I bought the following ampere meter http://www.ebay.com/itm/151314913968?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649.
I thought I would get a meter and a external shunt resistor but I only got the meter. So I think it has a internal shunt resistor (I have seen that meters with external shunt often have a "resistor symbol" and a mV rating).
Is it common to have a internal shunt resistor for a 30A meter? I don't want it to burn up or something :)