I'm looking at a couple of options for a line side tap and each has complications. I'd like to get views on the best way.
I have two SB7000 inverters feeding a combiner 100A load center with 40A breakers from each SB7000US ( max 34A output) feeding the load center bus and a 80A output breaker to a Square D 223 RB fused ( RK5 - 80A) which will feed my line tap. The RK5 fuses provide service panel level protection as they are tied directly to the meter line side bypassing and before my 200A Square D Combo CSED mains.
I have two basic options.
My Square D Combo has spare lugs on the meter service side into which I can simply insert and set my 2 #4AWG hot wires. A spare neutral lug is also available also on the utility side of the panel where the neutral can easily be set screwed in. The ground can be set to the service side ground bar.
This sounds very clean and as though Square D left spare lugs for each of my line side taps right on the meter lugs and neutral bar. Sounds fabulous but I must enter and punch access into the utility - PG&E compartment in order to access the ideal spare lugs. I have been told its difficult to get permission to enter and wire inside the PG&E compartment. Is this true? If not for punching the access holes and getting permission to make the modifications, its ideal.
There are no larger bus bars for my model above 200A and modifying that would violate UL. Square D did not recommend it and said PG&E was difficult.
The other strategy is to tap into the four #4 AWG wires Square D uses to carry power from the utility side meter lugs to the four ( 2 pairs) main disconnect breakers. I can either remove the wires from the mains and pull into a small splice box where I splice the line tap #4 AWG wire pair and the four #4AWG wires returning to the mains set screw ports. Basically I'm breaking into and taping the wires on the line side before they hit my mains.
I can also replace the existing Square D #4AWG wires with slightly longer ( 10" to maybe 18") and replace the existing wires and run them into a splice box through a waterproof port and run through a block that has 3 holes and set screws. I run the two = hot wires through two holes and splice my #4AWG with the third port and set screw. That way the wires are unbroken between the meter and mains but I need to replace the shorter wires.
If I use the existing wires from the meter to mains, they won't reach into a small splice box and back. That keeps me out of the utility compartment but the wires from the meter to mains are also spliced to make up the longer run back through the punched port to the mains. Then my line tap connects to the same spli8ce block pairs and also run through a port out into the main service compartment and then out to my disconnect ( about 10 ft.).
So one option is very nice but has the PG&E policy and approval road block. The other means I hang a small splice box just outside the service compartment near the mains and use watertight ports to run 4 + 4 + 2 #4AWG wires. This version has the "use the existing wires and splice) or ( swap to 4 longer meter<-> main wires and just pass through the splice block).
If I am using THWN-2 #4 AWG wire for the tap and the inverters maximum is 68A but the panel breaker is 80A as i8s the RK5 fuse, is there any problem with #4AWG in this application when its in conduit ( 3 wires + ground). The #4 AWG THWN-2 has a 95A at 90 degree and 85A at 75 degrees both of which exceed the 80A breakers. Is #4 acceptable give the continuous will be 68A or less and the 80A breaker and 80A fuse will prohibit more than 80A under fault conditions.
Does that make sense