Any truth to voltage reading neutral to ground?

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ritelec

ritelec

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Jersey
Hello…

I picked up a generator last year figured I'd get it set up to plug in in case of a outage..

It's small with the inverter, Honda eu2000i. (single phase, 120v)

The specs show that it's ground is "floating".

If I take a multi meter reading from neutral to ground I get 60v.

It reminds me of a clean balanced power unit I have where they tap the center of the winding to create a ground and H to N is 120v and N to G is 60v … (I screwed up and didn't check H to G, but figure it would be 120, 60 or 0 :) )

I remember finding literature in one place and only one place last year when I was researching this unit that showed this configuration.

All the research I've been doing now shows only a floating neutral.. Two honda techs also say the neutral floats..

I'm considering removing the panel neutral wire when the generator is running as I don't want to send 60v on the neutral. I'm also curious what will happen to the neutral/ground of the generator if I bond it at the unit, or let it bond at the electric service bond.

I found this post and it mentions the voltage reading N to G is not a true voltage.

Should I disconnect all leggs at the panel, just disconnect hots and leave neutral and ground bonded?



attached, post and clean power, and honda sch.


Thank you
 
What you have is equal capacitance in windings and wiring between the two sides and ground. This forms a capacitive voltage divider. It cannot supply much current, so I suspect that the "phantom voltage" will go away if you use a low impedance voltmeter or a Wiggy.
 
There’s two ways around this:

The first is use a transformer (expensive)

The second involves a bit of surgery in the generator. Remove the centre tapped neutral>frame link and fit a L2>frame>neutral link. L1 becomes your hot.
Solidly ground the frame.

BTW
This is a common problem in the UK ;-)
 
I’ve thought of a 3rd option if you’re feeling suicidal.
Believe it or not, one I’ve seen done in the UK and was horrified and at the same time amazed/intrigued by it.

The generator frame was sat on varnished hardwood insulating blocks. L2 was grounded in the transfer switch, the frame was hot (120V) to ground while the transfer switch was closed and the generator running.
It worked perfectly safely so long as you didn’t touch the generator frame………?


“The ingenuity of man knows no bounds” Dr. Jacobus tenBroek.
 
GoldDigger said:
What you have is equal capacitance in windings and wiring between the two sides and ground. This forms a capacitive voltage divider. It cannot supply much current, so I suspect that the "phantom voltage" will go away if you use a low impedance voltmeter or a Wiggy.
Click to expand...
This could explain my Dairy customer that has 60v to ground at some of its overhead door locations. They have small step downs at doors for operators and flush control.
 
Haven't yet checked with wiggy. Was good to see the couple posts about "ghost" voltage and wire it to a regular switch leaving the neutral of service connected.

Now mentioning about decoupling it internally ( don't even see where to do that from the schematic ) and voltage on the chassis ????

I will let you know what I discover. I put it away for the weekend.


Maybe I should have gotten a 240v less expensive louder one.


It's all good. Thank you
 
That may actually be "technical power" with the center tap of a 120V secondary connected to ground and both hot and neutral at 60V from ground in opposite polarity.
 
Trust Current Readings

Trust Current Readings

A power quality Guru once told me at a seminar years ago when you are T-shooting
a problem: "voltage readings can lie; current readings always tell the truth" ;)
 
fmtjfw said:
Brits use center-grounded 120VAC for construction tools, essentially the same as our "Technical power"
Click to expand...

We do indeed use centre tapped 110V for power tools. It is the reason I mentioned this being a common problem in the UK. People buy a “site” generator and expect the electrician to perform miracles.

I believe this is for a domestic installation feeding just one line of 120-N. the generator would seem to be 120V centre tapped IE 60-0-60.

Getting a new generator would be my option and buy a 120-0-120V set.
 
There is no hazard here and no need to modify the generator. You have a generator that does not have its neutral connected to the frame of the generator. It is "floated" and is an ungrounded system. (The use of an ungrounded system to supply premises wiring at this voltage level is not permitted by the NEC)
When you connect it to the building electrical system via a transfer switch, the neutral of the generator will be connected to the neutral of the premises wiring system and it will become a grounded system via the service grounding electrode conductor and the grounding electrode(s). To be code compliant you will need an EGC between the generator and the building system.
 
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