Case Ground Question

Nov 18, 2010
2,441
Catalina 310 Hingham, MA
I am getting ready to install my solar controller and something just occured to me. I was about to order wire to run from the solar controller to the ground bus at the engine as a case ground. But I am installing my solar controller next to my battery charger. I already have a case ground running from the charger to the ground bus. The case ground for the charger is a 6 AWG wire and recommended size for the controller is 10 AWG. Is there a downside to just jumping from the solar controller to the battery charger for the case ground?

Thanks,

Jesse
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
If by case you mean the ground that keeps the controller case at 0 volts potential then no there should not be a problem as a case ground does not normally carry current. Now if you are talking the current carrying return ground then you have to make sure the total current that wire will ever see does not exceed its capacity. Given that the solar and charger will probably never be on at the same time then I'd say you should be OK if the charger has more capability than the solar panels.
 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Just to be clear, I am not talking about the negative run of the 12 volt wiring.

I have attached the page from the solar charge controller manual where grounding is discussed and a photo of my battery charger with the case ground attached.

I am thinking about just running a wire from the lug on the solar charge controller shown in the manual to the case ground on the battery charger. The solar charge controller is going to be mounted right next to the battery charger.

Thanks,

Jesse
 

Attachments

Jun 28, 2005
440
Hunter H33 2004 Mumford Cove,CT & Block Island
Just to be clear, I am not talking about the negative run of the 12 volt wiring.

I have attached the page from the solar charge controller manual where grounding is discussed and a photo of my battery charger with the case ground attached.

I am thinking about just running a wire from the lug on the solar charge controller shown in the manual to the case ground on the battery charger. The solar charge controller is going to be mounted right next to the battery charger.

Thanks,

Jesse
Each and every case ground should be its own entity for EMI and safety.

Each should be returned to the negative buss bar individually.
 
Nov 14, 2013
200
Catalina 50 Seattle
You could probably get away with jumping the case ground to the main charger's, but it's not to code. 10 AWG wire isn't terribly expensive or difficult to work with, I'd bite the bullet and do it right.
 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Each and every case ground should be its own entity for EMI and safety.

Each should be returned to the negative buss bar individually.
So your response got me thinking there has to be something in the ABYC standards.

Attached is a page from the ABYC Standards. If I am reading this right, I could add a DC grounding bus and connect both the solar controller and the battery charger to that bus.

Does this make sense or am I off somewhere?

Thanks,

Jesse
 

Attachments

Jun 28, 2005
440
Hunter H33 2004 Mumford Cove,CT & Block Island
So your response got me thinking there has to be something in the ABYC standards.

Attached is a page from the ABYC Standards. If I am reading this right, I could add a DC grounding bus and connect both the solar controller and the battery charger to that bus.

Does this make sense or am I off somewhere?

Thanks,

Jesse
Yes, as long as it is an extension of the DC negative bus.