Please check my design.

[Brewman]

2000 ac watts / .85 conversion efficiency / 24 volts low cutoff + 20 dc amps / .8 fuse headroom = 147.549019608 fuse amps

So 150A it is.

 

[John Frum]

When it comes to the main fuse, it has to be able to handle the inverter and buck converter. As per the manual for the inverter it says 100A, the converter is 12V 40A out so that becomes 24V 20A in. Total is 120A, Should I up my main fuse to 150A or is 125A fine.

As for the PV circuit breakers, I should lower them from 40A to something like 20A. If the array is not big enough for really needing the breakers can I just leave the 40's as disconnects and if the array gets larger then resize them if needed?

The over current protection device is meant to protect the wire.
I would actually bump it up to 50 amps so that you have one less unique item on the BOM.

 

[Brewman]

I'm also going to take out the battery disconnect and just remove cable from fuse if needed to disconnect.

 

[Brewman]

Also I'm going to drop the PV wire to 10AWG, the roof of the trailer isn't big enough for any upgrade that would need 8AWG.

 

[Brewman]

Now to grounding, I plan on grounding the SCC, Inverter, converter, and PV to the Chassis. The negative buss bar will also connect to the chassis ground. The Transfer Switch will have the shore ground, inverter ground, and output ground bonded together but not connected to chassis ground as it should be bonded through the inverter.

 

[Brewman]

Most up to date pics of design and wiring. The picture of the item layout does not show the fuse between the pos buss and converter.

 

[Brewman]

Well if no one sees anymore issues I'll start putting it together tonight.

 

[svetz]

Well if no one sees anymore issues I'll start putting it together tonight.

On the DC domain, are you sure about 125 amp fuse on 4 awg THNN? (see note below)
From the Miguelez datasheet 90°C THHN THWN-2 AWG 4 has a maximum allowable ampacity of 95 amps.

Ditto the 50 amp breaker on 10 AWG (the datasheet says 30 amps).

Other notes (using drawing in #14, didn't see other updates with amps)

• 40 amp fuse may be high for 10 AWG wire on panels
• If the converter is 40 amps the 25 amp breaker is small for it and 10 AWG THNN may only be rated for 30 amps.
• Might want to add a shunt at some point, regretted immediately not having one in mine.
• Off the battery, is that still AWG 4 with a 150 amp breaker? Fine if your awg 4 can handle 150 amps.
• The max the SCC can put out is 40A, but the picture shows AWG 4 with a 50A. No technical problems there, but overbuilt.

Note: I'm not forgetting that UL says THNN can be 105°C when can be used for appliances. Just not 100% sure when it does and doesn't meet the spec.
Update: Found the spec, it's what it sounds like... for wiring on the inside of an appliance.

 

[Brewman]

The 10Awg from SCC to Buss bar should be 4awg, my mistake.

 

[Brewman]

On the converter, it's 40A out at 12V, wouldn't that be 20A in at 24V??

 

[Brewman]

My BMS is coming with two 8Awg wires, combined that's 5Awg, should I change that to no wires so I can add my own at the proper AWG?

 

[John Frum]

On the converter, it's 40A out at 12V, wouldn't that be 20A in at 24V??

Plus conversion factor.
40 amps /.9 conversion factor * .5 step down factor / .8 fuse headroom = 27.777777778 fuse amps

 

[svetz]

On the converter, it's 40A out at 12V, wouldn't that be 20A in at 24V??

Ah! Didn't know which side the 40 applied to!

 

[John Frum]

My BMS is coming with two 8Awg wires, combined that's 5Awg, should I change that to no wires so I can add my own at the proper AWG?

The bms is only rated for 100 amps.
I

 

[Brewman]

Plus conversion factor.
40 amps /.9 conversion factor * .5 step down factor / .8 fuse headroom = 27.777777778 fuse amps

Ok, 30A fuse. I was going by Wills setup.

 

[John Frum]

I'm not forgetting that UL says THNN can be 105°C when can be used for appliances. Just not 100% sure when it does and doesn't meet the spec.
Update: Found the spec, it's what it sounds like... for wiring on the inside of an appliance.

from the link "AWM is commonly used in a variety of applications such as general purpose wiring circuits, control circuits and internal wiring of appliances."
I suspect that is how the bms gets away with 2x 8awg.

 

[John Frum]

Ok, 30A fuse. I was going by Wills setup.

That is pushing it for 12 awg wire.

 

[Brewman]

That is pushing it for 12 awg wire.

It's what the converter comes with. 12 in 10 out.

 

[John Frum]

It's what the converter comes with. 12 in 10 out.

Yep and those converters are cheap and cheerful.
Check the insulation rating on the wires.... and then decide how much to de-rate for bullshit.
Fuse accordingly.

 

[John Frum]

Just gotta say that even if the insulation is rated for 105C and your use case falls within the envelope of appliance wiring....
...I really doubt any of us want your wires approaching the temperature of boiling water.