heater is operating, shows approximately 4 A of current, this indicates the heater is working properly, because: I⫽
p 1000 ⫽ 4.16 A or E 240
But an ampere reading much different from 4 A (either higher or lower) indicates some fault in either the heater or the branch circuit supplying it.
Recording Ammeters A clamp-on ammeter shows instantaneous current, at a moment in time. But often when troubleshooting electrical equipment and systems, it is more useful to have a record of current over a period of time. Figure 1-2 shows a recording ammeter used for this
1-2 Recording ammeter. 5
