Negative wires when grounding to chassis

[pekka8]

Why do you need to run separate long negative wires around the van for DC system if you connect negative to chassis, along with equipment grounds? Why not just connect negatives to nearest chassis point or equipment ground point?

 

[12VoltInstalls]

Your direct cable is clean dependable power and copper wire is low resistance. A vehicle chassis is a poor conductor and subject to corrosion and other failures. Just bad practice.

I can’t tell you how many utility trailers, boats, and campers I’ve chased electrical problems for.

A proper independent ground cabling system almost never has issues and they’re easy to locate if they do.

Chassis-common ground issues can be so elusive and time consuming. And frequent.

Clean home-run grounds are safe and durable.

 

[pekka8]

Your direct cable is clean dependable power and copper wire is low resistance. A vehicle chassis is a poor conductor and subject to corrosion and other failures. Just bad practice.

I can’t tell you how many utility trailers, boats, and campers I’ve chased electrical problems for.

A proper independent ground cabling system almost never has issues and they’re easy to locate if they do.

Chassis-common ground issues can be so elusive and time consuming. And frequent.

Clean home-run grounds are safe and durable.

Makes sense. What about grounding, you can use one common wire for equipment ground and negative for long runs?

 

[12VoltInstalls]

Makes sense. What about grounding, you can use one common wire for equipment ground and negative for long runs?

Yes. No. Sortof. Technically you would want the ‘equipment ground’ to equal or exceed the sum loads it might see and not be the same wire as neg(-) in a 12V system. 120VAC same rule applies but is best a discriminated home run to the common point.

But what equipment are you grounding? 12VDC? 120VAC?

Either way you want it to be there to cause whatever circuit interrupt to open in a fault.

I have my 2000W psw inverter ‘equipment ground’ home-runned to the neg(-) busbar. They only provide and specify a tiny screw for that, while the inverter batt neg(-) is 2/0
I think they want to dissipate leak/stray as the 10ga wire I used is nothing compared to 2/0. The current SCC does not have a separate ground provision but neg(-) is zero ohms to the case. I may add a separate ground to that.
The “alternate system” is a 1012-LV-MK that is equipment grounded back to busbars.
You just need proper over current devices.

 

[pekka8]

Yes. No. Sortof. Technically you would want the ‘equipment ground’ to equal or exceed the sum loads it might see and not be the same wire as neg(-) in a 12V system. 120VAC same rule applies but is best a discriminated home run to the common point.

But what equipment are you grounding? 12VDC? 120VAC?

Either way you want it to be there to cause whatever circuit interrupt to open in a fault.

I have my 2000W psw inverter ‘equipment ground’ home-runned to the neg(-) busbar. They only provide and specify a tiny screw for that, while the inverter batt neg(-) is 2/0
I think they want to dissipate leak/stray as the 10ga wire I used is nothing compared to 2/0. The current SCC does not have a separate ground provision but neg(-) is zero ohms to the case. I may add a separate ground to that.
The “alternate system” is a 1012-LV-MK that is equipment grounded back to busbars.
You just need proper over current devices.

I'm talking about the 12V wires. Although they are usually quite close to each other, maybe alternator charger being exception.

 

[12VoltInstalls]

I'm talking about the 12V wires. Although they are usually quite close to each other, maybe alternator charger being exception.

I have run separate “equipment grounds” to the busbar location. “Remote” 12V devices like lights, cell signal booster, water pump are ‘case grounded’ internally to neg(-) so no need anyways.

 

[pekka8]

I have run separate “equipment grounds” to the busbar location. “Remote” 12V devices like lights, cell signal booster, water pump are ‘case grounded’ internally to neg(-) so no need anyways.

That's a good point that some devices have internal grounds.