Pick a connector for internal PCB harnessing

Board-to-wire wiring inside an enclosure — power and signal from a PCB to other assemblies.

Use this when

• The connection is internal and protected by the enclosure.
• You want positive latches, polarization, and (in volume) secondary locks — not loose header pins.

Avoid this when

• The interface is external, sealed, or rugged — treat it as a sealed feedthrough or defense/rugged I/O unless the family is specifically sealed, latched, or potted.

Families to start with

• Molex Micro-Fit (and Mini-Fit / Nano-Fit) for internal power.
• PicoBlade / JST-GH and similar for signal.
• TE and Harwin families where their ratings and latches fit.

These are not "hobby" parts — professional versions have latches, polarization, secondary locks (TPA), and defined ratings. The dividing line is the specific family and rating, not the brand (see Major Connector Categories).

Search terms

• Micro-Fit wire-to-board latching connector crimp housing
• JST GH 1.25mm wire-to-board connector

Specs to check

• Current and wire gauge vs. the contact.
• Latch and TPA / secondary lock availability.
• Vibration exposure and whether the latch/lock is adequate.
• Tooling — the correct crimp tool and contacts for the exact family.
• Keying / polarization, especially in volume production.

Parts people forget

• Crimp tooling and the correct contacts for the family.
• The TPA / secondary lock and a keyed housing.

See What People Forget.

Common traps

• Pushing a hobby connector beyond its rating.
• Loose 0.1″ headers or bare solder joints where a latched, keyed housing belongs.
• No keying in volume production, so assemblies get cross-plugged.

Questions to ask a vendor/FAE

• What is the current/voltage rating of this exact family and contact?
• What crimp tool and contact part numbers are required?
• Is a TPA / secondary lock and a keyed/polarized housing available?

Example documentation bundle

• A selection table row for the harness.
• A source-controlled pinout with keying noted.
• A cable drawing and, for a controlled internal interface, an ICD entry.

Related: Decision Examples · Consumer / Hobby / Prototype connectors · for quick prototyping with pre-crimped leads and kit parts, the hobby track's Crimping and Marketplace Kits pages.