Positive Ground PWM CC

windylion

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Feb 6, 2018
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Hello all!

Positive grounding.

I did a search for a thread on this topic but was unsuccessful. I've also looked for it in other forums. It gets talked about usually in reference to older cars, tractors, and tele communications.

I'm trying to wrap my head around what positive ground is vs. negative grounding. Current doesn't care which pole is which no? If you fuse/switch the energized lead and keep all grounds common, does it matter what you are calling each wire?My thinking positive grounding only becomes an "issue" when you have some things grounded to positive, and some to negative. Then, you have energized your ground.

I'm building a tiny house which will have 24v & 12v DC and 120v AC from an inverter and shore power. Would I run in any complications grounding "positive ground" and "negative ground" components like an inverter, 24v battery, and charge controller with 120v also common with the same ground system?

The charge controller I'm looking at is Epever LS3024B.

Any assistance would be much appreciated!
 
We aren't really talking about grounding here, only your 120Vac mains connections will hopefully be grounded. As a de-facto standard, most circuits use a common negative as the return path for all currents. However, EPEver/EPSolar seem to like common positive connections on their devices. Don't know if others do that as well, but it definitely is a thing at EPEver/EPSolar. I can't think of any implications that this might have and any issues occuring because of that. When you are connecting a common negative device to the common positive charge controller you watch for polarity anyway and the voltage between positive and negative is still the system voltage at this moment, even though it's commonly joined on the positive side in the inverter.
 
Most inverters and like equipment will ground on the Negative side. If you are curious as to which one is grounded where, take a Multi-Meter and set it to Ohms/Resistance and probe from Pos to Chassis, and then from Neg to Chassis. This will tell you which way your device is grounded.
Positive grounding was mostly in older DC setups as you mentioned. There are rarely any devices that use that practice anymore. For what ever the reason, and I'm not an EE, negative grounding is far more safer and generates a lot less noise than positive grounding.
I'm sure if you google search "negative grounding vs positive grounding" you will get many answers.
 
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