Electrical Insulation & Non-Conductivity
No Free Electrons — by Chemistry
Glass fibers are inorganic insulators; the thermoset resin is an organic insulator. Neither phase has free electrons, so a properly cured FRP panel does not conduct. Dielectric strength is typically 10-20 kV/mm (indicative), compared with mild steel which is a conductor.
Electrical Data Sheet Values
| Property | Typical Value | Test Method |
|---|---|---|
| Dielectric strength | 10-20 kV/mm | ASTM D149 |
| Volume resistivity | > 10^12 Ohm-cm | ASTM D257 |
| Surface resistivity | > 10^11 Ohm (dry, clean) | ASTM D257 |
| Dielectric constant | 4-5 at 60 Hz | ASTM D150 |
| Dissipation factor | 0.01-0.03 at 60 Hz | ASTM D150 |
| Arc resistance | 120-180 s | ASTM D495 |
Indicative values; confirm against the specific resin grade data sheet for high-voltage service.
Where Non-Conductivity Is Critical
Electrical Substations
Switchyard platforms and transformer access where step-and-touch voltage must be eliminated.
Transformer & Switchgear Rooms
Indoor operating platforms around live switchgear; reduces shock risk during maintenance.
Busbar Access & Battery Rooms
Around DC busbars and battery racks where stray current tracking is a hazard.
Electrolysis & Electroplating
DC process cells; FRP avoids both conduction and chemical attack from electrolytes.
Lightning Protection Zones
Non-conductive decks do not provide an unintended down-conductor path.
Live-Line Working Platforms
Overhead-line maintenance platforms where the worker must not bridge live parts.
What You Do Not Need to Design For
No Grounding / Bonding
Unlike steel grating, FRP introduces no conductive path, so no earthing grid, no bonding jumpers and no cathodic protection is required for the grating itself.
No Step-and-Touch Voltage
A fault current on a steel platform can create dangerous touch potentials across walking surfaces. FRP breaks this path automatically.
No Galvanic Coupling
FRP does not couple galvanically with buried pipes, reinforced concrete rebar or dissimilar metals in contact with it.
No Stray-Current Path
No continuous metal path means stray DC from transit or cathodic systems cannot find its way across the deck.
When You Actually Want Some Conductivity
In explosive or dusty atmospheres, static electricity must not build up and spark. A carbon-loaded or metal-loaded conductive (static-dissipative) FRP is available, with surface resistivity of 10^4-10^6 Ohm — conductive enough to bleed static, but not a conductor like steel. This is a different product from insulating FRP; specify it explicitly.
References to Cite
| Standard | Scope |
|---|---|
| ASTM D149 | Dielectric breakdown voltage of solid electrical insulation |
| ASTM D257 | DC resistance / conductance of insulating materials |
| IEC 60243 | International equivalent for electric strength of solid insulation |
| NEMA LI-1 | Industrial laminations (glass/polyester) material specifications |
| OSHA 1910.302 | Electrical installation safety — general |
| NFPA 70E | Standard for electrical safety in the workplace (arc-flash PPE boundary) |
Keep It Insulating
Fasteners
Use FRP clips or fully coated stainless with insulating washers. A bare metal bolt running through the panel can create a small conductive path if it touches another metal component.
Minimum Thickness
In high-voltage areas, specify a minimum 25 mm panel thickness to provide a dielectric margin over the working voltage.
Moisture
Surface water lowers surface resistivity (not volume resistivity). Keep panels clean and dry; in condensing environments, specify track-resistant resin to prevent surface tracking over decades.
Temperature
Dielectric strength decreases as temperature rises above room temperature, and collapses above the resin Tg. Stay below the resin maximum continuous use temperature.
Proof Tests You Can Specify
| Test | Criterion |
|---|---|
| Dielectric proof test | Apply 2x working voltage for 1 minute; no breakdown or flashover |
| Insulation resistance test | Measure > 100 MOhm between electrodes after 1 minute |
| Material certificate | Resin grade, glass content, dielectric data and batch traceability |
Designing an Insulated Platform?
Tell us working voltage and environment — we return dielectric values and the correct fastener specification.
Source: ZeAllgrate (Fiberglass Grating Manufacturers Council / ACMA) design guidelines; ASTM International; ISO 14122; OSHA 29 CFR 1910. Indicative data for specification guidance only — final design verified by ZeAllgrate engineering against certified load/span charts.