Polarity Test

The purpose of the polarity test is to verify that receptacles in patient care areas are connected with the proper polarity and that bonding is correct. Particular care shall be taken to ensure correct polarity based on the critical and varied use of receptacles in patient care areas. This test will help verify that Clause 5.6.2 of CSA Z32, has been met in all health care facilities (including hospitals and clinics). The explanation that follows is provided as a general guide and should only be performed by qualified personnel using the appropriate test equipment. Please consult the current applicable electrical safety codes in effect for your area.

Before voltage measurements are made, the breaker feeding the receptacle under test must be closed and a known, reference ground point must be available.

Polarity Test Configuration
Polarity Test Configuration

Test Procedure

  1. With the breaker open, perform a visual check to ensure that the neutral conductor is connected to the silver screw (orange conductor in isolated circuits) and the “live” conductor is connected to the brass screw on the receptacle.
  2. Ensure that the bonding conductor is connected to the outlet box bonding screw and the receptacle bonding screw.
  3. Verify that all bonding conductors are brought to either a separate bonding busbar, or the bonding busbar in the panelboard.
  4. Verify that a known ground reference is available, close the breaker and measure and record the voltages between all receptacle contact points.

Test Results

When the entire test is complete, you will end up with four measurements:

  • The line-neutral voltage, VLN
  • The line-ground voltage, VLG
  • The neutral-ground voltage, VNG
  • The ground-reference (ground) voltage VGR

Example

Suppose a CSA 5-15R receptacle has been wired correctly (verified visually) and the following measurements have been made with the breaker closed:

VLN = 121.6 V
VLG = 121.8 V
VNG = 0.19 V
VGR = 0.01 V

These results show that the receptacle polarity is correct and has met Clause 5.6.2 of CSA Z32.

What to watch out for…

  • Be wary of the small hand-held receptacle testers with three indicators. These devices cannot perform a ground to reference‑ground measurement. A dangerous wiring error known as “reverse bootleg ground” shows up as correctly wired by these devices.
  • Some (more expensive) hand-held testers infer a ground/neutral reversal through voltage measurement and cannot be guaranteed

How often should this test be performed?

This test is performed upon completion of new construction or major renovation or additions to existing installations or when receptacles are replaced.

What test equipment do I need?

The ALTS2400 CSA Z32 Test System will perform polarity test measurements quickly and easily for grounded 120 V circuits (15 A and 20 A).