What is non-conductive (dielectric)?
Non-conductive, or dielectric, describes a material or substance that acts as an electrical insulator, meaning it does not let electric current pass through it.
The term should not be read too broadly, though. Whether something is non-conductive depends on the test conditions, the type of substance, the concentration, the discharge distance, the voltage, and the conditions around it.
How does being non-conductive relate to fire extinguishers?
Being non-conductive, or holding a dielectric property, matters to fire extinguishers in three ways: whether the extinguisher can be used on a Class C fire, the safety of the person using it, and the protection of the electronic equipment.
It decides whether an extinguisher can be used on a Class C fire. Under international standards such as NFPA and EN 3, fires are sorted into classes, and Class C covers fires involving energized electrical equipment. An agent that conducts electricity, plain water or firefighting foam for instance, must never be used on a Class C fire.
It stops current tracking back to the person using the extinguisher. When someone discharges an extinguisher at a fire involving high voltage wiring or electrical equipment, the stream of gas or mist leaves the nozzle and makes direct contact with the live current.
If the agent conducts electricity, the current can travel back along that stream, into the cylinder, and electrocute the user.
If the agent is dielectric, the stream acts as an insulator instead, so the current cannot travel back and reach the person holding the extinguisher.
For PAF GLOBAL products, read more at What is PAF-222, What is FK5112 / What is FK-5-1-12, and What is Perfluorohexanone
Which areas should pay attention to dielectric properties?
Data centers and server rooms
Telecommunication exchange rooms, covering telephone exchange and network equipment
Control and monitoring rooms, covering IT control rooms and central display walls
Main distribution board (MDB) rooms, holding a building's main switchgear and electrical controls
Transformer rooms, for transformers installed indoors
UPS and battery rooms, holding backup power and lithium or lead-acid batteries
Solar inverter rooms
EV charging stations and battery storage areas
Marine engine and switchboard rooms, on ships or yachts
Aviation radar rooms and flight simulators
Comparing extinguisher types for electrical equipment
Clean agent extinguishers
Clean agent extinguishers are a popular choice around electrical equipment, because they leave no residue after a discharge. That suits areas holding servers, UPS units, MDB cabinets, control panels, or other critical electronics.
CO2 extinguishers
CO2 extinguishers leave no chemical powder residue, so they are commonly used for certain electrical applications. Take care over use in enclosed spaces, ventilation and operator safety, though. For the detailed comparison, read Clean Agent and CO2
Dry chemical extinguishers
Dry chemical extinguishers suit a wide variety of general areas. Used in areas holding electronic equipment, though, the chemical residue after a discharge needs particular care. For the direct comparison with clean agents, read Clean Agent and Dry Chemical
Foam and water extinguishers
Foam and water extinguishers suit only certain kinds of risk. As a rule they are not the main choice for electrical or electronic equipment, because they leave liquid and moisture behind, which can cause damage.
What to know before choosing an extinguisher for electrical equipment
Choosing an extinguisher for electrical equipment, meaning Class C fires, takes care. It has to put the fire out quickly, keep the operator from being shocked, and avoid adding to the damage to the electronics through chemical residue.
It has to be non-conductive: dielectric, or Class C approved.
Choose by what you need and how it will be used, such as whether a portable cylinder is enough or an automatic system should go in alongside it.
Decide whether residue after a discharge has to be kept down.
You can contact PAF GLOBAL here: Contact for Consultation
What to read next
Now that you know non-conductive means insulating under a set of stated conditions, these related topics on clean agents and areas holding electrical equipment follow on:
Clean Agent Fire Extinguishers
How clean agent cylinders are used with electrical and critical equipment.What is FK5112 / What is FK-5-1-12
The clean agent most often discussed alongside non-conductive and residue-free properties.What is Perfluorohexanone
The chemical name of the substance behind FK5112 and FK-5-1-12.What is PAF-222
The detail on the PAF-222 solution, PAF GLOBAL's primary product.Fire Extinguishers for Data Centers / Server Rooms / Electrical Rooms
For anyone selecting extinguishers for areas holding critical electrical and IT systems.Fire Suppression Systems for MDB Cabinets and Control Panels
For choosing how to protect electrical cabinets, MDBs and control panels with localized systems.Residue-Free Clean Agent Fire Extinguishers
Why leaving no residue matters so much near electrical and electronic equipment.Contact for Consultation
To ask PAF GLOBAL for more information.
Frequently Asked Questions (FAQ)
1. What is non-conductive (dielectric)?
It is the property of an electrical insulator: current cannot pass through it. It holds up under high voltage without causing a shock, a short circuit, or current travelling back to harm the user.
2. Does a non-conductive agent mean it can be used on electrical equipment in every case?
No. There are cases where it does not fit. In an open or outdoor area, a gaseous agent gets blown about by the wind and diluted, so it cannot put the fire out.
3. What is dielectric strength?
The higher an agent's dielectric strength, the better it resists electrical shock and the higher the voltage it can withstand.
4. What should you look at when choosing an extinguisher for a room holding electrical equipment?
The Class C or non-conductive marking, which confirms the agent acts as an electrical insulator, so current does not travel back and shock the user on discharge.
And whether it leaves residue. Choose a clean agent, PAF-222 Clean Agent FK-5-1-12 for instance.