Upvote:1
I'm guessing you used kiwi.com. Basically, they self-insure against the possibility you don't make this unpublished connection. If you miss, they are supposed to take care of you. There is a flight on United in the morning. I don't believe there are other red-eyes after the Norwegian flight, but without knowing which day you are leaving, it is impossible to tell.
Security will not be an issue. Getting to the Norwegian counter by 11:15 might be. If you could take your bag as a carry-on, you could check in for Norwegian by Internet.
Upvote:4
Unless something unusual happens you are fine.
The flight from SFO to EWR is a domestic flight. You can just walk out the plane, out of the security and to the baggage claim to get your bags. You can then just hop on the air train to terminal B and go over to the Norwegian check in. That really shouldn't take more than an hour.
Things are different if your incoming flight is severely delayed or they misplace your bags, but this can't be predicted. Since it's two tickets you assume the full risk of a missed connection. This may include having to buy a whole new same-day ticket from EWR to LON. While the risk is low, it's not zero and hence I personally budget a minimum of 4 hours for a two ticket connection. It really depends on your own personal risk tolerance.
If you happen to have booked this on KIWI and planning to rely on "connection guaranteed by Kiwi" policy, I strongly recommend reading the fine print. Kiwi does NOT guarantee to get you to your destination but the coverage is capped at the price of the flight that you miss (and there are plenty of loopholes for them to weasel out of that). This is very different from "connection guaranteed by airline", where the airline has full responsibility to deliver you to your final destination.