Currently working my way through the educational ranks of InterNACHi and I have a few questions on what’s written below directly out of the electrical inspection course. I sure would appreciate if a veteran home inspector could take a moment to help me better understand what’s going on here. I have a feeling I’ve been doing something wrong. Thank you for your time.
Calculating available amperage
In many cases the listing information about a home is incorrect about the service amperage, due to the broker or owner relying solely on the size of the main breaker or fuse. Many people are also mistakenly under the impression that the available amperage is the total of the individual breakers or fuses in the service panel.
The correct way to determine the available amperage is to determine the ampacity of the lowest rated of the following components:
- Service supply
- Electric meter & socket
- Service entrance conductors
- Service disconnect
Here are a couple of examples:
- A 200 amp service lateral, a 200 amp meter and base, a 175 amp rated SEC, a 150 amp rated panel, and a 125 amp service disconnect. = A 125 amp reportable service supply.
*]A 150 amp service drop, a 60 amp meter and base, a 150 amp SEC, a 100 amp rated panel, and a 100 amp service disconnect. = A 60 amp reportable service supply.
A home inspector getting this wrong could potentially end up paying for a service upgrade costing several thousand $$$$$.