What do Ex db IIB T6 Gb and Ex db IIC T6 Gb Mean?

MAXON confirms that all of its explosion-proof wireless devices hold GB/T 3836 certification. All Models carry Ex db IIB T6 Gb&Ex tb IIIC T80°C Db or Ex db IIC T6 Gb&Ex tb IIIC T80°C Db. The gas group is the difference between the two families; both also carry the stated conductive-dust marking.

The marking must still be read together with the certificate, nameplate, ambient range, installation instructions and the site's hazardous-area classification.

Which MAXON product families carry gas and dust explosion-protection certification?

All MAXON explosion-proof access points, wireless bridges, industrial cellular routers and DTUs hold dual gas-and-dust explosion-protection certification under GB/T 3836. Depending on the certified product configuration, the gas marking is either Ex db IIB T6 Gb or Ex db IIC T6 Gb, while the dust marking is Ex tb IIIC T80°C Db. The exact certificate and product designation should accompany the quotation and final product page.

How do you read Ex db IIC T6 Gb?

This short line is useful only when it is tied to the exact product label and certificate. A category-page description or model-family summary cannot replace those documents.

What does “db” tell the engineer?

Protection type d uses a flameproof enclosure. For MAXON's Chinese certification, GB/T 3836.2-2021 covers equipment protected by flameproof enclosures d. The enclosure is designed to withstand an internal explosion and prevent flame transmission to the explosive atmosphere around it under the conditions of the certified construction.

The suffix in db links that protection concept to Equipment Protection Level Gb. The marking does not mean the equipment cannot contain an ignition-capable component. It means the complete certified construction controls that hazard through the specified protection method.

This distinction matters for wireless equipment. A radio board, power converter or Ethernet device placed inside a generic metal box does not automatically become Ex db. Flame paths, cover fasteners, cable entries, unused openings, internal layout and thermal behaviour belong to the assessed design.

What does gas group IIC mean?

The equipment groups should be distinguished correctly: Group I concerns mines susceptible to firedamp, Group II concerns explosive gas atmospheres other than those mines, and Group III concerns explosive dust atmospheres. IIA, IIB and IIC are subdivisions within Group II.

IIB and IIC identify the gas subgroup covered by the equipment marking. The required group must match the actual gas or vapour identified in the hazardous-area classification.

What does temperature class T6 mean?

The temperature class limits the equipment's maximum surface temperature under the conditions assessed for the marking. T6 means a maximum surface temperature of 85°C. It is a gas-atmosphere temperature class, not the normal operating temperature of the radio and not an ambient-temperature specification.

Three temperatures are easy to confuse:

· the ambient range in which the equipment is approved to operate;

· the internal component or enclosure temperature during service;

· the maximum surface-temperature class shown in the Ex marking.

A buyer should therefore request the complete marking, approved ambient range and certificate conditions. A T6 label copied from another product cannot qualify a different enclosure, radio, power input or antenna arrangement.

What does Equipment Protection Level Gb mean?

Gb is an Equipment Protection Level for explosive gas atmospheres. It is used for Zone 1 and Zone 2 applications, subject to the site's classification, the GB/T 3836 certificate and the installation requirements. It addresses ignition risks during normal operation and expected faults within the certified protection concept.

The project engineer still needs to check:

1. the formal zone or division classification;

2. the gas group and temperature requirement;

3. the required EPL or regional equipment category;

4. ambient, mechanical, ingress and corrosion conditions;

5. the exact certification scheme accepted in the destination market.

Does the Ex prefix prove ATEX or IECEx certification?

No. Ex is a standardized explosion-protection marking prefix, not the name of a certification scheme. The marking does not by itself prove that a product holds ATEX, IECEx, UKEX or a North American approval.

MAXON confirms that its explosion-proof equipment holds GB/T 3836 certificates. MAXON has not stated that these products hold IEC 60079-1 certificates, IECEx certificates or ATEX certificates. Overseas buyers must check whether GB/T 3836 certification is accepted for the destination project and should receive the exact MAXON certificate for the supplied model.

How does Ex db IIC T6 Gb differ from Ex tb IIIC T80°C Db?

The first marking addresses gas-atmosphere protection using a flameproof enclosure. The second addresses combustible-dust protection by enclosure and states a maximum surface temperature in degrees Celsius.

One line should not be silently substituted for the other. If a product carries both, verify both complete markings on the same certificate and nameplate.

What should an RFQ request?

For an explosion-proof wireless access point, bridge, router or DTU, include the following in the request:

· installation country and accepted certification scheme;

· zone or division and required EPL;

· gas or vapour group and required temperature class;

· minimum and maximum ambient temperature;

· enclosure material and corrosion exposure;

· cable-gland, conduit and unused-entry requirements;

· power input, grounding and surge-protection design;

· radio standard, bands, antenna arrangement and local spectrum rules;

· current certificate, complete model designation and nameplate drawing.

This information allows safety qualification to happen before throughput, WiFi generation or cellular speed is discussed.

FAQ:

Is Ex db IIC T6 Gb the same as IP68?

No. IP68 is an ingress-protection rating for dust and water conditions defined by the applicable IP standard. It does not demonstrate control of ignition hazards in an explosive atmosphere. A product may need both an appropriate Ex marking and an ingress rating.

Can Ex db IIC T6 Gb equipment be used in Zone 0?

Do not assume so. Gb is not the highest gas Equipment Protection Level. The site's classification, required EPL, local regulations and certificate scope determine suitability.

Can a standard WiFi access point be installed inside an Ex enclosure?

Only as part of an engineered and appropriately assessed configuration. The enclosure, heat load, cable entries, antennas, power system and internal equipment all affect compliance.

Is the marking enough to approve a purchase?

No. Request the current certificate, product schedule or annex, nameplate, instructions and any special conditions of use. Check that the ordered hardware matches them.

Ask MAXON for a document-based configuration review

Send the site classification, gas group, temperature requirement, ambient range, destination market, wireless function and preferred power interface. MAXON can then identify a candidate product and provide the available compliance documents for customer verification.

Related technical guides

• Explosion-Proof Wireless Communication: A Practical Guide for Hazardous Areas
• What Does Ex tb IIIC T80°C Db Mean?
• How to Select an Explosion-Proof Wireless Access Point
• Hazardous-Area Wireless Network Architecture