Amps on external power supply

If the external drive power supply is 2 amps, is the drive drawing 2 amps even when idle?

no, it will fluctuate when the drive is idle and under load when being accessed (but not exceeding 2 amps)

i have a USB Voltage/Amp tester and can observe this.

Thanks! I have several external drives (each with their own AC power adapters), some are even rated at 3 AMPs, if I add the AMPS they exceed 15 AMPS–more than the rating of the AC line to which they are attached to.

It is rare that any two are accessing data simultaneously–the others are just “loafing”.

I would still advise not to exceed the total amps the power line can supply … to be on the safe side.

Plug some of the drives into a different AC socket. (a house typically has 100 AMPS distributed to all the sockets in the house)

I have several hard drives plugged into a power board rated at 10 AMPS … but i still, never have more the 3 drives powered on at the same time.