Electrical sub-assemblies built to drawing and bill of materials
The assembly of electrical sub-assemblies consists of placing on a single support the components and cabling that until now reached you loose, and leaving them positioned, fixed and connected according to your documentation. The same operation is often requested as electrical sub-assembly or electromechanical assembly, depending on which components go into the part number. The input is a drawing and a bill of materials. The output is an assembled sub-assembly, not a finished machine: your machine or final product remain yours. And the hard part is not assembling, it is agreeing where our scope ends and your process begins.
What it involves
What goes into electrical sub-assemblies and what does not
Assembly starts when the cabling is already finished. A custom-made harness is an item in itself; here that harness is positioned on the structure, routed where the drawing indicates, held at the planned points and connected to the elements already mounted. Alongside it go brackets, fasteners, actuators or modules, according to the bill of materials. When the part number is almost all cabling and connections we usually speak of electrical sub-assemblies, and when it incorporates support, fixing or moving elements, of electromechanical ones: the assembly work and the way of defining it are the same. What comes out is a sub-assembly assembled according to the agreed definition, with the scope closed in writing.
- Which components go into the sub-assembly and with which equivalents
- Position of each element on the support or structure
- Cable route and planned fixing points
- Connection, orientation of connectors and interfaces with your equipment
- Which operations stay outside and are still done by your line
Process control
Verifiable criteria of electrical sub-assembly assembly
The acceptance criterion for the assembly of electrical sub-assemblies is agreed in writing before the order and depends on the part number and the assigned manufacturer. On receipt the assembly is checked against your documentation; the electrical and functional verification of the assembly is defined separately and is not taken as included.
- Presence and part number of each mounted component
- Position and orientation against the drawing
- Cable route and fixings carried out at the planned points
- Connectors mated and accessible according to their interface
- What sampling is applied to the batch received
How this process is coordinated
How the assembly of electrical sub-assemblies is defined
Subcontracting the assembly of a sub-assembly is viable as soon as the operation is defined, and the physical assembly is carried out by the assigned manufacturer: Justicia Marin does not do it. The critical point is to agree where our scope ends and your process begins. Everything else follows from there.
We analyse the current assembly
We review what you assemble today piece by piece on your line and with what documentation you do it.
We fix the scope
We define in writing what the sub-assembly includes, which operations stay outside and in what state it is delivered.
Assembled sample
You receive the assembled sub-assembly to validate it on your real product before committing to a quantity.
Stable part number
The approved configuration is documented and repeated identically in later deliveries.
What has to be decided
What decides the scope of electrical sub-assemblies
Four decisions to close before assembling, both for an OEM that outsources an operation of its line and for an equipment manufacturer that wants to receive the assembly already integrated. None of them is about purchasing: all are about definition.
Which components go into the part number
A closed list, with the equivalents you accept in writing. What is not on the list does not go into the sub-assembly.
Where our scope ends
Which operations are done before reaching your line and which remain yours. It is the decision that is hardest to change afterwards.
How it is positioned, fixed and connected
Position on the support, cable route, fixing points and orientation of each connector, according to the drawing.
How the assembled sub-assembly is accepted
What is checked on receipt against your documentation. Electrical and functional verification is agreed separately.
Related information
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What this process actually covers
This process is carried out by manufacturers in our network selected for each project; Justicia Marin defines the requirement with you, coordinates the supply and verifies the batch received. We have no workshop, machinery or laboratory of our own, and we issue no certifications: certificates are those of the manufacturer or supplier that carries out the process. The specific means available and the level of control that can be achieved are confirmed in writing in the quote before the order. Integration does not include design of the assembly or functional validation of the final product: design and its validation are the customer’s responsibility, and our scope is to assemble and supply according to the agreed definition.
Where this capability ends: the manufacture of the cabling that is assembled here is custom wire harnesses, and it ends when the harness is complete. If what has to be assembled is a panel, that is control panel assembly, with its own scope. Electrical checks on the assembly belong to electrical verification and testing. As a technical reference of the sector, IPC/WHMA-A-620 devotes a section of its own to the securing and retention of cabling within the assembly.
Questions about the process
Electrical sub-assemblies: frequently asked questions
- What do you mean by electrical sub-assemblies?
- Bringing together cable, connectors and electrical parts — such as sensors, switches, relays, small motors or fans — on a bracket or in a module, positioned, fixed and connected according to drawing and bill of materials. The result is a sub-assembly that is ready to integrate into your machine or device. A selected manufacturer carries out the assembly.
- What is the difference from an electromechanical assembly?
- The terms overlap. We use electrical sub-assembly for the operation in which mainly cabling and electrical parts are brought together. In an electromechanical assembly the emphasis is on the complete sub-assembly, with more mechanical parts such as housings, brackets or moving parts. The way of defining it is the same.
- Why is defining the scope so important?
- Because unclarity about who does what is the most common cause of problems. We record in writing which parts fall within the sub-assembly, which operations remain outside the scope and in what condition it is delivered. That agreement is the hardest to change later, so we fix it before the first order.
- Is the assembly also electrically tested?
- Only if that is agreed separately. On receipt the assembly is checked against your documentation: presence, position, route and fixing. A continuity or functional test of the sub-assembly is fixed as a separate requirement, with criteria that can refer to IPC/WHMA-A-620.
- Who carries out the assembly of electrical sub-assemblies?
- A manufacturer that we select per project based on the components, the assembly operations and the volume. Justicia Marin fixes the scope with you, coordinates the sample and checks the batch and documentation received. We have no assembly department, workshop or machines of our own.
- Do you design the sub-assembly?
- No. The design of the assembly and the functional validation of your final product lie with you. We make sure the sub-assembly is assembled and delivered according to the agreed definition, and point out any unclarity in the drawing or bill of materials before production begins.
- Which data do you need?
- The drawing, the bill of materials with accepted alternatives, a photo of how you assemble it now, the operations you want to outsource, the checks wanted, the quantity and expected repeat orders. With that information we fix the scope and approach suitable manufacturers.
Do you assemble piece by piece today?
Tell us which operations your line carries out.
With the list of components, the drawing and a photo of the assembly we define the scope of the sub-assembly and its cost.
What you can send us
- Bill of materials or part numbers (Excel, PDF or text)
- Drawing or schematic for custom assemblies (PDF, DXF or similar)
- Estimated quantity and expected repeat orders
- Your priority: competitive price, certification or lead time
- Required standards or documentation
- Target delivery date
Tell us what you need to buy
We reply within 1 working day.