Molex SL vs C-Grid III: Checking the Exact Mating System
Table of Contents
“Molex 2.54 mm” leaves several interfaces unresolved. SL and C-Grid III include multiple housings, headers and termination options; the family name does not identify a complete mating system. A useful comparison follows the manufacturer's part relationships and then closes the gaps at the exact configuration level.
Start with the installed board part when it is fixed. For a new design, review candidate systems against the same project requirements. The examples below illustrate two independent documentation trails, not interchangeable components or an equal-circuit size comparison.
Read Mates With and Use With as different relationships
A housing's mating table points toward the component on the other side of the connection. Its use-with table may identify contacts or other components installed within that housing. Confusing the two can leave a purchasing list with two receptacle components and no defined board interface.
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| Documentation step | SL example | C-Grid III example |
|---|---|---|
| Exact cable housing | 50579404; four circuits, single row, Version G positive latch | 901420008; eight circuits, dual row |
| Pitch | 2.54 mm | 2.54 mm |
| A listed mating header family | 70543 | 90130 |
| Listed female contact family | 70058 or 71851 | 90119 |
| Exact header example for further review | 705430003; four circuits, vertical, shrouded | 901301108; eight circuits, vertical, shrouded |
Sources: SL housing 50579404, C-Grid III housing 901420008, SL header 705430003 and the 90130 series chart.
The housing pages list mating families, not a complete project-specific bill of materials. Matching a header's family and circuit count narrows the review; it does not remove the need to check the configured drawings, contact finish and application requirements. The table deliberately leaves the exact crimp contact open until the wire and termination details are known.
Preserve the configuration when moving to a drawing
A series can contain different circuit counts, orientations, tail lengths and finishes. A procurement record that retains only “70543” or “90130” loses the configuration required to reproduce the interface.
For the cited SL header, Molex lists a 3.30 mm PCB tail and a gold mating finish. The selected C-Grid III header entry lists a 2.90 mm tail and tin plating. These details belong to those exact examples. They are not general differences between all SL and all C-Grid III parts.
The PCB designer should confirm the recommended footprint, board thickness and mounting process for the selected header. The cable review should confirm the mating housing and contact system. Neither team can finish its part by using the nominal 2.54 mm pitch as the entire specification.
Where a manufacturer lists a permitted relationship across product families, record that exact relationship and its conditions. Do not extend it to every member of either family, another plating option without review, or an unbranded part described as compatible.
Check retention as a complete installed arrangement
The SL example's Version G positive latch is a specific housing feature. C-Grid III documentation includes several constructions and describes friction-lock options. A family comparison should not turn that variety into a blanket statement that all members lock in the same way.
Review the selected mating drawings to locate the engagement features and the permitted insertion and removal direction. Add enclosure access, nearby components and the cable support arrangement. A housing that can mate on a bench may be difficult to release once installed.
Retention of the mated housings is also separate from retention of a crimp contact within its housing. If a terminal backs out, replacing the header family may not address the cause. The terminal-backout guide covers that separate investigation.
Choose the terminal after defining the wire
Use the exact housing's documented contact families as the starting point, then select the contact for conductor size, insulation dimensions, finish and manufacturing process. Ask the supplier to identify the applicable termination tooling and instructions for that exact contact.
Do not transfer a contact from one system to another because it appears to fit a cavity. Contact retention geometry, mating engagement and the crimp arrangement all need a documented basis. Similarly, a terminal's wire-range listing does not define the current capability of the finished harness in every environment.
For an alternative component proposal, obtain the alternative manufacturer's own drawings and verification evidence. Original Molex documentation describes original parts; it does not automatically qualify a replacement proposed against the same reference number.
A fictional receiving-review problem
EX-MATING-58 is an invented purchasing case. A requisition says “four-way Molex 2.54 mm cable for the existing board.” The buyer has a photograph but no board BOM. A supplier proposes a C-Grid III assembly while the service team believes the installed connector is SL.
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| Evidence | What it establishes | What it does not establish |
|---|---|---|
| Photograph and measured pitch | Candidate search information | Exact manufacturer, variant or permitted mate |
| Existing board BOM recovered from engineering | Board-part identity for review | Correct cable contact and wiring by itself |
| Housing mating-family listing | A documented relationship to investigate | Every exact configuration or substitute |
| Supplier's proposed complete BOM and drawings | A reviewable assembly definition | Approval before the technical checks are closed |
| Approved sample and agreed verification record | Evidence for the documented sample scope | Permission to change later components silently |
The team first resolves the existing board part. It then checks the proposed cable against that interface, rather than accepting a family change as a purchasing equivalent. If the board itself is to change, that becomes a coordinated engineering revision with its own sample and verification scope.
Complete the record before placing the cable order
Capture the full board-header reference, housing and contact references, wire specification, populated cavities and defined pin view. Add cable length, routing constraints, required identification and verification. Attach the source drawing revisions used in the review so later substitutions can be recognized.
Keep unresolved points visible in the quotation. For example, a supplier can price a proposed assembly while the customer still needs to confirm the installed header; that pending item should not disappear when the order is raised. The connector documentation guide explains the roles of drawings and application specifications in closing such questions.
SL and C-Grid III questions
Does equal pitch prove SL and C-Grid III compatibility?
No. Pitch identifies contact spacing. Compatibility needs the documented mating relationship and the selected mechanical and contact configurations.
Is a family listed under Mates With enough to release an order?
It is a useful starting point. Confirm the full mate, circuit count, orientation, finish, drawings and cable requirements before release.
Can a compatible alternative inherit Molex ratings?
No. Evaluate it using its own manufacturer's evidence and the project's requirements. Keep original and alternative components explicitly identified.
Request a review against the actual equipment interface
For custom Molex cable assemblies, provide the equipment-side part number, proposed cable BOM, wire and pin map. Contact Zeakka to coordinate sourcing and supplier clarification. Original parts within a finished assembly remain subject to exact-part review and availability; this guide does not offer loose original components or approve a substitute.
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