Electrical Measurement Safety

Start by determining any examples of electrical hazards in the working area. This is normally done via a risk assessment. Inspect electrical equipment and systems for signs of damage or incorrect/inappropriate installation. Identify any exposed wiring, poor grounding, or overloaded circuits. It may be necessary to repair or replace electrical equipment if observable faults are found. 

The UK Health and Safety Executive (HSE) lays out the format of a formal risk assessment of the working area that accounts for any electrical hazards. The risk assessment should include details of who may be harmed, the level of risk and how it has been determined, and the precautions taken. The risk assessment should include the type of electrical equipment used, how it is used, and the environment.

Electrical hazards can be mitigated by workers donning the correct electrical PPE as defined by PPE regulations. For example, flame-resistant clothing can prevent harm caused by arc flashes. Insulated boots and gloves may prevent personnel from becoming a conduit for current, guarding against electric shock.

Your electrical PPE inspection checklist should include:

• Electrically insulated hard hats: An insulated hard hat can prevent current from flowing through the head to the rest of the body as well as fulfilling the traditional role of protecting against bumps and falling objects
• Safety glasses: During electrical work, if sparks, molten metal, or other debris flies, the appropriate eyewear protects personnel
• Face shields: Face shields are invaluable for protecting the face from exposure to arcing energy in an arc flash incident. Face shields may come as an entire headpiece or an attachment such as a visor for a hard hat
• Insulating gloves: Insulated gloves protect against shocks and burns and come in different voltage ratings. Use gloves that are appropriate for the voltage you are working with
• Safety shoes: Safety shoes feature toughened toe caps and provide feet protection against falling objects and slips and trips during electrical work. Dielectric overshoes are also available. These provide extra protection against electrical hazards.
• Flame-resistant clothing: Workers can be kitted out in coveralls, trousers, shirts, and jackets that are flame-resistant, guarding against burns from an electrical fire or arc flash. Arc flash suits are complete flame-resistant suits including face shields that are comfortable to wear for extended periods. Use arc flash-rated PPE when working with high voltages

It’s also important to use the correct electrical test tools for jobs such as electrical current measurement. Test and measurement tools measure a range of values including current, voltage, resistance, and power. The principal tools engineers use to make measurements include ammeters (which measure current), ohmmeters (which measure resistance), and voltmeters (which measure the potential difference between two points of a closed electrical circuit). Other measurement tools include multimeters, which are capable of measuring multiple different parameters including voltage, resistance, and capacitance, and thermal imaging cameras to detect hot spots in cabinets.

Before performing electrical testing, engineers should ensure that the environment is appropriately lit so that any hazards are clearly visible. This can be via existing installed area lighting, temporary site lighting, or even head torches in confined spaces. For example, it should be readily possible to distinguish different colours of wiring insulation. There should also be adequate emergency lighting in the event of unexpected power loss.

It poses an additional risk if you work alone in an industrial environment when carrying out electrical work. If there is an incident, it is good to have someone there who can come to your aid, which is not the case if you are working in isolation. Many domestic electricians, of course, work alone. But in particularly hazardous industrial environments, having a fellow electrical maintenance engineer on hand is good practice when it comes to electrical safety. 

It may not always be possible when measuring electrical properties, but the best means of guarding against injury from electricity is to remove the source of power from the equation altogether by de-energising the equipment. This eliminates the possibility of shock. Machinery should also be marked as de-energised using the correct lockout / tagout procedure, which will prevent it from being accidentally re-energised. The circuit should also be tested for voltage after lockout with a known, good tester prior to any work commencing to ensure the circuit is really dead.