EPZ 100/350 Ex Isolating Spark Gap for Zone 2 Hazardous Areas
A spark gap designed for Zone 2. Electrical isolation during normal operation. Equipotential bonding during lightning surges.
When Direct Bonding Isn’t an Option
Some electrical installations need to remain electrically isolated during normal operation.
Consider an oil-and-gas pipeline with insulating flanges. Connecting the separated sections permanently can defeat the purpose of the insulation. But during a lightning strike or nearby electrical fault, a dangerous voltage difference can develop across those same sections.
The same problem can occur when two grounding systems must remain separate for functional reasons.
An isolating spark gap (ISG) addresses this conflict.
It keeps conductive systems electrically separated under normal conditions, then provides a temporary conductive path when a surge drives the voltage high enough to cause sparkover.
The Solution: Raycap EPZ 100/350 Ex
The Raycap EPZ 100/350 Ex is an isolating spark gap designed for applications requiring electrical isolation and lightning-surge equipotential bonding in Zone 2 hazardous gas atmospheres.
It provides rated withstand voltages of 240 V AC and 350 V DC. During a sufficiently high transient overvoltage, its internal spark gap conducts, connecting the otherwise isolated systems.
The device is rated to carry a 25 kA lightning impulse current (10/350 µs), corresponding to Class 1L under IEC 62561-3.
After the transient has ended and the spark gap extinguishes, the device returns to its isolating state.
Why Is a Spark Gap Permitted in Zone 2?
A conventional exposed spark can ignite a flammable gas atmosphere.
The EPZ 100/350 Ex uses a hermetically sealed construction and carries the hazardous-area marking Ex nC IIC T5 Gc.
Its sparkover occurs within the device’s certified protection arrangement rather than across an exposed connection.
The Ex nC marking identifies a protection concept used for equipment with components capable of producing operational sparks, under the applicable requirements of IEC 60079-15.
Here’s what its classification tells you:
- Ex nC: Type-of-protection marking for a protected sparking component.
- IIC: The gas group encompassing demanding atmospheres, including hydrogen and acetylene.
- T5: Temperature class limiting maximum equipment surface temperature to 100°C under the applicable rated conditions.
- Gc: Equipment Protection Level suitable for Zone 2 gas applications.
The certified hazardous-area ambient range is −30°C to +70°C.
The manufacturer’s mechanical temperature specification extends to −40°C, but the Ex certification marking establishes the narrower lower limit for hazardous-area use.
Where EPZ 100/350 Ex Is Used
Pipeline Insulating Flanges
Oil-and-gas pipelines can contain insulated sections that must remain electrically separated.
An isolating spark gap can provide a temporary conductive path during a surge, reducing the risk of uncontrolled flashover across insulating components.
Separate Grounding Systems
Some installations use separate grounding arrangements for functional reasons, such as signal-ground and power-ground systems.
The EPZ can provide surge-triggered equipotential bonding without permanently joining those systems during normal operation.
Lightning Protection Bonding
Where a direct metallic bond is not permissible, an isolating spark gap can provide indirect bonding between a lightning protection system and nearby conductive metalwork.
The final connection arrangement must follow the applicable lightning protection and hazardous-area installation requirements.
Electrical and Mechanical Specifications
| Specification | Value |
|---|---|
| Manufacturer | Raycap |
| Model | EPZ 100/350 Ex |
| ISG Classification | Class 1L |
| AC Withstand Voltage | 240 V |
| DC Withstand Voltage | 350 V |
| Rated Impulse Sparkover Voltage | 1,000 V |
| Impulse Discharge Current, 10/350 µs | 25 kA |
| Maximum Discharge Current, 8/20 µs | 100 kA |
| Specific Energy | 156 kJ/Ω |
| Charge | 12.5 As |
| Residual Voltage at 5 kA, 8/20 µs | 1.6 kV |
| Capacitance at 1 MHz | Less than 10 pF |
| Enclosure Protection | IP67 |
| Housing | Metal tube |
| Body Dimensions | Ø28 × 140 mm |
| Overall Length Including Leads | Approximately 950 mm |
| Conductor Cross-Section | 16 mm² |
| Weight | Approximately 500 g |
| Installation | Indoor / Outdoor |
What does Class 1L mean?
Class 1L is a standardized light-duty ISG classification under IEC 62561-3, associated with a 25 kA (10/350 µs) impulse current.
The product’s 100 kA rating applies to the shorter 8/20 µs waveform. It does not mean the device is rated for 100 kA at 10/350 µs.
View EPZ 100/350 Ex Technical Datasheet
Certification and Installation Considerations
The EPZ 100/350 Ex datasheet identifies the following certificate references:
| Certification | Reference |
|---|---|
| IECEx | IECEx BAS 15.0069X |
| ATEX | Basefa15ATEX0102X |
| IECEx Marking | Ex nC IIC T5 Gc |
| ATEX Marking | II 3G Ex nC IIC T5 Gc |
The datasheet references IEC 60079-0, IEC 60079-15, and EN 62561-3.
For installation design, IEC 60079-14 and IEC 62305-3 are also relevant standards to consider. They are not additional product certifications claimed by this datasheet.
Important: External Sleeve Precaution
The EPZ has an external non-metallic heat-shrink sleeve that can present an electrostatic charging hazard.
Installers must follow the manufacturer’s specific installation instructions and certificate conditions. Nearby hot surfaces, including pipelines, must also be considered to ensure the certified ambient temperature limit is not exceeded.
Why Bonding Design Still Matters
An isolating spark gap is selected because a direct permanent bond may not be appropriate.
That makes its location and connection arrangement critical.
For a broader discussion of grounding faults and unexpected voltage on grounding conductors, read our article, Why Can Grounding Cables Become Energized? (In Indonesian).
You can also read our LinkedIn explanation of IEC 62305 and coordinated lightning protection.
Related product: M-EARTH Grounding Resistance Reducer for separately engineered grounding-electrode installations.
Need to Bond Two Systems Without Permanently Connecting Them?
Send PT ABO Madalex Indonesia your hazardous-area classification, bonding layout, and electrical isolation requirements.
We’ll review whether EPZ 100/350 Ex is suitable for the proposed connection and identify the technical information needed before installation.
Send Us Your Bonding Requirements
Download EPZ 100/350 Ex Datasheet