There are two ways:

1. Amp-Clamp, it is a probe that clamps around the wire and measures the current. You must already have a meter that measures current, usually they don't come with the meter unless its a serious meter like a Fluke, but can be bought seperatley.

2. You can hook up your meter in series with the hot lead, assuming it measures DC current.

Just get a car battery, hook the ground wire to the ground post of the battery, the + wire to one lead of the meter, and the other lead to the battery.

 

I just have one of those generic digital multi-meters. Which sttign do I wanna put it on? Thanks!

 

Before you try that make sure your meter is fused for thay high of amperage. Most DVM are fused around 20amps.

I used a amp meter clamp and my SN95 pulls about 50amps on start up and about 36-38 continous.

 

You would have to put it on DC current or it might be listed as DC 'i'.

 

Try to fins an old series amp meter that was standard on cars many years ago - I have one in my tool box just for such reasons. A clamp on meter must be a hall effect clamp since it's DC current. They are kinda expensive.