Buying a Used Robot: Review the Control Box and Site Power Separately

A used robot that ran in the seller's facility may need an electrical review before it can be installed at the buyer's site. The control box, power supply arrangement and connected accessories must be identified separately. A seller's video or a plug that fits an outlet does not establish that the complete installation is suitable for the new location.

Identify what is included

Ask for the robot and control box manufacturer, complete model and the equipment included in the sale. Record whether the power cord, cabinet, teach pendant and external power supplies are included, and whether the system has been modified. Share equipment labels and wiring documents privately with the qualified people assessing the installation rather than posting sensitive identifiers publicly.

Some robot families offer different controller configurations. Universal Robots' control box interface overview describes standard and OEM controller options for its products. It is an example of why the actual controller version matters; it is not a specification for every used robot or a substitute for the relevant manual.

Separate mains supply from control signals

The electrical supply powering a controller is a different question from the low-voltage interfaces used to communicate with sensors or other devices. Ask the manufacturer or qualified electrician to identify the required supply, protective arrangements and the specifications for each interface. A reference to “24 volts” in an accessory description does not establish the requirements of the entire robot installation.

Universal Robots' UR7e user manual includes electrical information for that specific model and configuration. Its values must not be copied to a different robot. Use the document and revision applicable to the equipment being purchased, including the requirements for the buyer's jurisdiction and facility.

Ask about accessories and previous changes

A gripper, vision system or external controller may have its own power needs and may not be included in the robot's basic specification. Ask which devices were connected during the demonstration and whether their power supplies and documentation are part of the offer. A retrofit or replacement controller may change the information needed for the review, so request any available service records and drawings.

For a hypothetical purchase, a robot is sold with its arm and controller but without the external supply used for the seller's accessory. The buyer should identify that omission before agreeing on the complete setup. The example does not imply that any particular voltage or accessory is required; it illustrates why a parts list and installation assessment are useful.

Arrange a site-specific assessment

A qualified electrician and integrator should compare the actual equipment documentation with the receiving site's supply and safety arrangements. They can identify necessary work, protective devices, grounding and any restrictions under the applicable rules. Do not energize unfamiliar equipment, change a plug or connect wires based on a generic online article. The manufacturer's instructions and site procedures take precedence.

Discuss which checks can be performed before delivery and which require the equipment at the destination. A seller may provide a controlled demonstration, but that demonstration establishes only the tested configuration at the seller's site. It does not replace the receiving site's electrical and machinery safety assessment.

Before asking for a quote, describe the intended location and operating arrangement to the integrator. A robot installed in a fixed cell, a mobile cart or a different enclosure may require different consideration of cables, isolation and access. Environmental conditions and the way personnel reach the equipment can also affect the assessment. The buyer should not assume that the seller's cabinet or extension lead is suitable in a new setting merely because it was present during the demonstration.

Request an itemized estimate for any required site work and identify who will provide replacement cords, protective equipment or missing documentation. If the assessment cannot be completed before purchase, make the uncertainty visible in the transaction record and establish a process for resolving it. Neither a low purchase price nor a statement that the controller powered on proves the cost or safety of the final installation.

Put responsibilities and evidence in the handover

The transaction record should identify the included components, available manuals, known modifications and the person responsible for installation and commissioning. If a required document or component is missing, mark it as unresolved and agree how it will be obtained. A delivery receipt, electrical assessment and final operational acceptance are separate records.

Our guide to component-specific IP ratings and the used robot trading collection cover related equipment questions. A complete configuration record helps the buyer get an accurate assessment without treating the seller's operating conditions as proof for a new facility.