If the service-entrance conductors — the cable or wires between the utility point of attachment or the meter and the main — are still 100-amp or 150-amp equipment, they have to be part of a real 200-amp upgrade. Swapping the panel alone leaves the bottleneck in place, the same way a 100-amp meter socket does. Angi, updated 29 October 2026, quotes master electrician Salvatore Cutrona on this family of problems: a new 200-amp-rated panel does not help if the exterior wire and meter box remain 100- or 150-amp equipment. The meter-base page is the companion to this one.
Overhead masts, underground laterals, and the utility-owned drop or lateral each have a different owner and a different cost path. The electrician and the utility, not a website, decide what is yours to replace. If a quote is silent on the service conductors, ask. A “200-amp panel” line item is not an answer.
After the job, the rating you enter in the calculator should be the service you actually have, including those conductors, not the number on a cabinet that was never fully upgraded.
This is not a permit calculation, a utility approval, or a substitute for a licensed electrician, HVAC contractor, or the authority having jurisdiction. Panel Headroom is an independent educational site. It is not a utility, a certification body, or a contractor. Electrical and generator work that is done incorrectly can cause fire, shock, or carbon monoxide poisoning. Use the adopted electrical code and manufacturer instructions; pull permits where required.