I've used a 60-0-60 ammeter with leads on it for yrs. Also have the two models of Snap-On ammeters you just lay over the wire, if I recall one is up to 300A. & the other is a 60A. Another tool I use a lot is a jumper with a screw terminal circuit breaker in it. That way I can change the breaker depending what I'm trouble shooting & connect it & go to where the component is to see what it does as the breaker cycles on & off. Doug