No Power At Panel

Need to see how your panel is set up? Do you have a rotary switch to select shore/gen or dual breakers with safety slide or some relay transfer switches.
Post pictures or the panel. What year boat ?

Don't get me wrong Eifeler, but if Pascal (or anyone else) is capable to solve the problem you are experiencing based only on your description and photo, then his telepathic skills are way better than even the best electrician!

Newer gen-sets have a breaker on the set itself. Did the installer not check this out?
Orlando or Sanford?

As Ralph suggested check the AC breaker on the generator itself

Then start at the panel. You said power is getting from the gen to the panel. How do you know? Have you checked for power at the wires coming into the panel from the gen behind the generator main breaker. It you have power on that side ofnthe breaker, check at the output and then check where the wires go from the breaker. They should go to the main buses.

Who installed the generator? They didnt test it???

They install a marine generator but are not marine electrician qualified?

Ok so your original post was misleading as you said “Power is getting from new genny to panel but panel is not happy”

so power is not getting to the panel.

breakers rarely get shorted. They trip for no reason, they get stuck, but rarely short out. Replace the breaker just in case. Cheap and easy. If that doesn’t solve it, inspect them wires coming from the gen, not just the two hits but neutral as well

If they look ok then you ll have to test. Disconnect the wires coming from the generator at the generator breaker in the panel. Insulate them to make sure they can’t touch anythjng

two options, nr 1 Make sure the breaker on the gen is off and start the gen then turn the breaker on the gen. If it trips, it means the wiring is shorted out. trace the wires and replace them if damaged

nr 2 safer… disconnect the wires at both breakers ( gen and panel) then using the continuity function on your meter check for continuity. If it beeps it means two of the wires are shorted. Test between every pair of wires, incl N and Ground.

Obviously, turn off shorepower before opening the back of the panel

Carbon trails develop inside transfer breakers as in your installation.
I have found this issue a couple of times before from opening and closing these breakers while under loads.
To a DVM, it would make strange readings.
While connected to shore, I have found this to have damaged running gen-sets.

There are different ways to config a gen-set. 240Vac, 230/115Vac, or just 115Vac are common.
More voltage options may be available pending the mfg or model of the sets electrical end.
Single or 3 phase may be another config option.
To a DVM, improper config would make strange readings.

Past these thoughts, it is a simple 4 cable hook up. Sometimes the colors of the cables can be confusing.
Usually Black, Red, White and Green. I have found a few times the ships wires to include 2 blacks, blue, yellow used also.
On my 44 year old Bertram, the factory used 2 reds, 2 whites. What ever was cheap during that build week in '78.
What ever the color, It takes a minute to confirm correct orientation between the gen-set and the panels transfer breaker.

Some gen-set installs did not have a breaker built in. A stand alone breaker box may have been installed between the gen-set and the breaker panel.
Cable colors may have changed here. On one customers boat, neutral and ground were found tied here causing some strange DVM readings.

So, I have to ask, how did the previous gen-set run? Making power?

If the gen is making correct power, what's the installer coming back for and talking to Phasor about? I thought your issue was after the gen and before the panel? Did your electrician ring out the main power wires from your gen to the panel?

Whoever did this has to be some kind of special stupid and should not be allowed to work on a boat or anything electrical. No it it not easy to miss. He should have felt the space with his fingers and realized there was a problem.

Glad to hear you got it resolved and it was a simple fix, even if difficult to troubleshoot. Appreciate you sharing so others can hopefully avoid the same situation.

Avoid the same shop of SFBs.

Holy smokes. Fender washers were the washers of choice here? Disappointed that no crow bars were available to assist the hold-down...