A DC contactor may be mounted in a proposed position only when the documentation for the exact offered configuration permits it. A photograph showing a similar device on its side is insufficient. Even an explicit permission to mount in any position does not remove the separate requirements for mounting hardware, cable support, terminal connections, clearances and application qualification.
The most useful RFQ starts with an installation drawing that shows the contactor, its base, gravity direction, terminal exits and surrounding structure. Match that drawing to a manufacturer instruction or a written application response before releasing the bracket and harness design.
This guide addresses purchasing and mechanical-integration evidence for DC contactors. It does not authorize high-energy switching tests, select protective devices or provide universal fastener torques. Qualified engineering personnel should approve the installation and any evaluation plan. Manufacturer examples explain document interpretation; they do not establish that a particular part or test service is available from SINAWATTS.
Separate orientation permission from electrical direction
Mounting orientation describes the physical position of the contactor relative to its specified reference, often including gravity. Main-contact polarity concerns the electrical direction through the power terminals under defined switching conditions. Coil polarity concerns the control connections. These are different fields and should appear separately in the review record.
A device described as position insensitive can still have direction-dependent electrical requirements. Rotating the housing does not grant permission to reverse terminal assignments. Similarly, a contactor with bidirectional electrical performance is not automatically approved for every mechanical installation position.
The main-contact polarity and interruption guide handles current direction. Use it alongside the installation review rather than collapsing both questions into a single checkbox labeled orientation.
For the mechanical question, request the full ordering code and the applicable drawing revision. A mounting style, auxiliary option or special configuration may have its own documentation. The buyer needs evidence for the part being offered, not a general statement about the manufacturer's entire contactor range.
Compare two genuine manufacturer statements within their scope
Albright's SW200 product page states that this contactor can be mounted horizontally or vertically, with the main contact studs pointing upward in the vertical arrangement. It says a downward requirement can be accommodated through a manufacturer adjustment. That wording is a reason to ask for a confirmed configuration, not permission for a buyer to modify the contactor internally.
Sensata's GX14BD product page identifies the GX14 family as not position sensitive and permits mounting in any position. That is a different documented orientation statement. It does not establish that GX14 is an electrical or mechanical substitute for SW200, and no such substitution is recommended here.
The purchasing lesson is specific: retain the qualifier attached to the offered model. A comparison sheet that reduces both statements to horizontal or vertical mounting loses the SW200 restriction. A sheet that assumes every DC contactor needs the same restriction would also misrepresent the manufacturer evidence.
On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.
| Documentation statement | What the buyer can conclude | What still needs review |
|---|---|---|
| Named model permits specified positions | Those positions are documented within the stated scope | Exact variant, hardware and surrounding installation |
| Named model requires a particular terminal direction | The direction is part of the configuration requirement | How the equipment drawing maintains that direction |
| Manufacturer offers an adjusted configuration | An alternative may be possible after confirmation | Ordering identity, applicable documents and approval |
| Named model permits any position | Position itself is not restricted by that statement | Electrical direction, support, clearances and other ratings |
| No orientation statement is supplied | The evidence is incomplete | Written clarification before layout release |
Draw the position so two people interpret it the same way
Avoid a requirement that says only horizontal mounting. It can refer to the mounting plate, the contactor axis, the power-terminal face or the complete equipment. Different interpretations can produce incompatible quotations while each supplier believes it complied.
Provide an annotated view with an upward arrow representing gravity in the normal installed state. Mark the mounting face, the manufacturer's reference features and the power-terminal labels. Include enough surrounding structure to show whether the device is on a floor plate, wall plate or overhead bracket.
If the equipment operates at more than one attitude, identify the relevant range and operating states for engineering review. A stationary enclosure installed in one position differs from equipment that changes attitude in use. Do not invent an allowable tilt angle when the manufacturer has not supplied one.
Distinguish normal operation from transport and storage. A contactor may experience a shipping orientation that is different from its powered service position. Ask for applicable handling information, but do not assume permission for one state automatically covers the other.
Use a drawing revision as the contractual reference. A sentence in an email can explain the requirement, but the released drawing should preserve the geometry that manufacturing and service personnel will actually follow.
Resolve model identity before accepting an exception
A manufacturer response should identify the complete offered part and the installation question it answers. If the response depends on a special adjustment, bracket or suffix, include that identity in the purchasing record. Otherwise, a later order may arrive under a familiar family name but without the required configuration.
Ask whether the proposed exception changes any other relevant published behavior. Do not assume it does, and do not assume it cannot. Request the applicable documentation and let engineering determine which existing qualification decisions remain valid.
Separate preliminary application advice from a released configuration statement. A message saying that an arrangement may be possible is useful during design exploration; it is not the same as confirmation that the quoted ordering code incorporates the necessary change.
For replacements, record the original and proposed configurations side by side. An alternative that fits the same holes may still have a different terminal direction, mounting instruction or accessory arrangement. The comparison should state which attributes match and which require fresh evidence.
Retain rejected alternatives with a factual reason. “Orientation not documented for the proposed installation” is more precise than calling a device unsuitable in every application. It also tells a future reviewer which information would allow reconsideration.
Treat the base attachment and power connection as different joints
The mounting fasteners secure the contactor to its support. Power-terminal hardware secures the electrical connection. They can have different sizes, materials, torque requirements and assembly instructions. A single torque value written beside the contactor image is therefore an ambiguous purchasing requirement.
TE's EV200A catalog section, page 7-22 illustrates this separation: its outline drawing identifies power-terminal hardware separately from mounting hardware and gives distinct tightening ranges. Those instructions belong to the documented configuration. They should not be transferred to another contactor merely because a thread diameter appears similar.
Create separate assembly rows for the base attachment, each power connection and any accessory attachment. Refer to the controlling document rather than copying isolated numbers without their conditions. Where hardware is not supplied, identify the responsible party and the agreed specification before pricing is finalized.
Request the permitted mounting-surface and fastener details from the applicable instructions. If a custom bracket introduces a different thickness, a threaded engagement question or an inaccessible fastener, resolve that issue with the appropriate designer. Do not compensate for a poor fit by increasing torque.
For related conductor-interface questions, the battery-busbar terminal-stack guide explains why joint identity and stack arrangement need their own records. A contactor installation should preserve that distinction even when all components share one mounting plate.
Show how the cables and busbars are supported
An orientation drawing should include the actual conductor exits and the first supports. Show whether the connection uses flexible cable, a formed busbar or an assembly combining both. Record the lug geometry and the intended route so the offered installation can be reviewed as a whole.
Do not treat a power terminal as an unspecified structural support. Ask engineering and the manufacturer for the relevant terminal loading limitations or approved connection arrangement. Where no allowable mechanical load is published, mark the question unresolved instead of inventing a force limit from the stud diameter.
A cable route that fits before tightening can still be poorly aligned. Ask for a fit assessment using the intended conductor length and supports, with the installation safely de-energized. The purpose is to check geometry and assembly access, not to bend a conductor into position by pulling against the contactor terminal.
Separate the contactor's permitted position from the conductor's routing requirements. A position-insensitive device may make a layout possible, but the resulting cable bend, support location or busbar alignment still needs its own approval. Rotation is a layout option, not a universal solution to an interface mismatch.
Include service movement where it exists. If an assembly is removed for maintenance, identify what must be disconnected and which supports are disturbed. A service instruction that leaves a heavy cable hanging from a terminal may create a condition absent from the original installation review.
Review the bracket as part of the installed configuration
A bracket drawing should identify its revision, material specification, thickness, attachment points and the contactor mounting pattern. The responsible designer should establish its structural suitability. Purchasing should verify that the quoted bracket matches the released drawing and that any deviation is visible before manufacture.
Do not infer vibration suitability solely from a contactor's component rating. The installed bracket, surrounding panel and conductor supports define the application arrangement. Request evidence or an engineering assessment that explains the relationship between the component test setup and the proposed installation.
If isolators or flexible mounts are proposed, treat them as an identified design change. They are not automatically beneficial and should not be added as an undocumented workshop adjustment. Their effect and applicability belong in the engineering review.
Record the connector and cable access envelope as well as the mounting-hole pattern. A bracket can satisfy the hole positions while obstructing a latch, cover, inspection point or tool path. Ask for an assembly review that covers the complete installation sequence rather than only the finished external dimensions.
When a supplier proposes a standard bracket, request its exact identity and an installation drawing. A catalog illustration can communicate the concept, but the order needs enough detail to prevent an apparently similar bracket from being substituted later.
Keep thermal, insulation and service clearances separate
A permitted mounting position does not establish the temperature inside a finished enclosure. Identify the relevant surrounding components, conductor arrangement and enclosure conditions for the engineering thermal review. Do not infer current capability from open-air catalog data without checking its stated conditions.
Likewise, position permission does not set electrical clearances between exposed conductors, grounded structure and covers. Those requirements depend on the applicable system design and standards. Record the approved spacing references and verify that the installed lug and hardware stack remains within them.
Distinguish electrical spacing from physical assembly space. A design can satisfy a specified electrical clearance yet leave inadequate access for the required tool, cover removal or mating connector. These are separate review rows because the corrective action may be different.
Sensata's GXC Smart-Tactor datasheet combines an orientation-invariant statement with separate mounting, connection and environmental information. Its structure is a useful reminder that orientation permission is one attribute within a larger installation specification. The document is specific to its identified GXC configurations.
Use the OEM and ODM enquiry page to describe an assembly requirement with its drawings and open interfaces. Confirm the actual scope of any proposed support, part supply or evaluation in the response; a category page does not establish those capabilities.
Send the contactor ordering code, installation view and unresolved mounting questions so the RFQ can address the proposed arrangement instead of an assumed catalog position.
Compare a hypothetical enclosure redesign before ordering parts
Consider an explicitly hypothetical enclosure redesign. The original layout uses a contactor in a documented position. A revised enclosure moves the mounting plate to a sidewall and changes the cable exit route. The buyer receives three proposals. These are invented purchasing scenarios, not test results, customer cases or recommended contactor substitutions.
Offer A retains the original model and says the new position is acceptable because the mounting holes still align. Offer B proposes a position-insensitive model but has not resolved the power-terminal and control interfaces. Offer C retains the original family through a manufacturer-confirmed configuration and supplies a revised installation package, while an external cable-support detail is still open.
On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.
| Hypothetical proposal | Useful evidence supplied | Required next decision |
|---|---|---|
| A: same holes, no orientation confirmation | Basic dimensional fit | Obtain applicable permission for the actual position |
| B: position-insensitive alternative | Documented orientation flexibility | Review electrical, control, connection and support compatibility |
| C: confirmed configuration, incomplete cable support | Traceable position approval and installation drawing | Close the support detail before assembly release |
The least expensive component is not necessarily the least expensive completed arrangement. A proposal may require bracket changes, conductor changes, further engineering review or different service documentation. Compare those items explicitly without inventing a cost saving or assuming every change requires a complete retest.
The decision should identify the smallest remaining evidence gap. Offer A may be resolved by an applicable manufacturer statement, or it may require a different configuration. Offer B needs a broader interface review because position permission alone does not prove interchangeability. Offer C needs the named support decision closed; its other completed evidence should not be discarded unnecessarily.
Keep the original layout approval until the replacement package is released. This avoids a purchasing change being interpreted as permission to build an intermediate arrangement that no reviewer has approved.
Request a professional evaluation with a clear boundary
If existing documentation cannot resolve the installation, ask engineering to define the question for a competent supplier or laboratory. The plan should identify the contactor, mounting arrangement, conductor supports, operating states and acceptance references. The provider should explain what the proposed evaluation can and cannot establish.
Separate a mechanical fit review from functional or environmental qualification. A de-energized fit assessment can document access and geometry. It cannot establish switching endurance, fault interruption or behavior under a defined vibration exposure. A successful switching demonstration likewise does not automatically cover a different environment or service history.
Retain specimen and drawing identities in the final report. If the test uses a substitute bracket or simplified conductor arrangement, record that explicitly and obtain an applicability decision. A favorable result for an unidentified setup is difficult to use when a later production change is questioned.
Do not create an improvised energized test at the purchasing desk to settle uncertainty. The appropriate response to missing evidence is a defined engineering and supplier review, with any necessary evaluation performed under an approved plan and suitable facilities.
Make quotation scope and production checks consistent
Ask the quotation to identify the contactor ordering code, bracket, mounting hardware and connection accessories separately. State which items the buyer supplies and which arrive assembled. This prevents a price comparison from confusing a bare component with a documented installation kit.
Require exceptions to the drawing to be listed in the supplier response. An unqualified statement of compliance is less useful than a precise list of matched references and open conditions. If a special configuration is proposed, ask how it will be identified at receiving and on replacement orders.
The production control plan should verify the approved configuration without overstating what routine inspection proves. Appropriate checks may include part identity, orientation against the drawing, specified hardware, conductor support and documented assembly records. Engineering and quality should define the actual checks and their acceptance criteria.
Preserve traceability when a device is replaced in service. The replacement record should identify the applicable configuration and any installation change. A familiar appearance or similar current rating should not bypass the release process for a mechanically different substitute.
Keep an installation decision register
Create a short register linking each open question to its owner, evidence and disposition. Typical entries include orientation permission, special configuration identity, base attachment, terminal connection, cable support, bracket suitability and access. This makes it clear which part of the installation is approved and which remains unresolved.
Attach the manufacturer's response to the drawing revision it reviewed. If the drawing later changes, the owner can assess whether that response still applies. Without the revision link, a valid answer to an earlier arrangement may be reused accidentally for a different one.
Record assumptions as assumptions. For example, a design review may rely on a cable support supplied by the equipment integrator. The purchasing release should name that dependency and ensure it appears in the final assembly documentation. Leaving it only in meeting notes makes the approval difficult to reproduce.
Close the register with the released installation identity and the conditions that trigger reassessment. This preserves the value of completed work while preventing orientation permission from expanding into an unsupported claim about the whole equipment.
FAQ
Can every sealed DC contactor be installed upside down?
No general rule follows from a sealed construction. Use the exact model's current documentation or a specific manufacturer response. If the intended position is not covered, keep it open for review. Neither the housing appearance nor an ingress-protection statement establishes permission for a different installation attitude.
Does permission for any position mean the main terminals can be reversed?
No. Physical position and electrical direction are separate attributes. Keep the manufacturer's terminal markings and the approved current-direction assessment in the electrical design. A position-insensitive contactor can still have application-specific switching requirements that must be reviewed independently of the mounting drawing.
What does a supplier mean by horizontal mounting?
The phrase is incomplete unless its reference is clear. Ask for an annotated drawing showing the mounting face, contactor reference features, terminal labels and gravity direction. Use that drawing in the order so the supplier, enclosure designer and assembly team interpret the requirement consistently.
Can we reuse the old bracket for a replacement contactor?
Only after the proposed replacement and installation have been reviewed. Matching holes establish one dimensional attribute, not complete compatibility. Check the applicable position permission, attachment instructions, conductor interfaces, clearances, access and support arrangement. Preserve the approved replacement identity so later service orders do not reopen the same ambiguity.
Should mounting bolts use the power-terminal torque?
No such assumption is justified. They are different joints and may have different hardware and instructions. Use the applicable manufacturer documents for each connection and the released assembly process. If a document gives only one joint's requirements, obtain the missing information rather than copying the available number.
Does a component vibration rating cover our custom bracket?
It does not automatically establish the performance of the complete installation. Request the tested mounting conditions and compare them with the proposed bracket, panel and conductor supports. Engineering should decide whether existing evidence is applicable or whether additional analysis or evaluation is needed for the changed arrangement.
What should be included to obtain a meaningful price and delivery response?
Send the exact contactor identity, installation drawing, quantities, required accessories, existing approvals and unresolved questions. Ask the supplier to state what is included and which conditions remain to be confirmed. Availability, prices, minimum quantities and schedules depend on the actual request and should not be inferred from general catalog information.
Send a mounting-orientation RFQ with a controlled drawing
Provide the complete ordering code, manufacturer document references, gravity-marked installation view, bracket drawing and conductor-support arrangement. Include separate rows for electrical direction, mounting hardware and power connections. Mark the required approval owner for each open issue so an answer can be turned into a controlled release.
Send your DC contactor mounting-orientation and installation RFQ package. The objective is a documented arrangement that can be purchased, assembled and replaced consistently, with clear evidence boundaries and no reliance on an assumed universal mounting rule.