Proper Way To Use An Oscope On Grounded Battery Bank

[frostheave]

Hi All, I am very much a noob when it comes to using an oscope and am looking to learn.  A recent post about measuring high current DC got me wondering about the following hypothetical question.

Say we have a small -48Vdc battery plant and want to measure the voltage of the plant with a scope.  The battery charger, scope, and battery plant are all connected to Earth Ground, as seen in the picture below.  What is the Proper and Safe way to perform the measurement?

Thank-you for your help.

[tautech]

Your diagram looks correct.
When in doubt check with a DMM for voltage from where you wish to clip the reference lead (Gnd) to Scope BNC's (mains Gnd)
If they are connected(common) there is often no need to attach the reference lead for simple measurements.

[frostheave]

Good deal.  Thanks tautech.