Wire size - Inverter To AC Panel

[Meathead]

Ok. I have a blue seas ac panel. From that I have Ancor 12/3 stranded and tinned wire running to outlets and appliances. I am planning to use a 10/3 extension cord to go from my inverter to the panel. Is this ok? What is best? Thanks in advance!

 

[ermracing]

We used 8/3 but are only using the black, neutral and ground right now. The red is in reserve in case we upgrade our shore power and 110v box later on.

 

[PNW_Steve]

What is the capacity of the inverter?

 

[Meathead]

My inverter is 3000w. This is way more than I need. I just know my better half will find a way to use electric cooktop and washer etc at the same time and call me when I’m fishing [emoji43].

I just figure if 12ga is normal then the main line will have to be bigger?

 

[Danjo-SKO]

Just to preface this; I have never wired a bus. I’ve chased wires in a commercially built RV and got a taste of the laughably poor workmanship that goes into them. I’ve also engineered and rewired an entire house, so take my advice as you will. In other words, I’m not a licensed electrician, but I do have some experience with AC current installations.

You will want to consult an NEC code book.

The wire you use is a function of the circuit’s intended maximum ampacity, the type of wire insulation, the size of the raceway, the number of conductors in the raceway, and the ambient temperature.

I’m doing this based on NEC table 310.15((16)
That I found on the Internet, so you’ll want to confirm based on current code.

So assuming you are using non-metallic (AKA Romex)

And assuming 3000 W @ 120 V = 25 A + 20% (don’t exceed more than 80% of ampacity) = 30 A

And ambient temperature not exceeding 90 degrees C

And assuming number of conductors is 2 or 3

The wire size would be 10 gauge

http://marketing3.southwire.com/PubImg/2534e3165836463ea44839d9ef6cd5e0.pdf

 

[ermracing]

We are running a 3000w inverter as well with 4, 20 amp double breakers. We also think it's a little oversized for our initial needs. I had a friend (cert electrician) help me connect the inverter, batteries and breaker box and he told me to use the 8/3 wire.

 

[PNW_Steve]

Just to preface this; I have never wired a bus. I’ve chased wires in a commercially built RV and got a taste of the laughably poor workmanship that goes into them. I’ve also engineered and rewired an entire house, so take my advice as you will. In other words, I’m not a licensed electrician, but I do have some experience with AC current installations.

You will want to consult an NEC code book.

The wire you use is a function of the circuit’s intended maximum ampacity, the type of wire insulation, the size of the raceway, the number of conductors in the raceway, and the ambient temperature.

I’m doing this based on NEC table 310.15((16)
That I found on the Internet, so you’ll want to confirm based on current code.

So assuming you are using non-metallic (AKA Romex)

And assuming 3000 W @ 120 V = 25 A + 20% (don’t exceed more than 80% of ampacity) = 30 A

And ambient temperature not exceeding 90 degrees C

And assuming number of conductors is 2 or 3

The wire size would be 10 gauge

http://marketing3.southwire.com/PubImg/2534e3165836463ea44839d9ef6cd5e0.pdf

Well said!

 

[TheHubbardBus]

Ditto what Danjo said. Both the NEC and your inverter manufacturers documentation are good places to seek out the answer to your question. What other people did, with other equipment (right or wrong) is irrelevant. There's no 'normal'... it's entirely dependent on your max amp draw, fusing (to prevent that from being exceeded), environment, length of wire run, and wire type/insulation.

 

[Meathead]

Thanks All !!