Determining Existing Loads
In order to add to existing electrical systems, the Electrical Code requires a load study to determine "actual maximum demand" over a 1-year period or by exception 30-days. ACR Data Loggers are an ideal tool for providing either short or long term load studies.
Having the quickest turnaround, the 30-day load study is the easiest way to determine peak currrent flow to speed up projects. The month long recording method relies on knowing that all contributing loads have been considered by collecting name plate ratings and totalizing the loads – seasonal demand is then calculated. As the electrical code states, the preferred method is to record data for 1 year so all periodic patterns are considered including heating and cooling giving conclusive results – this also eliminates the need to do research on equipment inventory. Either way, installing a single channel AC Current Data Logger attached to the highest loaded phase is all that is required. A 10-year self-powered data logger is ideal as it will fit inside any electrical panel. It measures Amperage 24/7 - 365 days a year providing a graph showing peak demand amperage.
Application Document
Determining Existing Loads (PDF)
Recommended Products
- OWL 300
Single-channel AC Current Data Logger


