Case Study: Verifying Cable Entry Requirements in a Hazardous Area Equipment RFQ
In hazardous-area electrical projects, cable entry requirements can appear straightforward in an RFQ. However, reviewing a vendor quotation requires more than simply counting the number of cable entries.
This case study describes an RFQ review involving multiple cable sizes and demonstrates a practical approach to checking whether a revised vendor quotation properly addresses the original requirement.
1. The RFQ Requirement
The project requirement specified the following cable entries:
| Cable | Required Cable Entries |
|---|---|
| 4 × 50 mm² cable | 3 |
| 10 × 1.5 mm² cable | 3 |
The total requirement was therefore six cable entries, divided into two different cable-size requirements.
This distinction is important. The requirement was not simply for six holes in the enclosure. Each group of cable entries had to accommodate the specified cable size.
2. Reviewing the Vendor's Revised Offer
The vendor subsequently issued a revised quotation. The first step was to determine whether the revised configuration provided the required number of cable entries.
RFQ Requirement
↓
3 cable entries for 4 × 50 mm²
3 cable entries for 10 × 1.5 mm²
However, confirming the total number of entries is only the beginning of the technical review.
3. What Should Be Checked?
3.1 Number of Cable Entries
First, confirm that the vendor's revised offer provides the required total number of entries.
| Requirement | Quantity |
|---|---|
| Entries for 4 × 50 mm² cable | 3 |
| Entries for 10 × 1.5 mm² cable | 3 |
| Total | 6 |
If the vendor offers fewer than six entries, the requirement is clearly not satisfied. If six entries are offered, however, the review should continue.
3.2 Cable Size Allocation
The six entries must be checked against their intended cable sizes.
A quotation stating only "6 cable entries" does not necessarily demonstrate compliance with the RFQ.
The reviewer should establish which entries are intended for the 4 × 50 mm² cables and which are intended for the 10 × 1.5 mm² cables.
3.3 Cable Gland or Cable Entry Size
The next step is to check the proposed cable gland or cable entry size for each cable.
The review should trace the requirement through the following sequence:
Cable size → Cable gland / entry size → Enclosure opening
This prevents a simple quantity check from being mistaken for a complete technical compliance check.
3.4 Enclosure Configuration
The physical arrangement should also be reviewed, including:
- Number of entries
- Entry location
- Available space
- Entry thread
- Cable gland compatibility
- Enclosure configuration
- Applicable Ex certification
This becomes particularly important for certified hazardous-area equipment, where modifications to an enclosure may affect the certified configuration.
4. Why Certification Matters
For hazardous-area equipment, cable entries and cable glands cannot always be treated as independent mechanical components. Their suitability must also be considered in relation to the equipment certification and applicable installation requirements.
The question is therefore not simply:
"Can six holes be provided in the enclosure?"
The more appropriate technical question is:
Is the proposed cable entry arrangement compatible with the offered Ex equipment and its certified configuration?
5. A Common RFQ Review Mistake
A basic quotation review might look like this:
| RFQ | Vendor | Conclusion |
|---|---|---|
| 6 cable entries | 6 cable entries | Compliant |
This check is incomplete.
A more useful technical review should look at each requirement separately:
| Check | RFQ Requirement | Vendor Offer | Status |
|---|---|---|---|
| Total cable entries | 6 | To be verified | Check |
| 4 × 50 mm² entries | 3 | To be verified | Check |
| 10 × 1.5 mm² entries | 3 | To be verified | Check |
| Cable gland / entry size | As required by cable | To be verified | Check |
| Entry thread | Project requirement | To be verified | Check |
| Ex certification compatibility | Required | To be verified | Check |
6. Practical RFQ Review Workflow
For similar hazardous-area equipment inquiries, the following workflow can be used:
RFQ
↓
Identify cable sizes and quantities
↓
Determine required cable entries
↓
Check cable gland / entry size
↓
Check thread and enclosure arrangement
↓
Check Ex certification
↓
Compare with vendor quotation
↓
Identify deviation or clarification
↓
Accept / Clarify / Revise
7. Lesson Learned
The main lesson from this case is simple:
Do not verify an Ex equipment quotation only by counting cable entries. Verify what each entry is intended to accommodate.
For this RFQ, the requirement was not simply:
6 cable entries.
It was:
3 entries for 4 × 50 mm² cables + 3 entries for 10 × 1.5 mm² cables.
Keeping this requirement traceable through the vendor quotation helps identify discrepancies before the quotation becomes a purchase order or reaches the installation stage.
RFQ Review Checklist
- ☐ Total number of cable entries
- ☐ Quantity for each cable size
- ☐ Cable gland / entry size
- ☐ Entry thread
- ☐ Entry location
- ☐ Enclosure configuration
- ☐ Ex certification
- ☐ Compatibility of the proposed cable entries with the certified equipment
- ☐ Any deviation from the original RFQ
- ☐ Vendor clarification where the quotation is unclear
Conclusion
A revised vendor quotation should not be considered technically compliant simply because the number of cable entries appears to match the RFQ.
For hazardous-area equipment, a more reliable approach is to trace the requirement from the cable specification through to the actual proposed cable entry arrangement.
This simple verification process can help identify discrepancies early and provides a clearer technical basis for RFQ evaluation, vendor clarification, and technical bid evaluation.
Join the conversation