How to Select Power Shelf Internal Wire

A Power Shelf contains circuits with different electrical and mechanical duties. Begin with the approved schematic and interface drawings, then select each wire construction. A single preferred UL style should not be applied across the entire shelf without review.

1. Map the circuits before choosing a wire

Circuit	Information to collect	Selection focus
AC input and internal distribution	Operating voltage, phase arrangement, branch protection, routing and equipment requirements	Insulation rating, thermal margin, clearances, terminal compatibility and mechanical protection
DC output connections	Output voltage range, continuous and peak current, parallel paths and connection geometry	Conductor resistance, voltage drop, temperature rise, current sharing and termination performance
Auxiliary power and controls	Supply voltage, load current, signals, connector pitch and harness routing	Appropriate gauge, insulation dimensions, identification and separation from power circuits
Protective bonding	Bonding function, protective-device coordination, mounting and applicable equipment requirements	Approved conductor sizing, identification and reliable bonding connections

OCP rack designs may distribute shelf DC output through a busbar. Do not infer a round-wire requirement from the presence of a Power Shelf: confirm which connections are wired, busbar-connected or integrated into the module. The relevant rack specification and OEM design control the interface.

2. Calculate for the actual operating conditions

For a DC connection, start with current, total circuit resistance and allowable voltage drop. Include both outgoing and return paths and the terminal/contact contribution. Resistive heating follows I²R, so connector resistance and conductor resistance both matter. Select a preliminary construction, then validate the complete assembly under the required load and cooling conditions.

Use the worst relevant ambient temperature, bundle arrangement, airflow, duty cycle and permitted conductor temperature. Do not infer an allowable current solely from AWG or insulation temperature rating. Parallel conductors also require a review of path resistance, connection symmetry, protection and current sharing.

3. Screen wire families without assuming interchangeability

PVC candidates: UL1015, UL1028, UL1283, UL1284 and UL10070 may be evaluated where the exact construction meets the circuit and temperature requirements.
Crosslinked candidates: UL3271, UL3289 and UL3386 warrant review when their specific ratings, dimensions and processing characteristics fit the design.
Silicone candidates: UL3133 and UL3135 can be considered for heat-exposed or routing-sensitive internal connections, subject to the approved construction and protection against installation damage.
Other voltage candidates: review UL10269, UL10974 and UL11627 against explicit AC/DC requirements. A 2000VAC designation does not establish 2000VDC suitability, and a 600VAC wire must not be proposed for an 800VDC circuit without suitable explicit coverage.

This list is a starting point for engineering review, not a declaration of GFINE approval scope, stock or compatibility with an OCP product. Check the supplier file and datasheet for the quoted conductor range, temperature, voltage, flame rating and use conditions.

4. Match the wire to the connector and production process

Confirm terminal conductor range, permitted strand construction, insulation diameter, strip length and tooling. Evaluate cutting, stripping and crimping with production samples. Inspect crimps and check retention and electrical performance using the customer-approved criteria. Ensure the final routing respects bend space, strain relief, sharp-edge protection and service access.

5. Treat busbars and flexible links as designed interfaces

A flexible busbar or braided copper link may suit a defined connection, but changing from a cable requires review of mounting, contact area, insulation, clearance, movement and mechanical support. It does not automatically replace a UL3133 AWG4 wire. Likewise, an Active Electrical Cable (AEC) used for high-speed data is a signal interconnect, not the shelf power conductor.

6. Send a complete RFQ and validation package

Circuit function, maximum operating voltage and AC/DC designation.
Continuous/peak current, duty cycle, ambient temperature and cooling conditions.
Conductor size, copper finish, stranding, finished diameter and routing length.
Connector/terminal drawing, approved tooling and assembly requirements.
Applicable equipment standard, required wire approval and flame-test designation.
Colour, marking, reel length, sample quantity and expected production demand.

GFINE can review wire parameters against the enquiry and prepare a construction proposal for sample evaluation. The equipment manufacturer must approve suitability before production release.