Negative ground proper setup

Question

question

reid-dyer asked Feb 29, '24

Negative ground proper setup

Hey everyone pretty new here. I've looked at other questions and can't seem to find the answer. 48 volt system, fixed structure. I have a 10kw nominal solar array, two 150/100 charge controllers, 3 quattro 48/5k/70 split phase setup (planned on 3 phase but somewhat led astray by my vendor so moving on), 3 kilovault Habs 7.5kw LiFePo batterys and a victron smart shunt. Also cerbo gx and digital dispaly. I know that grounding and bonding is a can of worms especially when you talk about lightening/static protection but for now this is only related to the suggested system installation and proper safe operation. I have a series of questions but I'll do one at a time to keep it flowing smooth. I can tell there are quite a few questions on the forum that are somewhat unanswered so I'm hoping this will help me and maybe a lot of others. I want to do what the experts say but also understand why

So..... Do i understand correctly that my negative main bus bar must be earth grounded to provide proper operation of my dc ground fault circuit breaker?

As I said I have several other questions on connection locations and wire sizes but I'd like to ask those based on this answer to create a simpler flow for understanding the how and the why. Thanks again.

Grounding

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Modifications Space

Node Red Space

Answer 1 · 2024-02-29T19:39:23Z

bartrs answered · Feb 29 at 07:39 PM

You will find this a very interesting 'book':
Victron Wiring Unlimited

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Answer 2 · 2024-02-29T21:05:42Z

reid-dyer answered · Feb 29 at 09:05 PM

Yeah man. I got it. Read it. Doesn't really answer the questions I have or at least I don't see it. I was hoping to get a series of simple answers for myself and everyone else as there seems to be a ton of people out there asking the same thing

.The grounding section of wiring unlimited doesn't have an example while using a shunt. That was one of my questions... is the grounding wire for the negative side of my system on the system side bus bar or battery side bus bar of the shunt or does it matter? Another question was that the manual says to size the chassis ground wires for each component according to the fuse size or basically the same size i fed the xomponent with, which doesnt make sense to me. I own an havc company and have compressors run at 20 amps on a 30 amp circuit but have a locked rotor of 90 amps but only a 14 guage ground wire. They short out and sometimes to ground and actually blow the whole house main 200 amp breaker but the 14 guage ground wire nor the 20 guage feed wire aren't hurt. I know that's ac voltage, so it is a different animal but still no explanation. With the dc voltage wouldn't a dead short cause a near instantaneous trip of the breaker amperage wise and the wire only sees the load for milliseconds. And wouldn't a minor short instantly blow the ground fault. And if I do have to run these massive ground wires then how big does my actual final ground wire going to my external earth ground rod have to be? Sorry I unloaded there. Maybe these answers are in the books somewhere but I didn't see them and certainly not coniguosly. By the way local code/inspection compliance is not an issue on this.

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

question