Panel Load Balance Calculator

About the Panel Load Balance Calculator

Helps balance a load center by totalling the watts on each of the two 120 V legs (A and B) and reporting the imbalance.

How to use this calculator

1. Enter the load on each panel leg, usually in watts, amps, or volt-amperes, depending on the calculator setup.
2. Check the total load on each leg and the difference between them.
3. Review the balance percentage or imbalance amount shown by the calculator.
4. Move circuits between legs if needed, then recalculate to see the improvement.

The formula explained

The basic idea is to compare the two leg totals and measure how far apart they are. A common way to express this is using \(\text{difference} = |L_1 - L_2|\), where \(L_1\) and \(L_2\) are the loads on the two legs.

• \(L_1\) = load on the first panel leg
• \(L_2\) = load on the second panel leg
• \(\text{difference}\) = the absolute difference between the two leg loads

Step by step method

1. Add up the loads connected to each leg separately.
2. Find the difference by subtracting the smaller total from the larger total, then take the absolute value.
3. Compare the two totals to see whether one leg is carrying noticeably more load.
4. If the loads are uneven, move one or more circuits and check the totals again.

Worked example

Problem. A panel has \(2{,}400\) watts on leg \(1\) and \(1{,}800\) watts on leg \(2\). Find the load difference.

1. Write the two leg loads as \(L_1 = 2{,}400\) and \(L_2 = 1{,}800\).
2. Compute the difference: \(\text{difference} = |2{,}400 - 1{,}800| = |600|\).
3. So the load difference is \(600\) watts.

Tips and common mistakes

• Use the same unit for both legs, because mixing watts and amps gives a misleading result.
• A small difference is usually fine, but a large difference may mean you should shift a circuit to the lighter leg.

Frequently asked questions