How to Determine Load Center Size in Sub Panels

If you are planning on adding new appliances, or rewiring anything in your home, knowing how to find the load size in the sub panels is important. If you overtax the panel, you risk blowing fuses and causing bigger problems with the electrical wiring in the home. Here are some things to check to determine the load center size in sub panels.

Check the Main Breaker

Sometimes the main breaker box will have information in the box regarding the sub panels. This isn't always the case, but it will save you a lot of time by checking here first.

Calculations

This is more complicated, but it will give you the most accurate determination for the load size. To do this you will need to know what the main breaker can handle, and how much is of this is isolated in each sub panel. Most newer homes and apartments will have sub panels of 200 amp. Older homes may only have 100 amp branch panels. Try to check with the manufacturer of the sub panel itself to find what it can handle. The appliances you plan on having on the sub panel will also determine the size that is needed. For a few lights, a smaller load is okay. For larger appliances, you will want to go with 100 or 200 amps.