Wiring Size Issues

Hello All
I just purchased and awaiting the arrival of a new 2000 Watt Pure Sinewave inverter. My PC currently has the Xantrex 1800 Watt Modified Sign Wave Inverter. I started to investigate the wire sizing to the Xantrex and just realized it is undersized from the factory. It should be 2/0 wire with a 250 amp fuse and its 1/0 wire with 400 amp fuse (2ea 200 amp in parallel) .  Also to add to this they took a 6 gauge wire from the positive side of the inverter to power the 12 Volt power distribution panel with no fuse protection. There should have been a 50 amp fuse/circuit breaker at the inverter protecting the 6 gauge wire to the 12 Volt distribution panel. Then the 2 gauge wire leading to the HWH levelers comes off the paralleled 200 amp fuses (400 amps) so its not protected either, it should also be a 120 amp fuse. Also the 12 volt rotary disconnect switch located at the door is rated only for 300 amps, and it also is being protected by 400 amps (2 ea paralleled 200 amp fuses).

I should have caught this earlier when I worked on the wiring that was originally located behind the batteries. I went and wired it back to the way PC installed it which is not the way it should have been done, as per manufacturer instructions. If I am incorrect please let me know...

I am including a picture of the inverter with the 6 gauge wire leading to the 12 volt power distribution panel, picture of the original wiring configuration behind the batteries and the wiring change I made which is still not correct.

The correct wiring should have been a 250Amp fuse with 2/0 wire to the inverter (this means power and ground wires also at the battery), a 120 amp fuse to the HWH levelers, and a 50 amp fuse/circuit breaker at the power inverter 6 gauge wire leading to the power distribution panel. 

The reason I wanted to up grade the inverter is so I could run the microwave, I tried it with the Xantrex 1800 , it struggled and you could hear the microwave change tone as it also struggled. I wonder how much of an issue under sizing of the wire may have affected the microwave operation. I figured that 2000 watt pure sinewave inverter should run the microwave as long as I upgrade the wire to the proper size of 3/0 as per manufacturer of the new inverter.

You dont mention the length of the runs, but I am confident you have the resources to get this correct.       

I am including a picture of the inverter with the 2 gauge wire leading to the 12 volt power distribution panel,

Please... thats pretty cheezy... you believe this to be as it was delivered? If so, OW. 

Not sure what 12v distribution they used on 2017 models, but on my 2015 model with  a Parallax 5300 series, the 12v panel has 2 30amp fuses next to the panel to protect the 12v input, plus, it's rated at 55 amps total for the converter, charger so #2 stranded copper should be fine as it's rated capacity at room temperature is 95 amps.

Don

Hello Don
Thanks for your reply, it made me find an error.  The wire from the positive side of the inverter to the 12 volt power distribution panel is 6 AWG so 50 amps max.
You are correct there are 2ea 30 amp fuses located on the converter section these are for reverse polarity protection and over current, just for the converter.  These however have no bearing on the 6 gauge wire from the inverter to the 12 volt power distribution panel. This wire is used just to get battery power to the 12 volt distribution panel, and also serves as a path for the converter to charge the battery. So if you had a short in the distribution panel the 6 gauge wire would burn.  This is why I am adding a 50 amp circuit breaker at the inverter for the 6 gauge wire. I have the 5300 as well. Speaking of the 5300 are you aware that the converter is only a single stage charger? This is very hard on lead acid/AGM batteries and is often responsible for shortened life cycle of the batteries. I am installing a WFCO WF-9855-LIS converter which is 3 stage and also is capable of charging lithium Ion batteries as well. I don't currently use the 5300 converter as I don't want is to overcharge my new 8D AGM battery, and I just removed it yesterday. I am attaching a picture of it laying on my work bench you can see the 2es 30 amp fuses. I use strictly the solar system which also has 3 stage charging. i also included a picture of the 5300 how it looks now since i removed the converter. You can see the red 6 gauge wire attached to the 12 volt power distribution panel which runs back to the positive side of the inverter. You can also see between the cracks and the converter is not sitting behind the 12 volt power distribution panel anymore.

This however is only one issue with the wiring, like I said previously the 2ea 200 amp ANL fuses in parallel (400 amp) far exceed the amperage rating for the 1/0 wire.  Plus the wire to the inverter is under sized which reduces its efficiency as well. Then there is the issue of the 2 gauge wire to the levelers that is also not protected as it comes off of the same  400 amp circuit, when it should be protected by a 120 amp fuse. i guess we look at things differently.

That's typical for automotive, just as an example, a starter on a Ford V-10 can draw upwards of 500 amps and yet the wiring is typically 2/0 wire which is rated (stranded copper) at 125 amps.  Obviously no fuses on the cable from the battery to the starter.   I can only guess at the engineering logic, but presume the wire rating is continuous amperage whereas starters and the like are short term amperage draws.  You are correct, we see things differently.   That's fine, different strokes for different folks.  Doesn't make either view right or wrong, just different.

Don

Hello Don
You are correct about the wiring in a starting circuit. The issue in my mind is that the 12 volt circuit to the 12 volt distribution panel is in use 24/7 unless you secure the battery power at the cutoff switch as opposed to the starting circuit. RV's are in a state of code requirements between home and automotive, they should error on the more stringent requirements as they are mobile and experience more stresses than a brick and mortar home.

Here is my start at fixing the wiring issues.
1) removed the buss bar that paralleled the 2ea 200 amp ANL fuses, and removed the fuse's
2) installed 300 amp ANL fuse to inverter circuit
3) installed 120 amp ANL fuse to levelers
4) installed 50 amp circuit breaker near inverter

I still need to install the new inverter and run 3/0 wiring for it. Not looking forward to working with the 3/0 cable as it is much larger and stiffer to work with.

There's more than the starter circuit, look at your alternator output wire.  I didn't look at the gauge but seems a #4 or #6 wire yet the alternator can output ~150 amps.

But yes, keeping your comfort level up is always a good thing.

I keep a high quality CB installed for comfort because there are areas we go with zero cell signal... Even with a serious cell booster also installed.  Those 2 raise my comfort level, I am sure others may think they're a waste of $

It's all good.

Don

Oh well