How to Check a Circuit is Dead 

By on

If you want to check a circuit is dead (not live), you should always use the three point method.  First check a known live circuit, then check the dead circuit and finally recheck the live circuit.  Carrying out the procedure ensures that the meter is working before and after testing for the dead circuit.

A few additional measurement tips to make things safe:

  • always connected ground or negative clips first (remove last)
  • hang or rest the test meter (try not to hold in your hand)
  • use PPE - see our PPE Post

 If anyone has other tips to share, please add in the comments below.



Steven McFadyen's avatar Steven McFadyen

Steven has over twenty five years experience working on some of the largest construction projects. He has a deep technical understanding of electrical engineering and is keen to share this knowledge. About the author

myElectrical Engineering

comments powered by Disqus



Variable Frequency Drive

Variable frequency drives are widely used to control the speed of ac motors.  This note looks at the mechanisms which enable drive units to control the...

How to measure power supply quality

If your are ever called out to troubleshoot something on your electrical system, one of the first things consider is the supply voltage. You want to ensure...

Cables for MV Power Distribution - Earthed versus Unearthed Systems

Power cables can basically be classified into earthed and unearthed cables, where earthed and unearthed refer to the application for which the cable is...

Paternoster Lifts

These lifts were first built in 1884 by J. E. Hall and called a paternoster ("Our Father", the first two words of the Lord's Prayer in Latin) due to its...

Motor Insulation

Insulation on a motor prevents interconnection of windings and the winding to earth.  When looking at motors, it is important to understand how the insulation...

What does N+1 mean?

The term 'N+1' relates to redundancy and simply means that if you required 'N' items of equipment for something to work, you would have one additional...

Cable Sheath and Armour Loss

When sizing cables, the heat generated  by losses within any sheath or armour need to be evaluated. When significant, it becomes a factor to be considered...

9 power supply issues solved by using a UPS

Installation of a UPS can help in reducing problems due to issues with the power supply.  A lot of people relate this to nine key issues.  Depending on...

Understanding electric motor insulation & temperature

Anyone specifying or using electric motors should have a basic understanding how the insulation is related to temperature. Three classes of insulation...

Inductance

When current flows within a wire, a magnetic field is created. The potion of this magnetic field perpendicular to the wire is called the magnetic flux...

Have some knowledge to share

If you have some expert knowledge or experience, why not consider sharing this with our community.  

By writing an electrical note, you will be educating our users and at the same time promoting your expertise within the engineering community.

To get started and understand our policy, you can read our How to Write an Electrical Note