Practical limits

The assumptions are deliberately simple.

FRZ uses basic load maths and plain warning rules so a shop owner, landlord, workshop manager or facilities team can spot obvious problems before kit is plugged in. It does not claim formal compliance with BS 7671, NEC or workplace safety law.

Use real equipment labels

Use input watts or amps from the label. For portable AC, do not use BTU output as the electrical input.

Hidden site conditions

The calculator cannot know whether a circuit is shared, damaged, incorrectly labelled, overloaded elsewhere or unsuitable for the room.