Floating Earth

If you asked me this actually is a feature because you're not restricted to have one of the output cables as ground. You could for example have ground at halve the output voltage, so the max voltage to ground would be halved too which can be used as a safety add-on feature in some applications. The fact that you got a shock probably means that your "piece of equipment" leaks to ground which is a problem on it's own

first... get a voltmeter and measure the voltage between every wired connection in the entire system.... measure the voltage from the rock solid ground to every wire... you will be looking for very low values... if there are any bad connections you will read a voltage... you should NOT have more than 25 millivolts ac from ground to any one of the hard wired connections. Use strong copper clips for the testing connectors... Don't use any garbage clips like the ones that always come with a multimeter. Remember, you are testing FROM THE PLACE WHERE EACH WIRE IS TERMINATED/SCREWED -----and...TO THE MAIN GROUND.... I'll bet you will find high leakage on some of the wired connections...when you test from the wires to ground.... also... be carefull because you are doing this BEFORE any dangerous leakage problems are corrected....You "fix" the problem by super cleaning every single termination on every wire. Don't be shocked if you have to wire brush every SINGLE wired screw connector or bolt...If you still have problems... measure the voltage between the CASE/FRAME ON EVERYTHING....TO THE GROUND!!!!!!!!!!!!!!!!!!!!!!!!!

AND MAKE SURE THERE IS NO AC VOLTAGES LEAKING FROM FRAMES TO GROUND. BE SUPER CAREFULL ABOUT THIS BECAUSE MISTAKES CAN COOK YOUR HEART! NOW,

GO FIND THE LOOSE OR DIRTY TERMINATION SCREW AND CLEAN IT!!!!!!!!!!!!!!!!!!!!!!

OR, DRILL ANOTHER HOLE....DEEPER INTO THE CEMENT FLOOR.... AND HAMMER A

REALLY LONG COPPER ROD INTO THE HOLE! MERRY CHRISTMAS....!!!!!!!!!!!!!!!!!!!!

dv

I)nteresting post. Thanks.

If you have grounded the "neutral" to the earth terminal of the inverter then you must ground the inverter case to a good fixed earth. i.e. it must be equipotentially bonded. Failure to do so will leave you with the risk that the case will become live if you get a Live to Earth fault on your load or distribution system. If you are using this in a boat or RV then use the boat earth or the vehicle chassis.

As Simplemind says, it seems more likely that your load has an earth fault. Another possibility is that the equipment and or the inverter has some small EMI filter caps which will pull the unconnected earth of your equipment to midpoint of the supply.

The output of the inverter should be considered as an isolating transformer. They are invariably isolated from the dc supply.

European spec inverters do not normally earth either leg at the factory but some have switching options. US spec (marine) units must have one side grounded to comply with their regs.

This relates to the threads which have been on CR4 recently about earthing mobile generators.

Kind Regards

Chas