[NickyFrank]

Hey Guys,

In the middle of my first build and have recently finished my electrical diagram. I would love some feedback on the drawing before buying all the cable and lugs. I worked really hard on the drawing, making it look good with pictures of all electrical equipment & loads, as well as including descriptions of what pieces of equipment is capable of.

Mainly concerned with my ground cables that connect to the chassis - I have 3 of them. One from DC negative bus bar, one from the ground lug on my Victron multi plus 3000w inverter, and one from my AC Breaker box. (please take a look at my drawing to get a better idea of my whole system along with the ground cables).

I'm concerned about having DC ground wires connected to the van chassis along with AC ground wires... is this ok?

If there is anything else you find concerning in the diagram please let me know ASAP as I currently feel confident with this drawing and am going to move forward following this plan very soon.

Thanks!

 

[ferall]

Everything looks reasonable, though charging at 30A off the alternator seems kind of slow for that size of battery.

I wouldn't use that particular 40 amp in-line fuse holder that you have pictured coming off the starter battery, I had one fail, luckily nothing caught fire but it did melt. Look for something like these midi fuse blocks, the only thing that can fail are your cable terminations as these are just an insulated block with two terminals.

https://www.etrailer.com/Accessories-and-Parts/Redarc/331-FK60.html?feed=npn&gclid=Cj0KCQjwufn8BRCwARIsAKzP697DJqEa81XpzLa_r3xX1PdT-29LaRZUc1qyUeZwu7TCypFf9IQA2E8aAh5oEALw_wcB

The chassis grounds are for safety not for carrying the return current back to the battery I'm not sure that you need 4/0 wire for them. I'm sure Victron can provide guidance if their manuals aren't clear to you.

 

[NickyFrank]

Thanks for the reply and looking at my system. I will defiantly upgrade to better fuses of the 40 amp connections!

I know current wont run on the ground cables unless there is a fault in my system... but it just feels wrong having DC and AC electrical wires touch and get mounted to the same chassis grounding bolt. I did try looking it up online and of course got mixed opinions. I did also read that your ground cable can be a bit smaller then the largest cable in your system, but just went with 4/0 as i will already be buying it.

30amp is probably a little low for a 6kw battery but I figured it would be supplemented with almost another 30amps from my solar during the day. I could always add another 30amp Victron dc-dc charge controller in parallel in the future... but I would defiantly need to up the size of cable! Might be better to plan for that now and run larger cable right off the batt, eh?

 

[Somebodyelse]

Do not ground your service panel/fuse box to the chassis. You have a ground loop in your drawing by doing so. This does end up with the possibility of the ground wire carrying current.

AC systems should be grounded in exactly 1 place. Your inverter/charger has a transfer switch. Allow it to provide the internal 'ground' or bond and ground at the actual service panel for utility (shore) use.

The ground wire coming from the case of the inverter equalizes the potential of the metal body with the rest of the van to prevent sparking and shock.

 

[NickyFrank]

Do not ground your service panel/fuse box to the chassis. You have a ground loop in your drawing by doing so. This does end up with the possibility of the ground wire carrying current.

AC systems should be grounded in exactly 1 place. Your inverter/charger has a transfer switch. Allow it to provide the internal 'ground' or bond and ground at the actual service panel for utility (shore) use.

The ground wire coming from the case of the inverter equalizes the potential of the metal body with the rest of the van to prevent sparking and shock.

Thank you so much for this valuable info! Just to clarify, I only need TWO DC chassis ground cables - One from my main negative bus bar, and one from my inverter? Then I take the AC ground from the AC fuse panel to my inverters AC output?

Simply put: I just delete the green 3' 8awg ground cable from my drawing (the one that goes from the AC fuse panel to the chassis ground)

 

[Somebodyelse]

Correct. Ground wire for ac fuse panel comes from the inverter. Inverter case and busbar ground to chassis. Everything else looks right.

 

[NickyFrank]

Correct. Ground wire for ac fuse panel comes from the inverter. Inverter case and busbar ground to chassis. Everything else looks right.

THIS was the answer I was looking for! I was questioning that cable for a few days now... Glad to know my suspicion was correct.

I will attach an updated version of my drawing for anyone interested tonight... I hope this will be the final revision!

 

[el Jefe]

THIS was the answer I was looking for! I was questioning that cable for a few days now... Glad to know my suspicion was correct.

I will attach an updated version of my drawing for anyone interested tonight... I hope this will be the final revision!

Someone may want to chime in on the scenario of a generator being the shore power source in lieu of a typical rv park pedestal.

 

[NickyFrank]

Someone may want to chime in on the scenario of a generator being the shore power source in lieu of a typical rv park pedestal.

I never plan to use a generator... seems silly with all the solar and alternator charging... but what would be the concern?

 

[ferall]

30amp is probably a little low for a 6kw battery but I figured it would be supplemented with almost another 30amps from my solar during the day. I could always add another 30amp Victron dc-dc charge controller in parallel in the future... but I would defiantly need to up the size of cable! Might be better to plan for that now and run larger cable right off the batt, eh?

It's a good size battery bank so on one hand you may not need to charge it fully everyday but if you go 3-4 days without good sun you might find yourself wishing you had more charging capacity from your alternator.

 

[Somebodyelse]

Fwiw, a normal generator will also have a false internal 'ground' (unless an actual ground rod is attached, but no one does that). Dedicated backup generators will often be set up to use the full true ground of the system they are backing up, but most generators are considered 'portable' and designed to be used independently. If used in lieu of pedestal shore power, the transfer switch will move the ground neutral bond to the generator.

As long as your Inverter/charger has the internal transfer switch, it's plug and play. Otherwise, you need a independent transfer switch in either case. You still never want an ac system grounded in more than one spot.

 

[el Jefe]

Fwiw, a normal generator will also have a false internal 'ground' (unless an actual ground rod is attached, but no one does that). Dedicated backup generators will often be set up to use the full true ground of the system they are backing up, but most generators are considered 'portable' and designed to be used independently. If used in lieu of pedestal shore power, the transfer switch will move the ground neutral bond to the generator.

As long as your Inverter/charger has the internal transfer switch, it's plug and play. Otherwise, you need a independent transfer switch in either case. You still never want an ac system grounded in more than one spot.

Great addition to this discussion.

 

[el Jefe]

I never plan to use a generator... seems silly with all the solar and alternator charging... but what would be the concern?

Others may incorporate a generator. You may not and that is fine. Many of us have more advanced systems. This is important for clarity for those folks.