How to Get Installation Drawings from Suppliers for Multi Cable Transit Approval?

Every week our engineering desk hears the same problem: a buyer needs installation drawings for multi cable transit approval, the review is Friday, and the incumbent supplier sent a brochure.

To get installation drawings for multi cable transit approval, send the supplier a complete data package—cable schedule with outer diameters, transit frame dimensions, deck or bulkhead construction, fire class, and IP rating—then request project-specific drawings, DXF/STEP files, and matching Type Approval Certificates and test reports for formal submittal.

A brochure will not pass a class society ¹ or a client engineer IATF 16949 ². A drawing that shows your exact penetration will. The gap between those two documents costs weeks when it is discovered late. Below I explain what to ask for, how to check it against your existing frames, which file formats your engineers need, and how to prove the drawing matches the certificates.

What Installation Drawings Should I Request Before Approving a Multi Cable Transit Supplier?

Last year our QC team rejected a drawing set before it left the factory. The frame view was right, but the filler layout did not match the buyer's cable list.

Request a project-specific penetration seal drawing set: frame general arrangement with transit frame dimensions, packing plan showing each cable position and module size, compression unit assembly and stayplate configuration, mounting detail with weld or bolt specification, integrated bill of materials, and a certificate reference block.

That rejected drawing taught us something simple. A drawing is only useful if a reviewer can trace every line back to a real cable, a real wall, and a real certificate. So when I talk about installation drawings for multi cable transit approval, I mean a set of sheets, not one picture.

Catalog drawing or project-specific drawing?

Some project teams push back here. They say the standard catalog sheet is good enough and saves time. I understand the instinct. A catalog sheet is fine for budgeting and for early layout. But an approval reviewer is not pricing the job. They are asking whether this penetration, with these cables, in this deck, will hold fire and water. A catalog sheet cannot answer that. It shows a frame. It does not show your cables. In my experience that is the single most common reason a cable transit seal submittal bounces back.

My recommendation is a two-stage approach. Use the catalog drawing at RFQ stage. Then, before purchase order, insist on the project-specific set below.

The sheets a complete drawing package should contain

What we need from you before we can draw

Our engineers cannot produce the packing plan without a cable schedule. We ask for cable ID, outer diameter, insulation type, quantity, routing side, and required spare capacity. We also need the penetration location, the construction type (steel bulkhead, concrete wall, container roof, switchgear floor), the fire class, and whether the area is hazardous. Because our TSC square modules use step-core, halogen-free EPDM, one module size covers a range of diameters. That usually consolidates the module count, but only if we know the real diameters first. A drawing based on guessed diameters is a drawing that will be redrawn.

How Can I Verify Drawing Compatibility With My Existing 120-Frame Cutouts?

A sourcing manager at a BESS container builder in Germany once sent us a photo of an installed frame and asked one question: will your modules fit this cutout?

Verify compatibility by overlaying the supplier's frame drawing on your as-built cutout: check internal opening width and height, frame depth, flange thickness, bolt hole pattern, and module stack height. Then confirm the model cross-reference table and test a free validation sample in a spare frame before approval.

That photo was a good start, but a photo is not a drawing. We asked for the as-built frame drawing and a tape measurement of the internal opening. Then we sent our TSC module drawing back with dimensions marked at the same points. That is the basic method. You are checking two drawings against each other and against the steel that already exists.

A step-by-step compatibility check

1. Get the as-built frame drawing, not the design drawing. Frames get welded slightly out of square. Measure the real opening.
2. Match the frame family. The common 120 frame family is named for its nominal depth. Our modules and frames are dimensionally compatible with this family, so they drop into existing cutouts as a qualified second source.
3. Compare module stack height. The total height of modules plus stayplates plus compression unit must equal the internal opening with the correct compression travel left over. Too little travel and the seal will not reach pressure. Too much and the compression unit bottoms out.
4. Check the module footprint. Width and depth of each module must sit flush with the frame walls and the stayplate configuration.
5. Confirm the cross-reference. Our model cross-reference table maps the existing supplier model to the equivalent DEWIN model. Use it to rebuild the packing plan module by module.
6. Test a validation sample. We ship free validation samples. Fit them in a spare frame or a test frame on your bench before you approve the drawing.

The dimensions that decide fit

Why cable schedule integration matters here

Fit is not only about steel. It is about cables. If your cable schedule changed since the original frame was packed, the old packing plan is wrong too. So I ask buyers to send the current schedule with the frame drawing. Our packing plan software then rebuilds the layout using the step-core range of each module. That gives you a new penetration seal drawing that fits both the existing frame and the current cables.

Which CAD or STEP File Formats Do I Need for My Engineering Team's Approval Process?

There is a trade-off we weigh on every drawing request: a native 3D model gives the buyer's engineers more, but a locked PDF is what the approval authority stamps.

Request three layers: a 2D DXF or DWG penetration seal drawing for the submittal package, a neutral STEP 3D model for clash detection in your master model, and an Excel or CSV bill of materials tied to the cable schedule. Add a signed PDF for the formal approval record.

Both sides of that trade-off are right. So we supply both. The engineering team gets the editable and model-ready files. The approval file gets the frozen, signed sheet. The mistake is to supply only one and expect it to do both jobs.

The file formats and who uses them

BIM and CAD blocks for clash detection

More project teams now expect model-ready outputs, not scanned PDFs. Modular data center builders and BESS container integrators run clash detection before steel is cut. A STEP model of the frame and modules lets them check that the transit clears busbars, cooling ducts, and door swings. Our engineers export STEP and DXF for the TSC and TSR series and for our transit frames. We provide these files with English technical support, so questions about geometry get answered by the person who modeled the part.

Cable schedule integration in the BOM

The Excel output matters more than people think. When the BOM carries the same cable ID column as your schedule, procurement can audit module quantities against real cables. Spare capacity becomes a visible line, not a guess. This is also the file that lets a digital twin stay current when cables are added later during the asset's life.

Newer requests we hear

Buyers sometimes ask for QR codes on the drawing that link inspectors to the material certificate for that unit. Others ask for 4D installation sequences for dense transits, or thermal-load-optimized packing layouts. These are reasonable asks for large offshore or data center projects. I would rank them behind the three core layers above. Get the DXF, STEP, and BOM right first. The rest builds on them.

How Do I Confirm Installation Drawings Match Certified Fire and IP68 Test Reports?

One lesson took us a few projects to learn: a valid Type Approval Certificate on file does not mean the drawing in the submittal is covered by it.

Confirm the match by tracing each drawing element to the certificate scope: frame type and size, module material and range, compression unit and stayplate arrangement, insulation on the fire-exposed side, and A-0 or A-60 class. Then check IP68 and pressure test reports name the same configuration.

The lesson came from a drawing that was technically correct but referenced the wrong page of a certificate. The reviewer caught it. We fixed it in a day, but the buyer lost a review cycle. Now our drawings carry a certificate reference block that names the exact configuration.

Product approval is not installation approval

This is the distinction most buyers miss. Product approval says the cable transit seal family passed fire, water, and gas tests in a defined configuration. Installation approval says your specific penetration is built inside that configuration. Suppliers sometimes argue that a certified standard detail is sufficient. Engineers and class surveyors answer that they need evidence the exact installation matches the certified scope. The surveyor is right, and the answer is not to fight it. The answer is to make the trace explicit on the drawing.

Our factory runs ISO 9001 ³ and IATF 16949 systems and is BV-approved. Our modules are tested for A-0 and A-60 fire rating ⁴, IP68 ingress protection ⁵, and watertight and gas-tight sealing from 0.01 to 0.4 MPa. We provide those test documents on request. But the certificate is only half the evidence. The drawing has to point at it.

Tracing the drawing to the evidence

Who signs off, and when

The review chain is longer than the supplier. Your internal engineering reviews first. The client engineer reviews next. For marine and offshore work, the class society or certifying authority reviews the firestop submittal and the penetration drawing before installation. Installation then runs under QA/QC supervision, and the final inspection produces as-built records, redline markups, and photos. The drawing must survive every step. That is why I tell buyers to send the target approval body with the data package. A drawing prepared for a class surveyor is formatted differently from one prepared for a building inspector.

The rejection list I keep on my desk

• Missing cable outer diameters or cable IDs
• Module range that does not match the Type Approval Certificate
• Incorrect fire class for the division
• Unclear weld or bolt detail
• Drawing does not match the as-installed steel
• Certificate reference points to a different configuration

Every item on that list is avoidable if the supplier receives complete inputs and returns a traceable drawing.

Conclusion

Waiting on a brochure will not pass an approval review. Send a complete data package, demand project-specific drawings with traceable certificates, and validate fit with a free sample.

Footnotes

1. IACS is the authoritative body representing classification societies that approve marine cable transits. ↩︎

2. Official IATF site for the automotive quality standard used by the manufacturer. ↩︎

3. Official ISO page for the quality management standard cited in the article’s manufacturing section. ↩︎

4. IMO’s official fire protection page covering the A-60 standards required for offshore cable transits. ↩︎

5. Official IEC explanation of IP ratings, specifically the IP68 standard mentioned for sealing performance. ↩︎

6. UL provides authoritative certification and inspection standards for firestop submittals and penetration seals. ↩︎