Inverter ac input/output breaker question

[KateC]

My inverter manual sucks. I can’t find the answer anywhere on Google, but I’m betting y’all will know.

I just got my 12v/3000w inverter. I’m looking through the manual and it says (I think) that the AC input, AC output, and the battery connections all need two pole breakers. I haven’t done much with circuit breakers, but I’ve only seen double breakers on 240v appliances like stoves and dryers. And don’t two pole breakers have two positive wires? Why would I need 2p breakers on all (or any) of those? There’s only terminals for a positive, negative, and ground.

Also, I’m only running one circuit off of this. Three 20A outlets that will never run at the same time. I doubt if I’ll ever really run more than two things at once.

I’m hella confused and I’ve attached the entire section from the manual for wiring up the AC.

I don’t think the other specifics of my system will matter too much for this, but I can give more info if needed.

 

[KateC]

Also, if anyone wants to translate the manual wording, that’d be great too. I’ve read it out loud slowly and it’s still not clicking.

 

[Bud Martin]

1) Can you provide more details about your inverter, I.E. user manual, spec?
2) There is not Positive or Negative in the AC system, only in DC system. Circuit breaker for DC has to be DC breaker (it has arc suppression) made to DC.
3) Are you in the US using US electrical system? In the US, the 120VAC with Line, Neutral, and Ground you only need to have breaker on the Line side.
4) The output of your inverter may not have Neutral bonded to Safety Ground so may be that is why it shows dual breaker, but at this point we have no idea of what kind of inverter you have.

 

[KateC]

1) Can you provide more details about your inverter, I.E. user manual, spec?
2) There is not Positive or Negative in the AC system, only in DC system. Circuit breaker for DC has to be DC breaker (it has arc suppression) made to DC.
3) Are you in the US using US electrical system? In the US, the 120VAC with Line, Neutral, and Ground you only need to have breaker on the Line side.
4) The output of your inverter may not have Neutral bonded to Safety Ground so may be that is why it shows dual breaker, but at this point we have no idea of what kind of inverter you have.

Oh, I did forget the inverter specs. Oops.

It’s an Ampinvt 12v 3000w inverter. I’ve attached the specs this time. Also, the manual is on their website https://www.ampinvt.com/index.php?id=2280

2. I meant line whenever I said positive in the original post.

3. Yes, I’m in the US. It’s a Chinese inverter, so I’m guessing other countries are different and maybe that’s what it’s for ??‍

4. Maybe. I didn’t see it anywhere in the manual or online about whether it’s grounded or not. Is there a way to find out?

 

[Browneye]

It's an 'inverter-charger' serving both functions. So the input is from where you connect it for AC power if you're going to use the charging function, and that would have a breaker - at home, an RV park, a generator, etc. If you only want to use it as an inverter - 12V to 120V - you don't need the 120V input side.

If you're connecting your AC loads via the outlet receptacles on the unit, you don't need a downstream breaker for that either. If you're going to hardwire into an existing system for 120V then it would go through an appropriate circuit breaker.

An inverter that size has the potential to draw a LOT of current from 12V, so appropriate wire gauge and fusing is required. And you need a sufficient battery pack and BMS to output that kind of energy, and then a way to recharge it.

What are you planning to run off a 3kW inverter?

 

[KateC]

It's an 'inverter-charger' serving both functions. So the input is from where you connect it for AC power if you're going to use the charging function, and that would have a breaker - at home, an RV park, a generator, etc. If you only want to use it as an inverter - 12V to 120V - you don't need the 120V input side.

I’m using it for both

If you're connecting your AC loads via the outlet receptacles on the unit, you don't need a downstream breaker for that either. If you're going to hardwire into an existing system for 120V then it would go through an appropriate circuit breaker.

There are no outlets on it. It’s hardwired only. And yeah, I was adding a circuit breaker, but was confused about the need for a 2p breaker. I emailed the company, but no coherent response from them (shocker, I know).

I’m assuming that the neutral isn’t bonded to ground by their response, but is there a way to check that? If it isn’t, that’s something that should happen in the circuit breaker panel, right? Mine is wired as a sub panel, but could I just run a wire from the neutral bus to the ground?

An inverter that size has the potential to draw a LOT of current from 12V, so appropriate wire gauge and fusing is required. And you need a sufficient battery pack and BMS to output that kind of energy, and then a way to recharge it.

I have a 280ah battery with 250a bms. 4/0 wire and 350a fuse. Does that sound right? As far as charging the battery, I have 200w solar panel on the roof, plus a portable 200w panel, shore power, and dc-dc charger from starter battery.

What are you planning to run off a 3kW inverter?

Honestly, it’s probably oversized for what I need it for right now, but I didn’t want to go bigger later and have to resize any wires or anything. It’ll mainly be some kitchen appliances—instant pot, maybe an induction cooktop, but no microwave. I do live in Georgia so I want to see how summer is with just the fan (probably miserable) and possibly look into 12v air conditioners later on.

 

[Browneye]

4/0 wire sounds beefy. That will surely carry a the load. Fuse should be sized 125% of your load current.

But I'm confused about the 2-pole breakers in the wiring diagram. Perhaps one of the resident experts will happen along and clear this up.

Some inverters have a built in ATS - automatic transfer switch - so there's the input AC and output AC, the unit automatically senses and switches. This is for wiring into an existing panel or branch panel. I understand passthrough on the whole panel, but not for an individual circuit, like a bank of receptacles.

Sorry, I'm not understanding it either.