I am upgrading to a 400 Amp service in Washington State. My power company is Mason County PUD 1. The AHJ is Washington State L&I. The panel I'm planning on using is the Siemens MC0816B1400RLTM. What size/type wires should I use between the mast head and the line side of the meter? How do I connect these wires to the power company's service wires? This is max 14' run (10' of mast, 2' on either end).
The Siemens spec sheet says the max wire on the line side of the meter is (1)600kcmil OR (2)350kcmil for the two hots and (1) 500kcmil OR (2) 250kcmil on the neutral. In their meter requirements, the power company says "Lugs must accept 350 MCM aluminum wire." They say this is the largest wire they carry. I just confirmed with them that they will have six service wires coming to me from the power pole.
I haven't been able to find a consistent answer to what wire I need. I'm thinking AL XHHW-2.
If there is some way I can join the power company's parallel lines into one, I think I would use 600 MCM for hot and 500 MCM for neutral. According to https://www.wireandcableyourway.com/xhhw-2/, 600 MCM is 385 amps at 90 C. Assuming I never use the full 400 Amps, does this work? What gizmo would I use to bond each of the two wires from the power company with my one wire that leads to the mast head?
Or should I continue their parallel runs through the mast all the way to the meter? Again sticking with AL XHHW-2, the same place says 4/0 is 205 Amps at 90 C. So, in parallel, does that make it 410 Amps? Is that sufficient? Or is it close enough that I'd be better off going with parallel 250 MCM? Again, what gizmo do I use to bond each of the six wires from the power company to one of my six going into my mast?
I had been planning on a 3" dia. mast. Is that sufficient? More than sufficient?