Before I ask my question, I will say I did do a search and couldn't find the answer. I have been using a Predator 3500 to power my RV for some time now and have no complaints. I do not use my Progressive EMS because it detects an open ground, which I understand. After watching some YouTube videos I decided to make a bonding plug so that I could use my EMS.Using my voltmeter I measured the voltage from ground to either side of the 120 volt outlet and found it to be 60 volts on either side. My question is what side do I wire to ground? The videos all seem to show 120 volts on one side and zero on the other. I am confused because I thought I would see 120 volts on the hot side, which is usually the right side of the plug, and zero on the left, or neutral side. I assume to make a bonding plug I would jumper between the left side of the socket to ground. But since I see 60 volts on the left side of the socket I need to be sure I am not going to damage my generator, hence the question.Thanks for the help in advance.

I am not sure what you have going on with the voltage , but the neutral is the larger blade on the plug.

You're seeing 60V precisely because the ground connection is floating with respect to the output. Due to various reasons that are not important here, it naturally tends to settle around the midpoint of the other lines, or 60V, if unloaded. Incidentally, if the ground and neutral were at the exact same voltage, the EMS would not be detecting an open ground.You need to bond the neutral to ground; once that is done, there will be zero volts between them and 120 volts between the hot and neutral and between the hot and ground.

You could wire up something to your plug like an incandescent bulb. Connect a wire to the green screw and to the silver screw (ground and neutral). If the voltage drops to zero you will be okay.

You guys are great! DrewE confirmed what I was suspecting was the case with my voltage readings. I went ahead and wired up a bonding plug and all is well now, my Progressive EMS works as it should now.Some have said you don't really need a surge protector or EMS while using an Inverter generator, but now I have a choice. Thanks again!

Tom_M wrote:You could wire up something to your plug like an incandescent bulb. Connect a wire to the green screw and to the silver screw (ground and neutral). If the voltage drops to zero you will be okay.Or said another way, the OP is read "ghost voltage", voltage that is really not there. This because a digital meter has extremely high input impedance, probably in the million ohm (mega-ohm) range. Old fashioned analog meters (like a Simpson 260) have an input impedance in the 10s or 100s of kila-ohm range. Enough to present a "load" and make the ghost voltage disappear.The same problem sometime happens when trouble shooting 12VDC circuit, which is why an old fashioned incandescent test light is often be than a DMM.

Predator 3500 Question | Good Sam Community

theoldwizard1
Explorer II
Jan 18, 2019
Tom_M wrote:
You could wire up something to your plug like an incandescent bulb. Connect a wire to the green screw and to the silver screw (ground and neutral). If the voltage drops to zero you will be okay.

Or said another way, the OP is read "ghost voltage", voltage that is really not there. This because a digital meter has extremely high input impedance, probably in the million ohm (mega-ohm) range. Old fashioned analog meters (like a Simpson 260) have an input impedance in the 10s or 100s of kila-ohm range. Enough to present a "load" and make the ghost voltage disappear.

The same problem sometime happens when trouble shooting 12VDC circuit, which is why an old fashioned incandescent test light is often be than a DMM.
Route_66_Travel
Explorer
Jan 18, 2019
You guys are great! DrewE confirmed what I was suspecting was the case with my voltage readings. I went ahead and wired up a bonding plug and all is well now, my Progressive EMS works as it should now.

Some have said you don't really need a surge protector or EMS while using an Inverter generator, but now I have a choice. Thanks again!
Tom_M1
Explorer
Jan 18, 2019
You could wire up something to your plug like an incandescent bulb. Connect a wire to the green screw and to the silver screw (ground and neutral). If the voltage drops to zero you will be okay.
DrewE
Explorer II
Jan 18, 2019
You're seeing 60V precisely because the ground connection is floating with respect to the output. Due to various reasons that are not important here, it naturally tends to settle around the midpoint of the other lines, or 60V, if unloaded. Incidentally, if the ground and neutral were at the exact same voltage, the EMS would not be detecting an open ground.

You need to bond the neutral to ground; once that is done, there will be zero volts between them and 120 volts between the hot and neutral and between the hot and ground.
dmck413
Explorer
Jan 18, 2019
I am not sure what you have going on with the voltage , but the neutral is the larger blade on the plug.

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