Please help me figure out this electrical box...

tons001 wrote: »

Should be but I am sure someone will correct me if I am wrong.

A = Combines the neutral/ground bars.
B/C = Neutral/ground bars
D = Service neutral in.

Ground and neutral bars are combined which is why is you measure hot to neutral you get 120vac and hot to ground you get 120vac. What you don't want is voltage between neutral and ground in any circuits. The only reason their are two bars (B & C) is to help keep your electrical box tidy.

tons001 wrote: »

So you are thinking his sub-panel box is missing a ground bar then? Out of curiosity, why would a sub panel have separate neutral and ground bars when in reality they are tied together anyways?

In this situation, it would seem that cupcake is treating the sub panel as his main panel. Could cupcake not just bond the case to the neutral bar?

BB. wrote: »

Oh boy... This gets difficult very quickly.

How is your Samlex grounded (chassis ground to battery negative? Battery Negative to ground rod?

The issue is that your Samlex has a very heavy set of DC +/- cables coming in from the battery with something like a 200+ amp fuse.

What you don't want is a DC side + to chassis short on the Samlex going through the 14 awg wire to the main panel, then to the ground rod and then back to the DC - bus on the battery bank.

My recommendation--If you use the N-G in the AC inverter. Ground with a heavy cable from the Samlex chassis back to the Battery Negative Bus (at least 6 awg cable). And run your single ground cable (again 6 AWG) from the Battery negative bus to the ground rod.

Only do your AC Panel ground rod if you don't use the N-G in the inverter.

This stuff is complicated.

-Bill

BB. wrote: »

You do not want the "straw" colored connection in the AC box at all... Just run it to the battery negative bus.

You can run EITHER a green wire from the AC inverter (same gauge as your AC hot/neutral) to the AC Box Ground Bus OR Run a cable from the battery negative (or even from the ground rod "single point ground" to the AC Box Ground Bus (6 AWG).

Do you have lightning in your area? Using the 6 AWG from the battery bus negative or the ground rod negative and Lightning arrestors would probably be a better idea.

Whether you call the battery bus negative as your single point ground or the "Master Ground Rod" is sort of semantics. Ideally, you want to make sure that the ground rod to battery negative bus is never "lifted" during normal servicing of the battery bank (i.e., if the battery bus negative is always solidly connected hunk of metal/copper--Vs just tying a grounding wire to the battery negative post which not a good plan).

White neutrals can go to either left or right neutral bus.

Depending on how "D" is attached, you may move it to the right for the inverter AC connection, or have to wrap the inverter neutral to the left with the large lug is, or simply use the small neutral bus hole(s) if the inverter cable it something that will fit (10, 12, or 14 AWG).

-Bill

BB. wrote: »

Yes--The current path for any short circuit 12 VDC power should be heavy cable (like 6 AWG minimum). Pretend that you get a short from 12v+ to inverter chassis. Trace the "return current" path and make sure that it goes through 6 awg wire (minimum).

-Bill

mike95490 wrote: »

one more thing, your box is designed for a "Split Phase" feed. The breakers plug into the 2 silvery interleaved buss bars in the middle. Phase A, and Phase B. Your inverter is single phase. So you will either have to only use half the breakers, or jumper the 2 buss bars together. (or maybe there is something I'm not seeing in the photos)

Jumpering the 2 buss bars together, will make a bizarre nightmare for the next person - use a weird color wire for the jumper

BB. wrote: »

With a split phase system (120/240 VAC) as in North America... The Black and Red wires are 120 VAC and 180 degrees out of phase. So you can have 2 "full power" 120 VAC branch circuits with just 3 wires plus ground (black+red+white+green). You can get (for example) 15 amps from black+white and 15 amps red+white--Or 15 amps of 240 VAC with Black+Red (or combination thereof).

With 120 VAC--You would run 120 VAC Black+White+Green for one 15 amp circuit. And a second Black+White+Green for a second 120 VAC circuit. So it takes 5-6 wires (2x black+white + 1-2 green grounds) for two 120 VAC circuits vs 4 wires (Red+Black+White+Green) for 2x120 VAC circuits on a split phase circuit.

So, you have to use a bit more copper wire, and, obviously, you cannot get "native" 240 VAC from a 120 VAC setup.

-Bill