Looks like hot and neutral are reversed in the new inverter...

softdown · October 2016

Using an Ideal line checker, I got indicator lights showing that the hot and neutral are reversed at the end of the newest line. Switched them back and forth no less than three times!

Then I plugged the line checker into the outputs on the Cotek 1500 watt PSW inverter. Got the same reading.....hot and neutral are reversed.

It is amazingly easy for assembly line mistakes to be made. A perfect high tech product may be the exception, not the rule.

1) I think I know why I got such a "good buy" on a few of these inverters.

2) It doesn't seem to effect normal operations. Or does it? This concern is the primary reason for this thread.

BB. · October 2016

In theory, all you need to do is reverse the Back and White wires going to the outlets (you should phase tape the "original wires" to keep everything straight.

Also, you may be able to go into the inverter's AC panel and simply move the ground bond to the white/neutral wiring (depends on what was done wrong in the inverter--But it should be easy to fix). Or, you can "cut the ground bond" in the inverter, and ground bond in your AC main panel.

-Bill

softdown · October 2016

BB. said:

In theory, all you need to do is reverse the Back and White wires going to the outlets (you should phase tape the "original wires" to keep everything straight.

Also, you may be able to go into the inverter's AC panel and simply move the ground bond to the white/neutral wiring (depends on what was done wrong in the inverter--But it should be easy to fix). Or, you can "cut the ground bond" in the inverter, and ground bond in your AC main panel.

-Bill

Is it also possible that the problem stems from a failure to properly ground the inverter? I thought the 1650 pound battery made a sufficient ground. I need to learn more about proper grounding. Funny considering how much wiring I have run in my life. A lot of pretty experienced folks tend to "poo-poo" the need for proper grounding. Perhaps the best thing about grounding is reduced shock hazard?

It seems the only problem with this reversed polarity is the increased shock hazard....which I have already experienced. Fortunately I have a high tolerance for shock....perhaps from being shocked a few dozen times. That comes from working with water and electricity all the time. Standing in some salt water may be the final shock however. Pure water isn't bad....saltwater is the worst for carrying electricity (that leaps from solid to solid).

This new solar array does not go to any AC main panel. This second string is dedicated to a couple freezers and refrigerators. It is still a work in progress with three separate PV strings using three charge controllers.

BB. · October 2016

Don't laugh off 120/240 VAC shocks... Today a 120 VAC hit will get you a doctor's visit and a 240+ VAC hit will get you an overnight stay in the hospital (electricians have died hours after a hit) with California OSHA (as I understand from a friend).

Grounding is the sum of many different issues (shock grounding, lightning grounding, the ability to trip a single breaker to ground/neutral vs needing paired breakers for floating systems, starting florescent tube fixtures, flame sensing on stove/water heater with spark ignition, etc.).

If you have "typical" TSW/PSW AC inverter--The AC output is isolated from the DC input. So, the "neutral bonding" is simply a connection from the "white wire" output of the transformer to the AC inverter chassis. What you do from there (typically ground the AC chassis to the ground rod/cold water pipe) finishes the AC grounding side.

On the DC grounding side, I like a 6 awg from battery negative bus to the same ground rod/cold water pipe.

If you have an MSW inverter (modified sine/square wave), the AC output should not be ground referenced White wire bonded to ground (will let magic smoke out of AC inverter)--Both wires are "hot" relative to the DC battery bus--And will show Neutral and Hot as "hot" relative to the DC battery bank ground (and how it looks to AC green wire ground and DC green wire ground connections.

-Bill

mcgivor · October 2016

Technically without grounding the inverter and one leg of the output you will never have a neutral, it is unlikely a manufacturer error .see arrachment

softdown · October 2016

mcgivor said:

Technically without grounding the inverter and one leg of the output you will never have a neutral, it is unlikely a manufacturer error .see arrachment

Thanks....that was my suspicion. I do not see a reason why the battery and inverter could not use the same ground rod though. The schematic shows them using separate ground rods.

mcgivor · October 2016

Same ground should be OK, the diagram is for graphical purposes, a common ground would probably be preferred as everything would be bonded to a common point.

softdown · October 2016

Grounding the battery and the inverter did not fix the problem. Wondering about an efficient way to ground an output leg. Grounding the inverter ought to have grounded the ground wire.

The vast majority of the people will simply use the inverter as is...many will ground it, others will not. The inverter has two 120 volt outlets. It supplies 120.3 volts at the end of an ~120' run with 12awg.

mcgivor · October 2016

What model is the inverter and if it is a US market unit, it should have a GFCI outlet.

softdown · November 2016

mcgivor said:

What model is the inverter and if it is a US market unit, it should have a GFCI outlet.

It is a Cotek 1500 watt PSW. They usually come with a GFCI....this one did not. Perhaps that is where a mistake was made. I have read of Cotek GFCI's buzzing in this model. Making me wonder about the quality of the pure sine wave. Modified sine wave inverters make a lot of GFCI's buzz. Not a loud buzz....but a buzz none the less.

It is also now possible that I reversed hot and neutral while trying to fix the problem.....three times.

JimHanus · June 14

Wondered if anyone else has found this to happen? I have a Vevor 2500w Inverter without an external ground lug. I opened the case to look for one and saw that the hot and neutral are reversed on one of the three outlets. This is by design (see attached) or how the circuit board was built. The orientation of the 3 outlets are the same externally. Is this OK? What are the dangers of leaving it like this?

Image: https://us.v-cdn.net/6024911/uploads/editor/vh/bln7t7p7ep3r.jpg

NANOcontrol · June 15

I had an inverter where the ground pin was connected to a 100k resistor and then to the case. Enough to drain off any capacitive leakage that might cause a tingle. But, not enough to damage the inverter if the device had a short to ground.

Recently got a triac speed control and it was switched and fused in the neutral. It also carried the ground to the output socket without grounding the metal case. The AC power cord had the international color code for indicating hot and neutral except that they were reversed. I'm pretty sure the Chinese company bought these defective cables because they were cheaper.

Looks like hot and neutral are reversed in the new inverter...

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