IBM 3931 User Manual

Procedure B
This procedure checks for a ground/earth resistance of 1 ohm or less at the receptacle ground/earth pin
using the digital voltage meter.
The wall breaker should be OFF.
Ground/Earth
4 pins
L1
L2
L3
Ground/Earth
5 pins
Neutral
L2 L3
L1
__ 1. Using the digital voltage meter, measure the resistance from the ground/earth pin of the receptacle
to building ground/earth. The reading should be 1 ohm or less.
__ 2. For metal receptacle shells or shells with metal components, also measure the resistance from the
ground/earth pin of the receptacle to the metal. This reading should be 0.1 ohm or less.
Note: Digital meters might give unstable resistance readings if leakage current is flowing in the
building ground/earth circuit. If the reading is above (or is fluctuating above) 1 ohm, STOP.
a. Have the customer's electrician inspect the ground path back to the power source.
b. If the electrician corrects the problem, retest.
c. If the problem persists and the electrician has conrmed that the ground from the receptacle
back to the power source is acceptable:
__ i) Document the electrician’s nding in the installation report
__ ii) Notify the supporting IPR for the account
ENG-8 IBM: 3931 Safety Inspection

IBM 3931 Specifications

General

Brand	IBM
Model	3931
Category	Network Hardware
Language	English