

'Why' does a generator need to be and/or is not grounded? I ask not being an electrician so go easy on me.

Here are some threads about it from before the time I was burned out over it. Some of the posts fit "go easy", others don't. As you can see, it's not a new issue.

Bonding a generator (9 pages)
Do You Ground Your Portable Generator? (9 pages)
Grounding Generators (41 pages)
NEC ground vs bonding (6 pages)

"You can drop a hair dryer into a bathtub with you in it without getting killed if the electrical system is unbonded." I agree but I'll be darned if I'm going to test out the theory!

[rockhillmanor]

'Why' does a generator need to be and/or is not grounded? I ask not being an electrician so go easy on me.

[Salvo]

Don't worry, you're not living on borrowed time. It's a lot safer keeping the gen unbonded. You're one fault away from a (fatal) shock if bonded, you're two faults away from a (fatal) shock if unbonded.

You can drop a hair dryer into a bathtub with you in it without getting killed if the electrical system is unbonded. Do not try that with a bonded system.

Sal

Jbird wrote:
So it's either not to worry or Im living on borrowed time when using my generator.