Mobile Site        Sitemap        Copyright © 2016 Electrical101.com. All Rights Reserved.        Terms of Use

Sitemap

Switches | Outlets & Plugs | Ballasts | Replace Ballasts | Troubleshooting | Light Bulbs | Basic Electricity | Save Energy | Misc Articles

Electrical101
Multi-wire Branch Circuit Wiring Diagram Open Neutral Wiring Diagram

Open Neutral

Open Neutral Wiring

In an electrical system, ground and neutral are connected together in one location only, at the neutral point. This connection is either at the power company transformer or in the main electrical panel of the dwelling (see Electrical Circuits).

The voltage on a neutral wire is normally 0 volts (V) on a live circuit. However, if a neutral wire is open, the voltage on the line side of this open neutral is 120 V.

Sometimes electricians forget about this while working on a live circuit and get a shock from an open neutral wire.

Multi-wire Branch Circuit Wiring Diagrams

Open Neutral Wiring Diagram

In the diagram above right, the neutral is opened. The neutral wire on the left side of the open (comes from the panel) is 0 V. The wire on the right side of the open (goes to the load) is 120 V.

“A” phase circuit breaker is turned off

In the diagram above right, the A phase circuit breaker is turned off. The neutral wire on the left side of the open (comes from the panel) is 0 V. The wire on the right side of the open (goes to the load) is 120 V.

Even though the A phase circuit breaker is turned off, there is still 120 V on the load side of the open because the B phase circuit breaker is turned on.

If both circuit breakers are closed in the right side diagram, there would be 240 V present at the open neutral instead of 120 V.

See Multi-wire Branch Circuits for more information.

Open Neutral Wiring Diagram

A and B phase circuit breakers are turned off

In the diagram above right, the A phase and B phase circuit breakers are turned off. The neutral wire on the left side of the open (goes to the panel) is 0 V. The wire on the right side of the open (goes to the load) is also 0 V.

Since the A and B phase circuit breakers are turned off, there is now 0 V on the load side of the open.

See Multi-wire Branch Circuits and Open Neutral Multi-wire Circuit for more information.

Home

Electrical Troubleshoot ing

Electrical Meters and Testers

Battery Testers

Input Impedance

High Wattage Appliances

Circuit Breakers

Test and Troubleshoot Outlets

Test and Troubleshoot GFCIs

Troubleshoot Lights

Troubleshoot Switches

Troubleshoot 3-way Switches

Troubleshoot 4-way Switches

Open Neutral

Open Neutral Multi-wire Circuit

No Power to Outlets

Troubleshoot Garage Door Opener