“Explosion-proof” is not a complete motor specification. Before comparing suppliers, obtain the site’s classification requirements and have the proposed motor reviewed against them. Do not choose a classification from a product advertisement.
Buyers often begin with power, voltage and price. Those details matter, but a motor can match the mechanical duty while remaining unsuitable for the intended location. A useful procurement brief connects the installation requirements, the motor’s documented marking and its operating conditions.
Who should define the classification?
The site’s competent technical team should provide the required classification and acceptance criteria. A sourcing coordinator can obtain files, compare supplier responses and flag missing information. That role should not silently become responsibility for classifying the installation.
For US workplaces, OSHA’s hazardous-location requirements distinguish hazards by the substances present and the likelihood of a hazardous concentration. The rule also addresses equipment selection for classified locations. This is why a general phrase such as “chemical factory motor” cannot replace the site specification.
Keep classification systems distinct
| Information | Procurement question |
|---|---|
| Applicable system and jurisdiction | Which scheme and local acceptance requirements apply to this installation? |
| Classified area requirements | What exact classification has the site’s responsible team specified? |
| Gas, vapour or dust conditions | What material-related group information must the supplier address? |
| Temperature requirements | What temperature limits and operating conditions must be satisfied? |
| Equipment marking and protection concept | What documented marking is proposed, and who will approve it? |
| Installation conditions | Which restrictions must the installer and end user follow? |
Class/Division and Zone terminology should not be converted through a casual one-line equivalence table. Keep the original requirement in the enquiry and ask the supplier to explain the proposed match. If the project uses more than one system, let the designated reviewer resolve the relationship.
Similarly, hazardous-location motor, flameproof motor and explosion-proof motor may appear in overlapping searches, but search wording does not establish technical equivalence. The order needs the actual requirement and proposed protection details.
Separate explosion protection from ordinary motor ratings
An IP rating, insulation designation, efficiency claim or outdoor-use description answers a different question from hazardous-location suitability. Collect each required rating in its own field. Do not let an impressive general specification conceal a missing protection requirement.
The European Commission’s ATEX guidance page separates the equipment framework from workplace responsibilities. For procurement, the practical lesson is to identify both the equipment documentation and the installation requirements rather than assuming one supplier certificate completes the whole project.
Operating conditions belong in the same enquiry
| Detail | What to send to the supplier |
|---|---|
| Electrical supply | Voltage, frequency, phase and allowed variations specified by the project. |
| Load and duty | Required output, speed, duty and the driven equipment description. |
| Environment | Ambient range, altitude, indoor/outdoor location and relevant exposure conditions. |
| Drive arrangement | Whether inverter operation is required, with the proposed speed range and controls. |
| Mechanical interface | Mounting, shaft and flange dimensions, drawing and available space. |
| Accessories | Required heaters, sensors, brakes or terminal arrangements, with explicit scope. |
These are information requests, not a universal technical acceptance table. Ask the supplier to state restrictions and deviations. A change in speed control, accessory or environment should trigger review rather than being treated as a harmless purchasing substitution.
Use a written deviation list
Require each quotation to say “complies,” “deviation” or “not confirmed” against the enquiry fields. Silence is not agreement. This makes a partially documented offer easier to distinguish from an offer that has actually answered the specification.
Before a deposit, close the items that determine technical acceptance. Put approved details into a dated specification attachment. If production proposes a replacement, send the change back to the designated reviewer rather than accepting it only because the size and power remain the same.
What should the final purchasing record contain?
Retain the site requirement, approved datasheet, relevant documents, drawings, deviation decisions and the accepted model designation. Keep a revision list so the factory, buyer and receiving team refer to the same version.
Then connect that record to the motor certificate review and the inspection scope. Physical checks can record the delivered marking and configuration; they cannot recreate the certification tests or approve an installation.
Frequently asked questions
Can a supplier choose the classification for me?
A supplier can propose equipment against a clear requirement. The site’s responsible technical team should define and approve the installation requirements.
Does a higher IP rating mean better explosion protection?
Do not use IP alone to choose a motor for a classified location. Record the required environmental ratings and hazardous-location requirements separately.
Can I order using only a photograph of the old nameplate?
A nameplate is a useful starting point. Add the installation requirement, operating conditions, dimensions and any changes to the application before approving a replacement.
Should I mention an inverter in the RFQ?
Yes. State the intended drive arrangement and speed range so the supplier and responsible reviewer can evaluate the proposed configuration and any restrictions.
Bryan’s Perspective
The most useful sourcing work sometimes happens before anyone asks for a price. Getting the requirement into a form that every supplier can answer prevents confusion later. When a classification is unclear, the responsible action is to bring the question back to the right technical person and keep it open until it is resolved.
Need help turning the specification into a supplier enquiry?
Global China Bridge helps overseas businesses prepare supplier enquiries, compare responses and coordinate factory communication in China. We can collect the technical records your reviewer needs and support agreed on-site checks, production follow-up and shipment preparation.
Contact service@globalchinabridge.com, or tell us about your project. An initial conversation is free; any paid work starts with an agreed scope.
Related reading
Explosion-proof motor RFQ checklist · Certificate checks before ordering
Updated: October 25, 2026